Tag: vertical agriculture

Over the course of the next few years, these data and observations will be cumulatively compiled across sites to determine if each plant has wide adaptability and appeal. Here especially, the Master Gardeners’ experience will be invaluable. They will be able to render an opinion on a plant’s garden-worthiness, as well as the response of the public to it over the course of its life in their garden. A plant thought interesting to an enthusiast may be completely unappealing to the average gardener, and might well prove unmarketable except at plant sales. That is not the plant we are looking for. On the other hand, if a plant performs well and has wide appeal, we can create demand from an educated gardening public for these environmentally friendly introductions before they are even in the retail outlets. In addition, the wide range of demonstration garden situations will give us a more comprehensive set of cultural recommendations for growers, landscapers and home gardeners. Some of the Master Gardener groups have already begun sharing information on the program and its plants through garden signage, newsletters and local radio programs. In most regions of the country, propagation and production development is the purview of the commercial wholesale nursery industry. In Georgia, growers are invited to the university managed test gardens each year to take cuttings of plants they are interested in and are encouraged to use their expertise to propagate and produce them . In Arkansas, the nursery industry actually provides the university with the initial plants for their introduction trials, and the university provides them with the results . In our case, we are trying to persuade both the commercial industry and the public to use environmentally responsible,square plastic pot low-input plants with which they may be unfamiliar. Because of this, some of the initial propagation hurdles may have to be cleared by university and extension research.

The highly successful Texas Coordinated Educational and Marketing Assistance Program is a good model for cooperation between the university and the ornamental horticulture industry . If a plant passes the various climate zone trials but is difficult to propagate, university and extension researchers tackle the problem until the best method is discovered. Graduate researchers at UC Davis and arboretum staff are continuing propagation research on our plants. Additionally, a commercial master propagator is currently working on protocols for several species, contributing the expertise of one who understands the requirements of mass production.Once a plant is ready for marketing, production schedules will be worked out to ensure sufficient supply to meet the expected demand at introduction. The National Arboretum has a regional cooperative program whereby growers and universities in seven southeastern plant-hardiness zones evaluate and increase the stock of plants slated for introduction . To ensure that these new plants are carefully screened, the National Arboretum controls their release through Material Transfer Agreements and centralized data analysis. After that, all the parties with an interest are involved in all aspects of testing and production, especially stock increase. In this way they can be assured of supply to meet the demand once a release date is announced . In the hope of implementing at least part of the National Arboretum’s model, the California Center for Urban Horticulture and its director Dave Fujino are currently acting as coordinators for the program’s coalition, which comprises the UC Davis Arboretum, UCCE researchers, the previously mentioned commercial master propagator, several wholesale growers, a distributor and a horticultural marketing expert, all of whom have generously donated their time and resources. With the help of all parties, the first set of UC Davis Arboretum All-Stars is expected to be released in fall 2009.In the future, we hope to broaden the coalition of cooperating entities to include other botanical gardens, California Native Plant Society members, other university and junior college faculty with expertise in this area, and more members of the nursery and landscape industry with an interest in growing, selling and planting low-input plants. This model is based on several successful program examples such as those in Texas and Oklahoma, where candidates for field trials are put forth at annual meetings of large advisory committees composed of members from academia, extension services, botanical gardens and arboreta, professional landscape and nursery associations, and individual industry representatives.

In these states, this group analyzes the results of the trials as well, and decides which plants are actually worthy of introduction . Their goal, like ours, is to identify and promote plants that do well with minimal inputs throughout most of the state. In this way, all the parties who benefit from the trials and subsequent introductions can be included in the process from start to finish. California consumers are increasingly aware of the need for environmentally sustainable horticultural practices. A large part of this sustainability is the use of plants requiring no chemical inputs and less water, mitigating the chemical load in watersheds and the waste of our precious water. The UC system — with its associated Cooperative Extension, Master Gardeners and California Center for Urban Horticulture — is ideally suited to establish and coordinate a cooperative effort with the nursery and landscape industries to introduce California native and other low-input plants to this new generation of consumers. Though this program is in its infancy, it holds great promise for fulfilling its goals of providing both producers and consumers with a large variety of beautiful plant materials, with greatly reduced negative impacts to the urban environment, for years to come.Tea is amongst the most popular beverages in the world. In addition to the provision of phenolic compounds , it is an important source of caffeine and trace elements. The quality of green tea in terms of commerce and trade is merely governed by the ratio of polyphenols to free amino acids , in addition to numerous further compounds determining the flavour characteristics. The concentration of free AA is positively associated with GT quality and accounts for 10- 50 mg g-1 dry matter in marketed GT. Free AA principally contribute to the freshness and mellowness of the infusion and their profile is dominated by the rare amino acid theanine . The flavonoids in GT, which comprise 20-40% of dry matter of young tea shoots are dominated by catechins , accounting for 10- 30 % of the dry matter. Provision of nitrogen has far-reaching consequences for the performance of plants at the biochemical, ecophysiological and ecosystem level. Nitrogen strongly affects the use of environmental resources , and in many cases a competition has been observed between N and carbon allocation, which also led to the development of theoretical concepts, like the protein competition model and the carbon/nutrient balance model addressing the functional relationship between these pools.

Green tea represents an ideal model system to study such interaction both from an ecophysiological and applied point of view. Increasing N supply significantly raised total biomass production and the yield of young shoots , although this was solely attributed to an increased number of young shoots.Total N concentration increased and C/N ratio continuously decreased with increasing N supply. The concentrations of soluble carbohydrates in roots and mature leaves were significantly reduced in response to excessive N supply, due to the demand for assimilates for nutrient uptake,drainage collection pot assimilation and growth. The accumulation of AA in young shoots depended largely on the N status, and decreased significantly in plants supplied inadequately with N. Graphical vector analysis , allowing the contribution of growth-induced dilution and concentration effects on phytochemical concentration to be elucidated, indicated that increasing provision of N led to a genuine increase of AA synthesis, and this relation was particularly explicit when analysed on a ‘per shoot basis’. The anine always remained the predominant free AA, supporting its importance in long-distance N transport in tea plants. However, while its molar share of the total AA contents initially increased from 24 to 47 % with increasing provision of N, under conditions of excessive N supply its share was reduced to 38 %. A concomitant raise of the relative contribution of glutamine and arginine that increased to 20 and 15 % of the total free AA concentration, respectively, accompanied this change, which has also been observed in previous experiments . The accumulation of these amino acids, characterised by lower C/N ratios , most likely stems from metabolic adjustments to improve the C economy, as frequently observed in other woody plants. The higher demand for C skeletons under such conditions is further supported by an increasing PEPC activity. The major catechin was epigallocatechin gallate, followed by epigallocatechin, epicatechin gallate and epicatechin. Catechin was only present at low concentrations, similar to gallic acid . Overall, individual catechins exhibited a uniform response to the N treatments imposed; hence their profile was not significantly affected. Highest concentrations of catechins were detected at intermediate N supply, while a strong reduction was noted at the highest level of N supply that also led to maximal N concentrations and lowest C/N ratios. This response has also been observed in other plant species and discussed in relation to the protein competition model and the carbon/nutrient balance . GVA clearly indicates that the total content of PP per plant increased regardless of declining PP concentrations under abundant N supply, suggesting that a dilution effect due to biomass growth is involved.

Indeed, as the yield was strongly increased at excessive N supply, the PP accumulation on a ‘young shoot basis’ was strongly diminished. With respect to substrate availability and energy the C status has been discussed as a critical factor for the accumulation of phenolic compounds . Diverting the C flux to N metabolism is therefore an important factor contributing to the observed reduction in PP accumulation, and the declining availability of carbohydrates is also analogue to substantially increased concentrations of AA, which is further supported by enhanced activities of PEPC and glutamine synthetase under abundant N supply. The precursor of the phenylpropanoid pathway, free phenylalanine , increased in young shoots in response to increasing N supply, but the magnitude of this increase was much smaller than that of the major amino acids mentioned above. Surprisingly, activity of leaf phenylalanine-ammonia lyase , the key enzyme of the phenylpropanoid pathway, increased with external N supply and plant N status, and the relation of polyphenols accumulation to the activity of PAL was negative . In fact, activities of PAL and GS were highly correlated , which is interpreted as a positive influence of N supply on overall metabolic activity, rather than a mechanistic link between PAL activity and the accumulation of polyphenols. Nonetheless, elucidating the relationships among N supply, the accumulation of flavonoids, and the activity of enzymes involved in their biosynthesis in tea awaits further investigations. The results indicate that the balance between growth and secondary metabolism in tea plants is shifted toward increasing synthesis of growth-related compounds such as amino acids and proteins, while investment of C into secondary metabolites is not changing proportionally. The quality index PP/AA decreased curvilinearly with increasing N status and the C/N ratio in young shoots. While a high GT quality is associated with a low PP/AA ratio, the accumulation of free arginine in response to excessive N supply needs particular attention due to the adverse taste notes attributed to this amino acid. The food-energy-water nexus is a concept that acknowledges that food, energy, and water systems are inextricably linked, are dependent upon one another and in concert mediate access to resources as well as resilience of human-natural systems . A constraint in one system could not only affect economic security in that system but could inhibit access in another . Therefore, the nexus provides a powerful means to improve synergies in food, energy, and water production , to identify how stressing food, energy and/or water systems creates resource vulnerabilities and/or resource scarcities in all three, to understand and quantify the production of ecosystem services, and to develop climate adaptation strategies . However, historically, food, energy, and water systems have been pigeonholed politically as well as broken up into small disjointed pieces that cross political boundaries and do not align with bio-regions or watersheds .

We therefore tested whether strain 869T2 grown at 30 ◦C could enhance the growth of different Arabidopsis ecotypes and other plant species. In addition to Arabidopsis ecotype Columbia, three Arabidopsis ecotypes that are less susceptible to Agrobacterium tumefaciens infection, BL-1, UE-1, and Dijon-G, were selected to examine the growth promotion ability of strain 869T2. After inoculation with strain 869T2, the average value of the fresh weight , dry weight , rosette diameter , root length , number of leaves , total leaf area per plant , and leaf area per leaf of the three additional Arabidopsis ecotypes were 1.2- to 2.0-fold higher than control plants. These data further support the hypothesis that the presence of strain 869T2 in different Arabidopsis ecotypes has a positive impact on plant growth.Seedlings of ching chiang pak choi and pak choi from the Brassica genus were also inoculated with strain 869T2 to examine its effects on plant growth. At 27, 33, and 40 days after inoculation with strain 869T2, the average fresh weight and dry weight of above ground leaves of ching chiang pak choi were higher than those of the control plants . Furthermore, the average leaf length and width, petiole length and width, number of leaves per plant, total leaf area per plant, and leaf area per leaf were greater in the 869T2-inoculated ching chiang pak choi compared to the control plants . The results shown in Figure 3J,K demonstrate that the average plant height and width of the 869T2-inoculated ching chiang pak choi were also greater compared to the control plants. Similarly, after the ching chiang pak choi was inoculated with strain 869T2, the average values of root fresh weight, dry weight, and length were higher in comparison to control plants . Figure 3O–Q indicate that both the aerial and below ground parts of ching chiang pak choi were larger after inoculation with strain 869T2. Figure 3R also shows that the ching chiang pak choi inoculated with strain 869T2 grew faster and flowered earlier than control plants 53 days after inoculation.

Similarly, 25 liter pot after inoculation with strain 869T2, the pak choi grew larger, including larger and more numerous leaves, larger aerial parts overall, and longer and heavier roots . These data indicate that inoculation of strain 869T2 in two vegetables from the Brassicaceae family significantly improved their growth. Because B. seminalis strain 869T2 successfully colonized Arabidopsis and two types of plants from the Brassicaceae family and promoted their growth, we further examined whether strain 869T2 could promote the growth of plants from the Asteraceae and Amaranthaceae families. At 35, 43, 50, and 56 days after inoculation with strain 869T2, the fresh weight of the aerial parts of inoculated loose-leaf lettuce plants increased 12.7- to 46.6-fold compared to the 0-day post-inoculation plants . By comparison, in the mock-inoculated control plants, the fresh weight increased 8.0- to 36.0-fold over the same period . Similarly, the dry weight of the inoculated loose-leaf lettuce increased more than that of the control plants at 35, 43, 50, and 56 days after inoculation . These data indicate that inoculation of the loose-leaf lettuce with strain 869T2 significantly enhanced plant growth. The weight increases of the inoculated loose-leaf lettuce plants were due to increases in average leaf width and length , the number of leaves per plant , total leaf area per plant and per leaf , and plant height and width . Furthermore, the root fresh weight of the inoculated loose-leaf lettuce plants increased 4.5- to 12.4-fold at 35, 43, 50, and 56 days after inoculation compared with the 0-day post-inoculation plants ; in contrast, that of the mock-inoculated control only increased 2.5- to 8.5-fold compared with the 0-day post-inoculation plants . Additionally, the root dry weight and length increased more in the inoculated loose-leaf lettuce plants than in the control plants . As seen in Figure 4M–O, overall plant size and leaf size increased after inoculation with strain 869T2, suggesting that strain 869T2 improves loose-leaf lettuce growth.

The results shown in Figures S4 and S5 demonstrate that both kinds of lettuce grew taller and wider, had more and larger leaves, and had heavier aerial and below ground tissues after inoculation with strain 869T2 compared with the control plants. The chlorophyll contents of red leaf lettuce leaves were also higher in the 869T2-inoculated plants than the control plants . These data collectively indicate that the three evaluated kinds of lettuce can grow significantly better after inoculation with strain 869T2. We also selected Chinese amaranth of the Amaranthaceae family to test the effect of strain 869T2 on its growth. At 36, 43, and 50 days after inoculation, the fresh weight of the 869T2-inoculated Chinese amaranth exhibited a 20.0- to 56.6-fold increase when compared to the 0-day post-inoculation plants, whereas the control plants only showed an 8.3- to 33.5-fold increase when compared to the 0-day post-inoculation plants . Other plant growth parameters of the 869T2-inoculated and control plants were also examined 36, 43, and 50 days after inoculation . Figure 5 illustrates that the 869T2-inoculated Chinese amaranth individuals had more and larger leaves, were taller and wider, and had heavier and longer roots than the control plants. These data show that inoculating strain 869T2 into Chinese amaranth promoted its growth.Because B. seminalis strain 869T2 promoted the growth of several leafy vegetables, we next tested the effects of the strain 869T2 on the flowering and fruit production of hot pepper and okra . Hot pepper plants, from the Solanaceae family, were inoculated with strain 869T2 but we did not observe significant growth promotion effects on the aerial and root parts of the plants. However, we did observe that the 869T2-inoculated hot pepper plants flowered 20 days after inoculation; the number of flowers continually increased and had more than a 7-fold increase at 37 days after inoculation . In the mock-inoculated control plants, we observed flowering 21 days after inoculation, and the number of flowers had only increased 5-fold at 37 days after inoculation .

The average number of fruits on the 869T2-inoculated plants was higher than that on the control plants at 30, 37, 44, and 51 days after inoculation . The average numbers of flower buds, flowers, and fruits per plant were higher in the 869T2-inoculated plants than in the control plants beginning 21 days post-inoculation . Furthermore, the percentages of hot pepper fruits with red and green/yellow coloring were higher in the 869T2-inoculated plants than in the control plants 59, 66, 73, and 80 days after inoculation . Similarly, the average anthocyanin contents of the 869T2-inoculated plants were significantly higher than those of the control plants at 66, 73, and 80 days after inoculation . However, the average length, width, and fresh weight of the fruits were not significantly different between the inoculated and control plants . Collectively, these data suggest that the inoculation of hot pepper with strain 869T2 could increase flowering and fruiting in hot pepper plants and accelerate fruit maturation.We subsequently examined the effects of strain 869T2 on okra, which belongs to the Malvaceae family. The overall plant size and weight were not significantly different between the 869T2-inoculated and control okra plants. We observed, however, that the number of nodes of the first flower was smaller in the 869T2-inoculated okra than in the control plants, suggesting that the 869T2-inoculated okra plants flowered earlier than the control plants . In addition, the average fresh weight and diameter of the fruits from the 869T2-inoculated plants were greater than those of the control plants , although the average fruit lengths were similar. These data demonstrate that the okra fruits became heavier and wider after inoculation with strain 869T2. In summary, inoculation of strain 869T2 into hot pepper and okra plants could cause plants to flower at earlier growth stages. The members of the genus Burkholderia belong to the class β-proteobacteria and have a broad distribution, residing universally in soil, water, and in association with plants, fungi, animals, and humans. Some Burkholderia species are plant pathogens in many vegetables and fruits, while others have been reported as opportunistic pathogens of humans and other animals. However, many other Burkholderia species are beneficial to plants, suppressing plant diseases and promoting plant growth by various processes, including the productionof antibiotics, secretion of allelochemicals,25 liter plant pot induction of pathogen resistance in plants, nitrogen fixation, or enhancing nutrient uptake by host plants. These beneficial Burkholderia species are free-living or endophytic and form mutualistic associations with their host plants. Burkholderia species’ high versatility and adaptability to different ecological niches rely on the high genomic plasticity of their large multi-chromosome genomes and the production of various bacteria secondary metabolites. In this study, we characterized the endophytic bacterium Burkholderia seminalis strain 869T2 isolated from vetiver grass, which was recently described and included in the Burkholderia cepacia complex . We have documented the IAA production, siderophore synthesis, and phosphate solubilization abilities of B. seminalis strain 869T2. Inoculations of strain 869T2 into tested plants demonstrated the plant growth promotion ability of this bacterium in several plant species from the Brassicaceae, Asteraceae, and Amaranthaceae families. Plant endophytic bacteria can increase the nutrient uptake and biomass accumulation of host plants through the production or regulation of various plant hormones, such as auxin, cytokinin, gibberellins, and ethylene. Indole acetic acid is a naturally occurring auxin produced by several endophytic bacterial species through the L-tryptophan metabolism pathway. Tryptophan can exist in the exudates of plants and is utilized by the bacteria to synthesize auxin, which enhances the growth of host plants. Auxin is the major plant hormone that regulates various aspects of plant growth and development, such as root initiation and development, leaf formation, fruit development, floral initiation and patterning, phototropism, and embryogenesis.

Several plant-growth promoting bacteria can synthesize IAA, including Bacillus, Burkholderia, and Pseudomonas species. In this study, Burkholderia seminalis strain 869T2 was able to synthesize approximately 2.0 to 2.2 µg mL−1 IAA in the presence of tryptophan and increased both the above ground and below ground biomass of tested plant tissues. Several previous reports also demonstrated that low levels of IAA stimulated primary root growth. Similar to our observations, the Burkholderia sp. SSG that was isolated from boxwood leaves produced 2.9 to 4.5 µg mL−1 of IAA with tryptophan and had plant growth promotion ability in three boxwood varieties. Additionally, Burkholderia phytofirmans strain PsJN, which was isolated from onion roots, showed higher IAA production, around 12 µg mL−1 , with the addition of tryptophan and improved the growth of potato, tomato, maize, and grapevines. Other Burkholderia seminalis strains can also synthesize IAA and have been reported to increase rice and tomato seedling growth. These previous studies, along with our observations, suggest that B. seminalis strain 869T2 may be similar to other Burkholderia species and other plant-growth-promoting bacteria that utilize IAA to increase root growth, which may assist host plants in taking up nutrients from the surrounding environment and improve aerial tissue growth. Consistent with this hypothesis, we observed that plant size, height, fresh weight, dry weight, and total leaf areas of several tested plant species all significantly increased after inoculation with B. seminalis strain 869T2. It is known that the IAA can positively affect cell division, enlargement, tissue differentiation, root formation, and the control process of nutrition growth. The IAA can also function as a signal molecule to influence the expression of various genes involved in energy metabolism and other plant hormone synthesis, such as gibberellin and ethylene. Interestingly, we observed earlier flowering in the 869T2-inoculated hot pepper and okra plants, suggesting that acceleration of plant growth rates might occur in these plants. In the future, transcriptome analysis of plant hormone response genes and energy-metabolic-related genes in the 869T2-inoculated plants might help us further decipher the possible mechanism of plant growth promotion ability of strain 869T2. From the results of our study, we observed that B. seminalis strain 869T2 had a better IAA yield at a temperature range of 25 ◦C to 37 ◦C and pH of 6 to 9. Similarly, Burkholderia pyrrocinia strain JK-SH007 reached the maximum production of IAA at 37 ◦C and pH 7.0.

A recent report shows that transient expression of the type three effector of Salmonella 14028 SseF in tobacco plants elicits HR, and this response is dependent on the SGT1 protein . This study suggests that SseF can induce resistant-like response in plants and requires resistance protein signaling components. Üstün et al. and Shirron and Yaron also showed that Salmonella 14028, which is able to deliver the SseF effector, cannot induce HR or any disease-like symptoms in tobacco leaves. Thus, it remains to be determined what would be the biological relevance of ETI in the Salmonella and other human pathogenic bacteria in their interaction with plants in nature.Although S. enterica and E. coli O157:H7 have not been traditionally known to be closely associated with plants and modulate plant’s physiology, the evidence tells us otherwise. An arms-race evolution in both the human pathogen and the plant is therefore, expected. A few studies have addressed whether genetic variability among plant species or within the same plant species can be correlated with differential bacterial behavior and/or colonization of plants. Barak et al. described that different tomato cultivars can harbor different levels of S. enterica population after inoculation via water indicating plant factors may control the ability of bacterial to colonize the phyllosphere. However, they also found that the cultivar with the smallest S. enterica population also had the lowest number of speck lesions when infected with the tomato pathogen Pst DC3000 , suggesting that strong basal defense in this cultivar may account for low bacterial colonization. On a comparative study of S. enterica contamination of several crop species, Barak et al. reported that seedlings from Brassicaceae family have higher contamination than carrot, tomato,vertical farming equipment and lettuce when grown on contaminated soil.

Seedling contamination correlated with the Salmonella population in the phyllosphere of all crop species, except tomato. Golberg et al. reported variations in internalization of Salmonella SL1344 in different leafy vegetables and fresh herbs using confocal microscopy. Internalization incidence was high in iceberg lettuce and arugula, moderate in romaine lettuce, red lettuce, basil, and low in parsley and tomato. Attraction to stomata was seen in iceberg lettuce and basil, not in arugula, parsley, and tomato. Brandl and Amundson reported that the age of romaine lettuce leaves is correlated with population size of E. coli O157:H7 and S. enterica Thompson on leaves.These authors also observed that exudates on the surface of younger leaves have higher nitrogen content than that of older leaves, which may contribute to determining the bacterial population size on the leaf. Thus, it is tempting to speculate that the genetic variability existent among plant genotypes regarding the chemical composition of their organ exudates may be a determinant for human pathogen behavior and ability to colonize plants. Finally, Mitra et al. studied the effect of different methods of inoculation on internalization and survival of E. coli O157:H7 in three cultivars of spinach. Among the organs studied, the spinach phylloplane and the stem provided the most and least suitable niche for this bacterium colonization, respectively. Although the leaf surface was the best “territory” for E. coli, the leaf morphologies of each cultivar affected the ability of this bacterium to survive. Collectively, all these studies point out that the plant genotype, age, leaf morphology, chemical composition of exudates, and the primarily infected organ affect the outcome of bacterial colonization of plants and the process may not be a generalized phenomenon, consequently shaping specific human pathogen and plant interactions.

For the past 43 years, people from across the U.S. and around the world have come to UC Santa Cruz to learn organic farming and ecological horticulture skills and concepts. What began in 1967 as the UCSC Student Garden Project, an informal student apprenticeship with English gardener Alan Chadwick, has since grown into the internationally known Apprenticeship in Ecological Horticulture, offered each year through the Center for Agroecology and Sustainable Food Systems . The six-month, intensive program combines hands-on and classroom work, covering topics ranging from soil fertility management, crop selection and culture, pest and disease management, and greenhouse and irrigation skills, to business planning, marketing, and food system issues. Apprentices work alongside instructors, learning in an “I do, we do, you do” model at the 25-acre UCSC Farm and 3-acre Alan Chadwick Garden. Since its founding, more than 1,300 people have graduated from the Apprenticeship, and have gone on to a variety of careers in sustainable agriculture and food systems-related work. Although CASFS staff members have informally tracked the activities of the Apprenticeship program’s graduates, there has never been a formal survey to find out how Apprenticeship alumni are applying their training and how the program has contributed to their work, volunteer, and personal activities. In 2009 CASFS undertook a comprehensive survey of alumni both to document the impacts of the program and to get suggestions for ways to improve the Apprenticeship. The survey was designed to address two basic questions: Is the Apprenticeship contributing to a more sustainable food system? To what extent did the program contribute to alumni’s activities? A grant from the Foundation for Global Community provided support for the survey and analysis.

The survey found that program graduates are making a major contribution to creating a more sustainable food system. This is reflected in the significant number of alumni involved in a wide range of sustainable food and agriculture efforts, and particularly in teaching others about food production and sustainable food systems. This brief summary provides an overview of the Apprenticeship alumni survey methods and results. A series of graphs detailing the results, with a focus on what all of the respondents have been doing since graduating from the program, is available online at the CASFS website.a A more in-depth analysis of the results and implications for education are presented in, “Achieving Program Outcomes? An Evaluation of Two Decades of Apprenticeship in Ecological Horticulture at the University of California, Santa Cruz Farm and Garden,” by CASFS researcher Jan Perez, UC Davis postdoctoral student Damian Parr, and UCSC graduate student Linnea Beckett, which appears in the inaugural issue of the Journal of Agriculture, Food Systems and Community Development.The survey was designed collaboratively with CASFS staff and input from alumni. Overall, 23 alumni and others pretested versions of the survey. The final survey included both quantitative and open-ended questions. All past apprentices since the founding of the program in 1967 comprised the survey population for the project; this included an estimated 1,200 alumni as of the survey date. The survey was sent to the 648 alumni for whom there was a known email address, drawn from an alumni database that was created in 1997 and updated recently for fundraising efforts and alumni activities. The survey was implemented between June 18 and July 20, 2009.The survey drew a response rate of 60% , which is considered high for a self-administered survey. Approximately 25% of graduates in each class since 1989 responded, with the most responses from those who had graduated in the past 10 years. Respondents were generally European-American, under 30 years of age during their Apprenticeship, from a middle-class or upper-middle class background, and had a 4-year college degree when they started the program .Since finishing the Apprenticeship, 87% of respondents are currently or have been involved in the field of sustainable agriculture and food systems work . Eighty percent volunteered for activities that contribute to sustainable food systems, and 99% used what they learned during the Apprenticeship in their personal lives. In addition, 48% of the alumni from the past 20 years had initiated, created,macetas para fresas or started the work or effort in which they were involved, which speaks to the leadership role that many have assumed since graduating .d Of the 315 respondents who are or have been involved in sustainable food and agriculture work, 93% reported doing some type of farming or gardening work since graduating. Primary job areas include food production , education , landscaping/gardening , retail , and work with non-governmental organizations . People have worked in rural , urban , and peri-urban settings, with many alumni having worked in more than one place since graduating. Two hundred of the respondents reported owning or operating a farm or garden at some point since graduating. Of those people, most grow a mix of vegetables and fruits; they also produce flowers , fruit , animal products , and grain , while 12% are involved in animal production. Those who own or operate a farm or garden employ one or more distribution strategies. These include direct sales to stores or restaurants , farmers’ markets , community supported agriculture efforts , wholesale , farm stand , and farm-to-institution . In addition, 40% donated produce as part of their operation.Education plays a role in the work of a significant number of alumni: 64% of all survey respondents, and 74% of those working in sustainable food and agriculture, reported that they have had jobs that included education activities or programs—particularly around food production and food systems issues and knowledge—as part of their formal goals.

In addition, 55% of those involved in education state they are training future teachers and trainers of sustainable food and agriculture-related topics. These “training the trainer” efforts increase the impacts of the Apprenticeship far beyond those who graduate each year. In terms of influencing social justice, the survey asked alumni if they had attempted to implement various strategies into their sustainable food and agriculture system work, volunteer, or personal activities. Among the responses, 60% reported that they had attempted to increase access to healthy food for those with limited access; 56% had increased inclusion; 48% had addressed inequities in access to information; 45% had fostered sharing of power or ownership; and 41% had increased the income of small- and mid-scale growers. Since these activities could range from buying fair trade coffee to starting a non-profit, we also explored this issue more specifically. We looked at work, volunteer, and personal activities people listed, and identified when they included addressing needs of people who were traditionally under served, worked on hunger or food security issues, or used words such as just, fair, and diversity. At least 35% of the respondents met these criteria. In addition to work endeavors, 80% of alumni have been involved in volunteer activities related to sustainable agriculture and food systems. Thirty three percent report donating time or materials to gardens, farms, schools, and outreach efforts; 28% have been involved in alternative agriculture organizations, as either founders, board or committee members, or as participants in activities; and 17% have led programs, classes and workshops, or served as a mentor. Other volunteer activities include community organizing and international community service . The Apprenticeship has also had an impact on alumni’s personal activities. Fifty-two percent report that the Apprenticeship influenced their purchasing behaviors, including buying local, organic, fair trade, and seasonal foods, as well as supporting farmers’ markets, CSAs, and local farms. Other personal activities include growing their own food or helping others grow food , and educating others .When asked how the Apprenticeship contributed to their subsequent activities, the majority of respondents noted that the program provided knowledge and skills . Survey respondents also reported that the program significantly helped them confirm their values ; provided confidence in their skills and ability ; helped shape their career goals ; and provided a network of people/contacts . Program components identified as most helpful for contributing to Apprenticeship graduate Cathrine Sneed launched The Garden Project to serve former offenders. Today the San Franciscoarea program provides on-the-job training in gardening and tree care. Apprenticeship alumni Jered Lawson and Nancy Vail founded Pie Ranch near Pescadero, California. The educational farm connects urban and rural high school students with the source of their food and provides training in farming skills. alumni achievements are described in Perez, Parr and Beckett .f Based on responses from the last 20 years of graduates, 60% of alumni considered the “hands-on” emphasis to be important to helping them accomplish their post-graduation activities. The next most-cited important program components were the residential living aspect of the program , working with peers , course work , and working with teachers .g This survey confirms that many alumni are participating in creating more sustainable food systems in a variety of ways, including farming, gardening, and educating others.

The primary trade-off here is that xESM provides a higher fidelity model for multi-segmented missions given that it includes the costs for all mission segments where an item is carried, while the ALSSAT’s ESM calculation method does not include preceding mission segments ALSSAT. This result is especially important considering downstream bio-manufacturing options which show a reduced xESM metric in scenarios where predeployment is leveraged to reduce the cost associated with the transit. Additionally, our “bring everything” mission which does not rely on bio-manufacturing yields larger costs overall from increased stored food. All three scenarios have equivalent tr2 ESM and xESM; this shows that in the last leg of the journey, or in a segment that is not influenced by future operations, ESM equals xESM. While simplified, this captures many of the critical features necessary to demonstrate the need for ESM extension. In cases where inventory from one segment can be used to satisfy constraints in another segment, the ESM summation of separately optimized mission segments can be less optimal than an ESM optimized with an objective function that accounts for both segments and constraint functions containing both terms from both segments. Given that system mass analyses are often used in the preliminary evaluation of technologies, it becomes more important when considering bio-manufacturing platforms to leverage the xESM formulation to provide higher fidelity and more favorable metric. However, we also must clarify that the aim of exploring this example is not to make claims about a specific technology,hydroponic vertical garden but rather to provide an example for differentiating ESM and xESM.

So far, we have looked at the xESM framework for calculating segmented costs. Based on the scenario chosen, the xESM metric is ultimately determined based on some set of specific technologies that are used. Simpler cases, as the ones given in the examples assume that the behavior of a particular system is fully known on Mars and the operation of the systems is undisturbed by external factors. Although several systems can reliably be considered deterministic in this scope, effects such as micro-gravity might affect the dynamics of specific processes in a bio-manufacturing context. Moreover, each process possesses a set of faulty states, i.e., technical issues may cause a system to underperform significantly. Detailed analysis of novel systems, e.g., in the bio-manufacturing case, requires the description of the operation of systems using mathematical models. To this end, the xESM framework can be used both to analyze the cost of individual processes as well as the cost of integrated processes in any desired segment, as they operate in time. A simulation-based analysis, either some cost analysis of specific elements or some end-to-end optimization procedure, makes use of models to simulate the systems, the environment, and associated costs for achieving the mission objectives. As a remark, we should note that the sophistication of the simulated case study can vary. For instance, higher-level decisions can be optimized without the need for detailed models for individual components, while exact scheduling and operational decision-making should involve dynamical models for the various subsystems. This principle has been widely adopted in manufacturing settings for design and control. Parts of the costs not commonly accounted for in cost calculations for space missions like ESM are uncertainty and risk. The latter are important factors during the design phase as we need to ensure safety in a robust, worst-case setting.The use of the xESM framework helps guide the development and implementation of software for a reference mission architecture for long-duration human exploration of Mars. We recognize that this extension of ESM as a metric for mission scenario comparison is preliminary and not exhaustive in its scope.

We also note that no single analytical result such as ESM or xESM will be the sole factor in the technical specification or platform decision-making. The differences presented are important but modest and are in scale with the uncertainty of the quantities used as the inputs. In addition to the incorporation of mission parameters, specific constants and terms in our formulation are required, such as a more precise calculation of equivalency factors for cooling, power, volume, and crew time and distillation of the specifics for risk fractions. Future endeavors include a comprehensive optimization problem formulation and solution based on the xESM framework both for biologically and non-biologically driven missions. Moving forward, we hope that our extension of ESM provides the basis for continued systems engineering and analysis research for a more quantitative and inclusive design and optimization of long-term human exploration missions.Calcium in plants has essential roles affecting tissue mechanical strength and tolerance to biotic and abiotic stresses . Understanding Ca translocation and partitioning to the different plant parts with time and the factors affecting it has a high agronomic and economical value as it will allow improving Ca nutrition practices to give higher quality end products. Ca was shown to accumulate mainly in transpiring organs in a process affected by various environmental conditions at both the canopy and root level, and is considered to be coupled to water movement driven by transpiration although controversies still arise in that relation . Furthermore, as Ca moves mainly in the xylem, a transport conduit under negative pressure, any attempt to sample it en-route will cause cessation of flow. As a result, the use of cumbersome destructive methods, which has limited research scope due to time and space constraints, has brought only fragmented and/or circumstantial evidence . For example, using pressurized stem exudation and leaf bleeding Siebrecht et al.showed either diurnal pattern or spatial distribution but not both together. Looking into various nondestructive methods it was found that Ca nuclides are either incompatible or inapplicable.

As Strontium was found to behave in similar ways in plants as well as in the more complex environment of human clinical research , it was chosen to serve as Ca tracer. Having a high energy gamma emitting nuclide that can be detected outside the plant, remote sensing became feasible. Tomato plants were grown in the phytotron of the Hebrew University under controlled climate of day/night temperatures of 28/18°C and RH of 40/65% respectively. Each plant was grown in a 5 L container containing half-strength modified Hoagland solution and was continuously aerated. After three months, reaching approximately a height of 1.60 m and having three fruit bearing trusses, eight plants were transferred each to a 2 L cylinder filled with nutrient solution and moved to a growth room subjected to temperature of 24/16°C and RH of 40/80% during the day and night respectively. Air temperature and RH at plants vicinity were recorded continuously and VPD was calculated according to Lowe . Light was supplied between 08:00 to 20:00 by two cool mercury lamps at 400 µmole m-2 s -1 PAR. Plants were arranged in four pairs with the 1st plant of each pair placed on a weighing lysimeter and monitored continuously with momentary whole plant transpiration derived from weight loss. The 2nd plant was installed with an array of five gamma radiation detectors ,vertical vegetable tower each with a custom-made lead shield. The shielded detectors were mounted on a moveable platform positioned to target the following locations: 1) main stem below the 1st fruit truss; 2) main stem below 2nd fruit truss; 3) main stem below 3rd fruit truss; 4) first fruit of 2nd truss; 5) leaf petiole adjacent to 2nd fruit truss. The detectors were connected to a PC via a custom-made communication device and radiation activity was measured continuously. More details of the system can be found in Wengrowicz et al. . Radiation readings were resampled to one minute and filtered in parallel to the transpiration data to eliminate noise. After three days of acclimatization, radio-Sr solution with an activity of 0.25 mCi was diluted in 10 mL of distilled water containing 4 mM Sr 2; Merck, Germany and added to the nutrient solution of the 2nd plant around noon.Every few days the radiation measuring system was detached and moved to the 2nd plant of the next pair. An example of radiation readings from one plant on the day of application is shown in Fig. 1. Within 30 minutes after adding the mixed Sr and radio-Sr solution to the nutrient solution, a sharp increase in radioactivity was noticed in the lower-most stem detector . A similar pattern yet with about half the rate was observed 30 minutes later in the middle stem detector and another 30 minutes took the radio-Sr to reach the upper-most stem detector with half the rate of the previous. Starting at the top of the plant root system and accounting for the distances between the detectors along the stem, radio-Sr velocity is estimated to be 0.154 mm s-1 , 0.143 mm s-1 and 0.125 mm s-1 at the 1st, 2nd and 3rd stem detectors respectively. Fruit and leaf petiole detectors showed a slow radiation increase and as no clear arrival time was seen, velocity could not be defined. To emphasize changes in radiation activity, and omit background levels, time derivative of radiation readings were calculated. On the day following application , radiation rate increased already before lights were switched on , starting at the low stem detector and followed by middle and top stem detectors around 03:10, 04:20 and 05:30 respectively. Fruit and leaf petiole radiation rate increased around the same time however with a much lower rate. Initial daily rate was highest at the lower-most stem detector and decreased the further the stem detector was from the source, with fruit and leaf petiole the lowest.

Maximum rates were achieved around 10:00 following the same order of both timing and rates, excluding the fruit detector which showed a 2-fold rate compared to leaf petiole. Thereafter radiation rates dropped quickly only to show a 2nd smaller wave peaking towards 18:00 and subsiding towards evening. A third wave was clearly observed at the three stem locations after lights were switched off, with rates decreasing the further the detector is from the source. Transpiration rate pattern of a neighbor plant showed low rates during dark periods except from a noticeable swell starting around 03:30. During light hours, a rate increase with three distinct peaks can be seen which correlated nicely with room VPD . It should be noted that transpiration rate correlated with radiation rate patterns only until the 10:00 peak, suggesting thereafter a more complex relationship between sap transport and radio-Sr translocation. As time passed, radiation readings at the top-most stem, fruit and leaf petiole detectors increased. The middle stem detector showed in-large a saturation curve pattern, while the lower-most stem sensor, which measured the first few days the highest radiation increase, showed later a decline to level lower then those detected at above stem positions . To shed some light on the accumulative patterns, radiation rates on the 10th day after application are presented in Fig. 4. Lower-most stem detector exhibited negative predawn and morning rates yet a morning peak was still present. Rates climbed slowly towards zero during light hours and proceeded with an after-dark positive peak. The middle stem detector showed a similar pattern although being positive till the predawn drop to later “surface” above zero in the afternoon. The top-most stem as well as fruit and leaf petiole detectors showed positive rates throughout the day with a similar pattern as the other stem detectors. The sequential arrival of root applied radio-Sr to stem locations on the day of application clearly maps its flow path, whereas its decreased velocity along it suggests sap loss as it is being directed towards side organs as leaves and to a probably lesser extent, fruit trusses. As radio-Sr translocation rates were also reduced along the path, it is assumed that Sr was embedded in plant tissue, absorbed on cation exchange sites, and/or unloaded off the xylem causing sap Sr dilution. Throughout the following days, daily transpiration rate showed predawn increases with a possible link to circadian stomata opening resulting in a sap flush within the plant. Predawn translocation rate pattern depended on time that passed from application and detector location. On the first days, when Sr was still accumulating on available cation exchange sites within the stem tissue, translocation rates exhibited significant increase at all locations.

In separate studies NPR1 over-expression and enhanced resistance are correlated either with elevated or earlier expression of PR gene transcripts, thus supporting this theory . Along with stimulating PR gene expression and priming plants to respond to infection, high NPR1 expression levels enhance the sensitivity of plants to chemicals and fungicides including BTH, fosetyl, and Cu2 . NPR1 is also required for a BTH-induced defense priming indicating a great potential for coupling both chemical and transgenic disease strategies through plants expressing NPR1 . For instance, plants can be engineered to over-express NPR1 so that a lower chemical dose is required to confer efficient disease resistance. Genes with high sequence similarity to NPR1 can be found in Arabidopsis, tobacco, tomato, rice and maize suggesting that this regulator will be conserved among many plant species. Over expression of NPR1 in rice has been shown to enhance resistance to the rice bacterial blight pathogen Xoo . Studies with a putative rice homolog of NPR1 indicate that over-expression of the endogenous rice gene can also provide protection against Xoo . However, unlike in Arabidopsis, rice over-expressing NPR1 grown under sub-optimal conditions display a detrimental growth phenotype. These types of observations may predict an overall phenotype that will need to be further investigated when strongly over-enhancing SAR pathway components in plants . Together these data suggest that, in general,growing vegetables in vertical pvc pipe crop plants contain defense signaling components similar to those found in Arabidopsis.

Potentially, over-expression of other endogenous signaling components other than NPR1 may also be able to provide enhanced plant protection.Biotic infections that stimulate localized host cell death can stimulate SAR in a wide variety of plants, as indicated above. Similarly, root colonization by non-pathogenic Rhizobacteria, can stimulate induced systemic resistance . This resistance is distinct from SAR, but interestingly shares one of the same components, NPR1and can work additively with SAR to mount a heightened defense response . Induction of the ISR response requires that plants are able to properly respond to signals triggered by JA and by the plant hormone ethylene. ISR is not functional in Arabidopsis mutants that are nonresponsive to ethylene, although the SAR response remains intact . Presently, most work utilizing ISR with field grown crops focuses on bio-control. For example, when tomato plants or seeds are treated with dried Rhizobacteria spores, the severity of infection by the tomato mottle virus is reduced . It is notable that the ISR pathway shares components with other defense pathways. Thus, altering the amount of a single component involved in multiple pathways, such as NPR1, may have unintended pleiotropic effects, both favorable and unfavorable that will need to be addressed before application in the field. Plants induce defense responses not only against bacterial, fungal and viral pathogens but also against pests that can cause wounding. Thus, other biotic inducers of resistance include herbivorous insects. The chemical JA is important for triggering resistance to these pests . The defense pathways controlling insect defense and other induced responses are partially antagonistic.

Treatment of plants with SA and BTH can inhibit the induction of JA induced genes and conversely, application of JA reduces the defenses triggered by ISR inducers . However, it appears that the SA and JA pathways can also, in some situations, act in concert to promote defenses against at least a subset of pathogens. In Arabidopsis, in studies where both SA and JA are applied to a plant these chemicals can work additively to protect plants against Pseudomonas syringae pv. tomato . Potentially, upregulation of one induced resistance pathway may impart costs to a number of other pathways. With such complexity inherent in defense responses, it becomes clear that thorough field tests performed under multiple environmental, developmental and pathogen stressors will be essential for any plants engineered for enhanced resistance.Basic research is providing an ever-expanding arsenal of genes with which to engineer disease resistance. Several of these genes have already proven useful and more will undoubtedly be discovered. However, the limitations and costs to using this technology are just starting to be explored. A thorough understanding of these areas will be increasingly important as the tools identified by basic research in plant defense mechanisms are applied more frequently to commercial crops. Previously, only a few studies have attempted to look at the costs, for example, in fitness to plants induced for one of these resistance responses and even fewer still of these studies have been with the economically important cereal crops .Most of the genes involved in broad-spectrum resistance have yet to be inserted as transgenes into crops. Therefore, investigations into the costs of induced resistance have started by assaying the effects of using chemical inducers. Heil et al. have studied the fitness of wheat plants treated with BTH in the absence of pathogens.

When plants were grown either hydroponically or in the field, water-treated control plants were able to achieve greater biomass than their BTH-treated cohorts. In field experiments, however, significant growth differences were not seen until approximately 6 weeks after treatment. The authors suggest that many of the potential fitness costs associated with induced resistance responses may be masked in laboratory experiments where growth conditions are kept optimal, and support this hypothesis with experiments performed growing plants under differing nitrogen concentrations. In addition, when the age of the plants induced for SAR was considered it was found that the growth-costs of BTH treatment could be reduced if the BTH was applied after the lateral shoot formation was complete . These data also underscore the importance of factoring plant developmental programs into any efficient strategy to enhance plant resistance by chemical treatment or genetic engineering.Another unwanted effect that may arise from transgenic manipulation of genes involved in defense signaling pathways is spontaneous cell death. Spontaneous cell death has been uncovered in many genetic screens for enhanced disease resistance and recently, has been seen in transgenic plants. These mutants and transgenic plants are often collectively referred to as lesion-mimic mutants since they display lesions similar to those observed in a defense response even in the absence of pathogens. This form of cell death in plants is sometimes influenced by alterations in environmental conditions such as light, temperature and humidity . Therefore, both in basic research and in applied experiments, it will be important to understand the parameters controlling cell death. This research is critical not only for optimizing the situations where transgenes and chemicals will be most useful to generate disease resistance, but also to minimize negative effects on important agronomic factors such as development,vertical greenhouse fertility and yield. Several dicot lesion-mimic mutants that lead to enhanced cell death have been well characterized including the Arabidopsis acdand lsdmutants . A recessive mutation in the LSD1 gene leads to a lesion-mimic phenotype that is triggered under long-day light conditions and by treatment with SA and INA .

The lsd1 mutation appears to confer hypersensitivity to these compounds . It is hypothesized that reactive oxygen species accumulate in leaf tissues preceding formation of lesions and that LSD1 normally functions to define the extent of lesion spread by suppressing cell death . ROS accumulation is observed in the initial stages of plant defense responses including during the hypersensitive response . In wild-type plants, the HR precedes the formation of micro-lesions that are correlated with induced resistance and is associated with subsequent resistance to pathogen infection . Altered accumulation patterns of ROS in plants with heightened cell death or an HR suggest that ROS play a central role in regulating plant programmed cell death . Lesion-mimic mutants have also been identified in cereals including rice, maize and barley . In rice, one well-characterized class of lesion-mimics contains the slmutants . Many of the sl mutants display heightened resistance to M. grisea and increased expression of PR-1 and peroxidase genes . Other rice lesion mimic mutants displaying enhanced resistance are the cdrmutants . The cdr mutants also have elevated PR gene expression and cell cultures of the cdr mutants under certain conditions can accumulate H2O2. Thus, a subset of rice lesion mimics may have misregulated levels of ROS . Misregulation of ROS accumulation also occurs in transgenic rice engineered to express the OsRac1gene. Over expression of OsRac1 in a wild type stimulated H2O2 accumulation in leaf tissue and over-expression in an sl background stimulated cell death . While mutant rice genes leading to lesion-mimic phenotypes have only been hypothesized to play a role in ROS regulation, one lesion-mimic-inducing gene from maize, Les22, has been cloned. Les22 encodes a uroporphyrinogen decarboxylase , an enzyme required for chlorophyll and heme biosynthesis . Mutations in the homologous human enzyme lead to the light-induced skin toxicity condition of porphyria. People with mutations in the UROD are predicted to accumulate high levels of uroporphyrin III that upon light excitation can become highly reactive resulting in toxic levels of ROS. While the Les22 mutant phenotype does not appear to be associated with enhanced resistance to pathogens, a recessive Les mutant, les9, displays enhanced resistance to the pathogen, Bipolaris maydis . Another maize lesion-mimic mutant, lls1 , a recessive mimic mutation is associated with enhanced resistance to the maize rust fungus, Puccinia sorghi . The LLS1 gene was cloned and found to encode a novel protein containing two binding motifs resembling aromatic ring-hydroxylating dioxygenase regions suggesting that this gene may also be involved in detoxification, perhaps of a phenolic compound important in mediating cell death . Finally, pathogen resistance is associated with lesion-mimic phenotypes in not only rice and maize, but also barley.The mlo mutation confers a spontaneous cell death phenotype upon pathogen challenge and noticeable formation of structural appositions under epidermal cells. Thus, the mutant phenotype confers a rapid death phenotype to the cells, halting fungal ingress at the point of challenge and preventing a compatible interaction. The wild-type allele MLO prevents cell death when challenged by E. graminus . Many mutants showing lesion-mimic or enhanced cell death phenotypes are associated with enhanced disease resistance. This does not necessarily suggest that cell death is a requirement for defense, or that defense always de-represses cell death pathways. Simply, many defense components will likely have multiple roles in basic metabolism and stress responses throughout the plant that need to be characterized before utilizing these genes for resistance engineering.Many of the examples listed above, may appear as substantial challenges to engineering disease resistance, however, these challenges provide opportunities to create plants that are even more resistant than plants engineered based on our current knowledge. For instance if the already identified components of a signaling pathway are not the best candidates for durable resistance in the field, technologies such as micro-arrays will help to pinpoint novel targets of interest . When mutations involved in disease resistance have already been identified, but are recessive in nature such as the mlo, edr1 and mpk4 mutants, classical breeding strategies can be employed. These mutants cannot be placed into heterologous systems using transgenic technology but, as with gene-pyramiding, they are still useful in breeding. Or, as technology continues to improve, gene knockouts and silencing of homologs may be employed to generate mutants in diverse species. If research continues to suggest crosstalk between ISR, SAR and insect defense signaling pathways, there may be great potential for additive defense effects by manipulating overlapping components. So, while limitations and cost of engineering broad-spectrum defenses warrant much attention, it is useful to look at such challenges as means for streamlining and improving upon current engineering strategies.Another promising strategy for enhancing resistance in plants is the use of RNA homology-dependent silencing to combat viral and bacterial disease . The nature of this silencing has been evaluated in a number of systems where similar phenomena are called by different names; RNAi in animals and quelling in fungi . One conserved step leading to RNA homology dependent silencing is the formation of a double stranded RNA intermediate. This dsRNA intermediate is recognized by an enzymatic complex which targets degradation of all corresponding homologous RNA transcripts . Several cases detailed below illustrate the possibilities for generating disease resistant plants by taking advantage of this inherent biological process.

Synthesis of malate, however, may unduly tax a carbohydrate-limited root apex. Indeed, Ca2 treatment, which accumulated more NO3 – than the other treatments , contained negligible amounts of malate . In conclusion, NH4 + and NO3 – differentially affect the finescale spatial patterns of uptake, export, assimilation, and carbohydrate content along root apices. Moreover, although NO3 – levels are maintained low in the meristem and the apical part of the growth zone, NO3 – clearly needs to be considered as a significant component of the osmotic pool supporting expansion at the base of the growth zone and sustaining the functions of young, mature root tissues.Unlike most commonly occurring coconuts, the edible solid endosperm often called the ‘meat’ or ‘kernel’ is thicker, with a soft jelly-like texture at maturation. This can be attributed to some unusual physiological and bio-chemicaltraits. Makapuno contains high levels of cytokinins which promotes cell proliferation and expansion that results in greater endosperm thickness compared with normal coconuts . The unlimited growth of the solid endosperm makes Makapuno a model system for tumorigenesis studies in higher plants . Makapuno also lacks – galactosidase activity which leads to the accumulation of higher levels of the water-soluble galactomannan rather than the water insoluble mannan found in normal coconuts . This likely alters cell wall structure and adhesion and produces a highly viscous endosperm . Finally, Makapuno has a higher content of moisture and protein in the endosperm but lower crude fat; the latter trait should reduce rancidity which is important to those food processing industries that use coconut in their products .

These features of the Makapuno coconut are similar to ‘Kopyor’ in Indonesia, ‘Dikiri Pol’ in Sri Lanka, ‘Thairu thengai’ in India , Maphrao Kathi’ in Thailand and Dua Dac Ruot in Vietnam ,vertical planters for vegetables and are all known for their combination of good taste and unique ‘meat’ texture .The unique endosperm of Makapuno may be controlled by a single Mendelian recessive mutation . The described traits are only found in the triploid endosperm and all alleles need to be recessive. Makapuno therefore need to be physically segregated from normal coconut trees to prevent cross pollination. In addition, the highly viscous nature of the inner endosperm makes germination difficult. The need for a triploidhomozygous recessive state and the observed low germination frequency makes Makapuno coconuts a rarity in nature. The result is a sale price that is 3–5 times higher than normal coconuts in South East Asia and that can be 50 times higher than that of normal mature coconuts in Thailand. Although Makapuno is a value-added commodity,to our knowledge, the post harvest behavior of its fruit has not yet been studied. This is important because of the increased demand for fresh coconut fruit in distant markets in Europe and the United States . Previous work showed that normal mature coconut can be stored for 3–5 months post harvest under ambient atmosphere, after which, the liquid endosperm evaporates and the embryo germinates . De-husked mature coconut has a shorter storage life: up to 2 months at 0–1.5 ◦C, or 3 weeks at 12–15 ◦C . Although removal of the husk reduces shelf-life, the cost-benefit analysis is better. These fruit weigh less which lowers long-distance shipping costs and the price can be marked-up as the product is more convenient for the consumer. As described, Makapuno fruit has distinct properties compared to normal coconuts and this would be expected to influence the storage performance and conditions used to maintain its quality.

The overall goal of this study therefore, was to provide basic information on the storage conditions needed to prolong Makapuno coconut storage-life.Fully mature Makapuno coconuts were partially de-husked, leaving a layer of fiber 1–2 cm thick and were transported from Kanchanaburi province to the laboratory at Kasetsart University within 2 days of harvest. Six uniform and damage-free coconuts were packed in strong well ventilated fiberboard cartons with dividers to separate individual fruit and were then stored at 30 ± 2 ◦C, 66 ± 5% relative humidity . Individual fruit was examined for respiration rate, ethylene production rate, weight loss, color, total soluble solid contents , titratable acidity and lipid oxidation of coconut meat expressed as malondialdehyde values and decay at the initial day and 3 days after storage.The overall aim of this work was to determine the conditions necessary to extend the storage life of partially de-husked Makapuno coconuts after harvest. Our observation of Makapuno coconut maturation agreed with the findings of Islam et al. . Makapuno coconut reached early maturation ∼9 months after flowering and became fully mature ∼10–11 MAF. The endosperm is thicker and softer than that of normal coconut and the liquid endosperm filled the rest of cavity. Our data showed no significant difference in respiration and ethylene production of Makapuno coconut harvested between 9 and 11 MAF .Since there are no published data on the post harvest biology of Makapuno that we are aware of, this work is the first evaluation of the compositional, physiological and biochemical changes in Makapuno coconut fruit after harvest. During 3 days of storage at 30 ◦C, the rates of respiration and ethylene production for Makapuno were similar to those reported for normal mature coconut genotypes . However, the respiration rate from disks of Makapuno coconut was found to be higher than that of intact whole fruit.

This may be due to differences between whole fruit and disks in term of the amount of surface area exposed to the atmosphere or the gas transmission and gas solubility through the tissues. Post harvest fruit quality can be partially assessed by evaluating SS, TA and weight loss. The SS of de-husked normal coconut declines but TA increases as the post harvest storage period increases . Normal harvested mature coconuts lose weight gradually over the storage period due to water evaporation from the fruit cavity or due to absorption by the kernel . In contrast, Makapuno coconut in this study exhibited less weight loss probably due to the viscosity of the endosperm, which restricted water loss through evaporation . Consequently,the color, SS and TA of Makapuno meat did not significantly change after 3 days of 30 ◦C storage. One of the major problems with coconut storage is the increasing rancidity of the endosperm that results from lipid oxidation i.e. the oxidative deterioration of lipids. This leads to an undesirable taste and smell during storage. Malondialdehyde is used as an indicator of lipid peroxidation , and generally, higher MDA levels correlate with higher rancidity . Although insignificant , the MDA of the meat increased 2-fold after 3 days at 30 ◦C storage. Compared to other coconuts, lipid oxidation is less problematic for Makapuno during storage,vertical farming technology probably due to the lower crude fat relative to non-Makapuno types . Another major problem of harvested coconut is decay. Deterioration of Makapuno fruit was evident as mold infestation on the husk surface, which also penetrated the fruit ‘eye’ after they were transferred to 30 ◦C for 3 days . The most prevalent fungal molds found on Makapuno husks were Aspergillus spp. and Penicillium spp. but Fusarium spp. and Curvulria spp. were also detected . Treating fruits with 3–5% sodium metabisulfite or linear low-density polyethylene—file wrap could not prevent surface mold or extend Makapuno coconut storage life when stored at 30 or 5 ◦C .As expected, fruit storage-life increased with decreasing temperature. At 5 ◦C the rate of respiration and ethylene production was reduced 3–6 fold and the storage life was increased to 42 days when stored at 5 ◦C rather than 3 days at 30 ◦C. Moreover, following transfer from 5 to 30 ◦C, respiration rates were similar to fruit kept continuously at 30 ◦C and ethylene production did not change , indicating that there was little or no chilling injury using these temperatures and storage times . During the 6-week storage period, fruit weight loss was significant but endosperm color, SS, TA and decay incidence were similar to those that were stored at 30 ◦C for 3 days. This may indicate that most of weight loss caused by loss of moisture from husk but not from the endosperm. Makapuno fruit developed symptoms consistent with post harvest chilling injury when stored at 2 ◦C for 4 weeks. Cold-stored fruits transferred to 30 ◦C for an additional 3 days exhibited signs of deterioration: the meat developed a woolly texture, and a rancid smell and taste coincided with higher MDA and decay scores. Thus, 2 ◦C was more unsuitable for Makapuno coconut storage than 5 ◦C.Generally, enclosing fruit in films, bags or coatings reduces water loss, prevents the spread of disease among batches of stored fruit and establishes an atmospheric composition that slows down deterioration . It was previously reported that high-OTR bags can enhance the shelf life of mature coconuts . To determine the effect of high-OTR on Makapuno coconuts quality,fruits were stored individually in high OTR bags and kept at 5 ◦C and compared to unbagged fruits held at 5 ◦C.

Coconuts in high-OTR bags had a high O2 transmission rate which allowed O2 to escape from the bag resulting in low O2 accumulation inside. Ethylene also accumulated, but the concentration was lower than 0.15 ppm. While the unbagged Makapuno coconut could be stored only for 6 weeks at 5 ◦C, Makapuno coconut kept in high-OTR bag and stored at 5 ◦C lasted for 10 weeks without any sign of deterioration. In addition, high OTR bag and 5 ◦C storage minimized evaporation very effectively as there was almost no weight loss after 10 weeks and there was no change even after transfer to 30 ◦C for 3 additional days . This reduction in weight loss is likely due to the high relative humidity maintained inside the bag. The combination of high-OTR bag and 5 ◦C effectively suppressed the growth of microbes probably via protecting the coconut from direct contact with fungi and preventing moisture condensation on husk surface. The CO2 and O2 concentration were not high or low enough to kill the fungi therefore it is unlikely that the modified atmosphere would affect fungi pathogen metabolism. The MA provided by the high-OTR bag also maintained SS, TA and MDA levels even after transfer to 30 ◦C. After 10 weeks storage in high OTR bags, fruit quality was maintained and coincided with a reduction in water loss. Thus it is hypothesized that the reduction in water loss might be the most important factor prolonging Makapuno storage life when stored in high OTR bags. However, conclusive proof of this hypothesis requires further experiment.What was once limited to the realm of science fiction and theoretical astrophysics models is now within an operational vision of exploring the “final frontier,” otherwise known as outer space. With the advent of cost-effective launch technologies and the gradual deregulation of space launches and flights, the global economic activity in the space industry has begun to surge. While satellite services likely comprise most viable and profitable venture in space, the adoption of novel space-based goods and services, from space tourism to organ bio-printing, show tremendous potential to disrupt even incumbent industries on Earth. The global space industry has increased in value from $162 billion in 2005 to $469 billion in 2021. While government spending increased 19% to add $107 billion to the space industry, much of the value growth can be attributed to the private sector: commercial enterprises provided an estimated $224 billion in goods and services and $138 billion from constructing infrastructure and support . The most recent space industry reports by Citi and Morgan Stanley project a $1 trillion valuation and $100 billion in annual revenues by 2040 . Space-related research and development has expanded dramatically based on the 22% annual increase for the past five years attributable to the private sector, in contrast to the 10% increase for U.S. governmental expenditures in nominal dollars . While NASA and public sector expenditures have stagnated $12 billion2 in the past few decades, “NewSpace” companies,3 or new companies emerging in the private space industry, have invested an estimated $5-6 billion in 2020, up from less than $1 billion in 2010 .

Spot s presented homology with the At4g27270 protein whose molecular function is to interact selectively with FMN, and also presents oxidoreductase activity. From the 6 spots not detected in root tip extracts from Fe-deficient plants as compared to the controls , 3 were identified by MALDI-MS . Proteins matched were oxalate oxidase , peroxidase and caffeoyl CoA Ometyltransferase .Changes induced by Fe-deficiency and Fe-resupply in the root tip metabolome were evaluated by non-biased gas chromatography mass spectrometry metabolite profiling. A total of 326 metabolites were present in at least 80% of the samples of at least one treatment, and 77 of them were identified. Partial least square analysis shows a good separation between +Fe and -Fe root tips . Iron-deficient samples were closer to the 24 h and 72 h YZ samples than to the 72 h WZ ones. On the other hand, the 72 h WZ samples were closer to the +Fe samples than to the -Fe ones.Iron deficiency and/or resupply caused significant changes in the levels of 62 out of the 77 identified metabolites. Metabolite level data were normalized to the mean response of the +Fe treatment; response ratios, defined as the level in a given treatment divided by the level in the +Fe control, are indicated in Table 2.Large increases were found for some organic acids , some sugars , nicotianamine and 2-aminoadipic acid. The response ratio of oxalic acid decreased markedly in -Fe conditions, whereas those of other aminoacids, N compounds, lipid metabolites and others did not show large changes when compared to the Fe-sufficient controls.

Twenty-four hours after Fe-resupply, there was a dramatic coordinated increase in the root tip response ratios of galactinol, raffinose, lactobionic acid, cellobiose and nicotianamine when compared to those found in Fe-deficient roots,vertical aeroponic tower garden whereas the response ratios of sucrose, myoinositol, citrate and malate decreased. Seventy-two hours after Fe resupply, the response ratios of galactinol, raffinose, cellobiose, nicotianamine and many other compounds had decreased in the YZ areas, whereas in the WZ the response ratios were very low. The response ratio of many of the lipids increased moderately in all Fe resupplied samples. Metabolites in the coenzyme, glycolysis, oxidative stress, pentose phosphate pathway and signalling categories did not show large response ratio changes with Fe resupply.The changes induced by Fe deficiency in the root tip proteome and metabolome from sugar beet plants grown in hydroponics have been studied. More than 140 proteins and 300 metabolites were resolved in sugar beet root tip extracts. Iron deficiency resulted in significant and higher than 2-fold changes in the relative amounts of 61 polypeptides, and 22 of them were identified. Out of 77 identified metabolites, 26 changed significantly with Fe deficiency. In general, our results are in agreement with previous transcriptomic, proteomic and enzymatic studies on Fe-deficient roots. Our data confirm the increases previously found in proteins and metabolites related to carbohydrate metabolism and TCA cycle pathways. Two major changes induced by Fe deficiency in roots are described in this study for the first time: the increase in DMRL synthase protein concentration and gene expression, and the increase in RFO sugars. The largest change found in the proteome map of root tip extracts from sugar beet plants grown in Fe deficiency conditions corresponded to DMRL synthase, which was detected de novo in Fe-deficient root tips, and is the protein with the highest concentration in these gels . This enzyme catalyses the fourth step of Rbfl biosynthesis, and Rbfl is the precursor of Rbfl sulphates, FMN and FAD, the last one being a cofactor for the root plasma membrane Fe reductase.

The expression of BvDMRL decreased drastically 24 h after the addition of Fe to Fe-deficient plants, whereas DMRL synthase protein abundance and Rbfl and Rbfl sulphate concentrations did not change significantly with Fe-resupply in the YZ of root tips , suggesting that the turnover of this protein is slow. Accumulation in Fe-deficient roots of flavin compounds, including Rbfl and Rbfl 3′ – and 5′-sulphate is a characteristic response of sugar beet and other plant species. The exact role of flavins in Fe deficiency is unknown, and it has been hypothesized, based on the similar location of flavin accumulation and Fe reduction and on the fact that the Fe reductase is a flavin-containing protein, that free flavin accumulation may be an integral part of the Fe-reducing system in roots from Strategy I plants. On the other hand, these compounds are secreted to the growth media at low pH and, assuming high concentrations at the secretion site, they could mediate extracellular electron transfer between soil Fe deposits and root Fe reductase as it has been described for flavin phosphates secreted by some bacteria. Moreover, excreted flavins could also act as a plant-generated signal that could influence rhizosphere microbial populations, indirectly affecting Fe availability. A major change in carbohydrate metabolism was the large increase in RFO compounds that occurs in roots with Fe deficiency. This increase was higher than that found for sucrose . The total concentrations of raffinose and galactinol were also determined by HPLC-MS, and concentrations of both compounds in the 35-80 nmol g FW-1 range were found in Fe-deficient and Fe-resupplied root tips , whereas concentrations in the +Fe treatment were one order of magnitude lower. The sum of the raffinose and galactinol concentrations in the -Fe, 24h, 72hWZ, 72hYZ and +Fe tissues was 13.9, 7.4, 2.2, 5.1 and 0.6% of the total sucrose, respectively, supporting the relevance of the RFOs changes with Fe status. RFOs have diverse roles in plants, including transport and storage of C and acting as compatible solutes for protection in abiotic stresses .

Other explanationfor the large increase in the relative amounts of RFOs could be the ability to function as antioxidants; galactinol and raffinose have hydroxyl radical scavenging activities similar to other soluble antioxidants such as glutathione and ascorbic acid. Since ROS damage and ROS detoxification strategies have been observed in Fe-deficient roots, the increase in RFO concentration could help to alleviate ROS damage produced under Fe deficiency. Moderate increases in sugars commonly found in cell walls such as cellobiose, xylonic acid and arabinose, which may indicate cell wall modifications, were measured in sugar beet Fe-deficient root tips. Changes in cell wall metabolism have been also described in Fe-deficient tomato roots. On the other hand, it has been described that cell wall damage generates oligosaccharides that can act as signalling molecules in stresses such as wounding. The increase in RFOs could also act as a long distance Fe-deficiency signal via phloem sap transport. This is the first description of RFOs accumulation in plants under Fe deficiency, and the physiological implications of this increase deserve further consideration. Most of the proteins found to be up-accumulated in sugar beet root tips by Fe deficiency were identified as carbohydrate catabolism enzymes, including 5 of the 10 glycolytic pathway enzymes ,vertical gardening in greenhouse one of the citric acid cycle and fructokinase. Increases in the activities and concentrations of several glycolytic enzymes in root extracts with Fe deficiency have been previously found, including fructose 1,6-bisphosphate aldolase, enolase, triosephosphate isomerase and GADPH. Also, increases in the activities and concentrations of several enzymes of the citric acid cycle with Fe deficiency have been previously reported in root extracts, including MDH. Results are also in agreement with micro-array gene analysis in Fe-deficient A. thaliana roots. Increases in the amount of PEPC have been found at the protein level, but this enzyme, with a molecular mass of 110 kDa, was not in the range used in our 2-D gels. Up-regulation of carbohydrate catabolism in roots of plants grown in Fe deficient conditions is probably a result of an increased demand of energy and reducing power in roots needed to sustain the increased activity of H+-ATPase and Fe reductase. Also, two spots corresponding to different subunits of F1 ATP synthase increased in 2-D gels from Fe deficient root tips, further supporting the higher energy requirement in these roots. Moreover, our results show an increase in the amount of formate dehydrogenase, an enzyme related to the anaerobic respiration, in Fe-deficient roots, confirming the results of enzyme and transcriptional analysis. Anaerobic respiration is an alternative pathway for energy production when oxidative phosphorylation is impaired. Metabolite studies revealed large increases in organic acids, including a 20-fold citric acid increase. These increases in TCA cycle organic acids with Fe deficiency are coupled with increases in glycolysis and root C fixation by PEPC, and provide an anaplerotic, non-autotrophic C source for leaves which have otherwise reduced photosynthetic rates.

Malate and citrate could also be pumped from the cytosol to the mitochondria via a di-tricarboxylate carrier where they would allow a higher turnover of reducing equivalents. A significant decrease in oxalic acid concentration was observed in Fe deficient root tips, and similar decreases have been reported in Fe-deficient tomato roots. The implications of oxalate concentration decreases with Fe deficiency are still not known, since the role of oxalic acid in plants is quite different from that of the other organic acids, and for a long time it has been considered as a toxin or a metabolic end product . Regarding N and amino-acid compounds, a large increase was measured for nicotianamine, which has been described to play a role in cytosolic Fe availability. A comprehensive representation of the metabolomic and proteomic changes taking place in root tips under Fe deficiency and resupply is shown in Figure 4. Red and yellow symbols indicate major and moderate increases in metabolites and proteins compared to the Fe-sufficient controls. Blue and green symbols indicate major and moderate decreases in metabolites and proteins compared to the controls. Besides the major increases in RFOs and DMRL, Fe deficiency induced significant changes in root tip metabolism, mainly associated to increases in carbohydrate catabolism, glycolysis and TCA cycle and to a lesser extent in aminoacid and nitrogen metabolism . Similar changes were observed in the 24 and 72h YZ Fere supplied roots, whereas the WZ of 72 h Fe-resupplied plants did not show major changes when compared to +Fe plants . On the other hand, the relative amount of lipid metabolism compounds did not change markedly in Fe-deficient roots, whereas Fe resupply caused a moderate increase in this type of metabolites .Sugar beet was grown as described elsewhere. “Monohil” was always used, with the exception of raffinose and galactinol analysis, which was carried out with “Orbis”. After seed germination in vermiculite and 2 weeks in half-strength Hoagland’s nutrient solution with 45 μM Fe-EDTA, plants were transferred into 20 L plastic buckets containing half strength Hoagland’s nutrient solution with either 0 or 45 μM Fe-EDTA. The pH of the Fe-free nutrient solution was buffered at approximately 7.7 by adding 1 mM NaOH and 1 g L-1 of CaCO3. In the Fe resupply experiments, plants grown for 10 d in the absence of Fe were transferred to 20 L plastic buckets containing half strength Hoagland’s nutrient solution, pH 5.5, with 45 μM Fe-EDTA. The root sub-apical region from Fe-sufficient plants , Fe-deficient plants , Fe-deficient plants resupplied with Fe for 24 h and Fe-deficient plants resupplied with Fe for 72 h was collected with a razor blade and immediately frozen in liquid N2. The specific regions of root sampled were: in the case of +Fe, -Fe and 24 h plants, the first 10 mm from the root apex ; in the case of 72 h Fe resupplied roots two zones were sampled separately, the first 5 mm from the root apex, where a new white zone had developed , and the next 5 mm, comprising the still swollen and yellow root zone . Samples were taken at approximately 4 h after light onset in the growth chamber.Protein extracts were obtained as described elsewhere and protein concentration was measured with RC DC Protein Assay . A first dimension isoelectric focusing separation was carried out on ReadyStrip IPG Strips , using a linear pI gradient 5-8. Strips were loaded in a PROTEAN IEF Cell and focused at 20°C, for a total of 14000 V.h. For the second dimension polyacrylamide gel electrophoresis , IPG strips were placed onto 12% SDS-PAGE gels to separate proteins between 10 and 100 kDa. Proteins were stained with Coomassie-Blue R- 250 and results analyzed with the PDQuest 8.0 software.

During this rule making, the US EPA will also reexamine the NSR requirements applicable to existing non attainment areas, in order to address issues of fairness among existing and new non attainment areas. The transitional classification will be available for any area attaining the one-hour standard but not attaining the eight-hour standard at the time the US EPA promulgates the new rules.To encourage early planning and attainment for the eight-hour standard, the US EPA will make the transitional classification available to areas not attaining the eight-hour standard that will need additional local measures beyond the regional transport strategy, as well as to areas that are not affected by the regional transport strategy, provided they meet certain criteria. To receive the transitional classification, these areas must submit an attainment SIP prior to the designation and classification process in the year 2000. The SIP must demonstrate attainment of the eight-hour standard and provide for the implementation of the necessary emission reductions on the same time schedule as the regional transport reductions.By submitting these attainment plans earlier than would have otherwise been required, these areas would be eligible for the transitional classification and would achieve cleaner air much sooner than otherwise required.The majority of areas not attaining the one-hour standard have made substantial progress in evaluating their air quality problems and developing plans to reduce emissions of ozone-causing pollutants. These areas will be eligible for the transitional classification provided that they attain the one-hour standard by the year 2000, and comply with the appropriate provisions of section above depending upon which conditions they meet.For areas not eligible for transitional classification, their work on planning and control programs to meet the one-hour standard by their current attainment date should advance toward meeting the eight-hour standard.

While the additional local reductions that they will need to achieve the eight-hour standard must occur prior to their eight-hour attainment date , for virtually all areas the additional reductions needed to achieve the eight-hour standard can occur after the one-hour attainment date. This approach allows them to make continued progress toward attaining the eight-hour standard throughout the entire period,low round pots without requiring new additional local controls for attaining the eight hour standard until the one-hour standard is attained. These areas, however, will need to submit an implementation plan within three years of designation as non attainment for the new standard for achieving the eight-hour standard. Such a plan can rely in large part on measures needed to attain the one-hour standard. For virtually all of these areas, no additional local control measures beyond those needed to meet the requirements of Subpart 2, Part D of Title I, would be required to be implemented prior to their applicable attainment date for the one-hour standard. Non attainment areas that do not attain the one-hour standard by their attainment date would continue to make progress in accordance with the requirements of Subpart 2, and the control measures needed to meet progress requirements under Subpart 2 should generally be sufficient for meeting the control measure and progress requirements of Subpart 1, as well .After the 1973 OPEC oil embargo, Congress and the public became concerned about the increasing dependence of the U.S. on foreign oil. Since the price of petroleum products was controlled well below market levels, many individuals thought that conservation should be encouraged through the use of non-price mechanisms. In 1975, Congress enacted the Energy Policy and Conservation Act, which placed a particular emphasis on auto fuel economy since the greatest share of petroleum consumption was used by the automobile sector . “This legislation required that the corporate average fuel economy for new cars be raised gradually from 14.2 miles per gallon in model year 1974 to 27.5 miles per gallon by model year 1985” . From the early 1970s to the mid-80s, the average fuel economy of new domestic automobiles increased more than 100 percent .

Gains in CAFE were achieved by: 1) reducing the weight of automobiles, 2) improving engine and drive train efficiency, 3) reducing tire rolling resistance, and 4) improving the aerodynamics of design. Nevertheless, overall gasoline consumption by light-duty vehicles did not decline sharply and is now higher than ever before. There are several reasons why CAFE has not been a more effective instrument for reducing gasoline consumption. The four major factors influencing fuel consumption include: 1) more vehicles in the fleet, 2) more miles driven per vehicle. From 1985 to 1994, there was a 7.6 percentage point increase in the number of trucks and a 0.2 percentage point decrease in the number of passenger cars. The fuel economy of trucks was notably lower than passenger cars , p4-S, Table 4.4). This growth appears to have been driven mainly by demographics, vehicle prices, and consumer incomes. The second factor, average vehicle miles driven, has also risen, particularly for trucks. In addition, the shift in consumer preferences toward light trucks has had an important impact on gasoline consumption. The total number of vehicles miles traveled has been influenced by low gasoline prices. Not surprisingly, the price of gasoline also appears to affect the average miles per gallon through its influence on consumer preferences for more fuel-efficient vehicles and on the decisions of two car families to drive more fuel-efficient automobiles. Nevertheless, it is important to note that CAFE only directly improves miles per gallon of new vehicles. The overall impacts on the fuel economy of the entire fleet occurs very slowly, as older vehicles are retired. At present, the average fuel economy for the entire fleet is approximately 24 miles per gallon, which is about the same as in 1980. In an evaluation of the effects of CAFE on the nation’s fuel consumption, it is important to recognize two counterproductive effects of these standards. First, CAFE encourages increased driving because it lowers the cost of travel. Second, CAFE can encourage the retention of older, low-mileage vehicles because it adds to the costs of manufacturing new vehicles. Hence, these factors have the potential to inadvertently increase pollution because emissions increase proportionately with miles driven and more than proportionately with the age of the vehicles.

The National Environmental Policy Act is one of the most significant pieces of environmental legislation in U.S. history. Passed by Congress in 1969 and signed into law in 1970, NEPA requires federal agencies to consider the environmental consequences of their actions before executing them. In preparing and passing NEPA, Congress recognized “the profound impact of man’s activity on the interrelations of all components of the natural environment, particularly the profound influences of population growth, high-density urbanization,plastic pots 30 liters industrial expansion, resource exploitation, and new and expanding technological advances”. The language of NEPA recognizes the importance of several things: 1) preserving the environment for future generations; 2) maintaining the safety, health, productivity, and well being of the American people; 3) using the products and materials of the natural environment of the country without diminishing them to the point of destruction; and 4) maintaining a balance between the growing population of the U.S. and the country’s natural resources . NEPA requires all agencies of the federal government to assess the possible adverse environmental impacts of proposed actions and legislation. NEPA applies to actions where FHWA, FTA, or agencies delegated the authority for such decisions have control over project approval. Consequently, NEPA applies to many of the projects to which conformity applies . If a federally proposed project has the potential to yield a significant environmental impact, compliance with the NEPA mandates is accomplished through the preparation of an environmental impact Statement . Under NEPA, all EISs must include: 1) a detailed Statement on the environmental impact of the proposed action; 2) a description of any adverse environmental effects that cannot be avoided should the proposal be implemented; 3) a discussion of alternatives to the proposed action; 4) a treatment of the relationship between local short-term uses of the environment and long-term productivity of the area; and 5) a discussion of any irreversible commitments of resources to be involved in a proposed action ) . In Title II of NEPA, Congress established the Council on Environmental Quality as the administering agency of the Act. NEPA required that CEQ develop a set of regulations for implementing the NEPA mandates. These Regulations are contained at 40 CFR Parts 1500 to 1508. Under the CEQ regulations, federal agencies are required to adopt procedures to ensure that applicable project-related decisions are made in accordance with the policies and purposes of the Act. The US DOT’s FHWA and FTA NEPA regulations are contained at 23 CFR Part 771 .In response to many air pollution problems, California adopted the California Clean Air Act in 1988 . California enacted the legislation in recognition of the fact that most urban areas of the State had not attained federal ambient air quality standards by the federal deadline of August 31, 1988. The CCAA directed the development and implementation of California’s own program to attain the ambient air quality standards at the earliest practicable date. Although a significant portion of the CCAA focuses on attainment of ambient standards in air pollution control districts, the statute directs the CARB to reduce emissions of motor vehicles .

The CCAA added a new section to the Health and Safety Code, Section 43000.5, which States: “the State board should take immediate action to implement both short- and long-range programs of across-the-board reductions in vehicular emissions which can be relied upon by the districts in the preparation of their attainment plans or plan revisions”. The CCAA also amended Section 43013, which added a subsection authorizing standards for specific types of motor vehicles and related equipment. “The State Board may adopt and implement motor vehicle emissions standards, in-use performance standards, and motor vehicle fuel specifications for the control of air contaminants and sources of air pollution which the State board has found to be necessary, cost-effective, and technologically feasible to carry out the purposes of this division” . Finally, the CCAA enacted Section 43018. Section 43018 States that the State Board shall try to achieve the maximum degree of emission reduction in mobile and vehicle emissions to meet the State standards. Section 43018 States that the Board shall take whatever actions are necessary, no later than January 1, 1992, to attain a reduction in the emissions of HC and NOx by December 31, 2000. The Board must also achieve maximum feasible reductions in particulates, CO, and toxic air contaminants. Section 43018 establishes that the Board must adopt standards that result in cost-effective control measures on all motor vehicles and motor vehicle fuels. Finally, Section 43018 “…establishes a specific timetable for the Board to conduct workshops and rule making hearings for specific regulations regarding motor vehicles and motor vehicle fuels.”In summary, the California legislators enacted the CCAA as a result of the State’s recognition of its air pollution problems and its inability to meet the federal ambient air quality standards in many urban areas by August 1988. The Act is ambitious and far-reaching in its goals and objectives. For the first time, a vehicle and its fuel would be treated as a system that would have to meet exhaust emission standards. This integrated approach, based on performance of the vehicle/fuel system, provides flexibility and encourages the vehicle and fuel industries to work together to develop the least polluting and most cost-effective vehicle and fuel technologies. Hence, California was the first State to adopt the most stringent vehicle emissions legislation. It is important to note that California legislators had established these goals and standards prior to enactment of the federal CAA 1990. Although the California regulations were already in place, the CAA of 1990 require the introduction of clean-fuel cars in California beginning in 1996. The CAA of 1990 also provides a voluntary “opt-in” provision that allows other States to adopt the California standards . California is the only State that can set higher emission standards than the federal government; after California has established higher standards other States can then adopt them.

Non-sequential selective dissolution in Na-pyrophosphate and ammonium-oxalate was used to characterize Fe, Al and Si in various pedogenic pools. Total C and N concentrations were determined on ground samples by dry combustion using a Costech C/N analyzer . Soil microbial biomass C and N were measured using chloroform fumigation and direct extraction with 0.5 M K2SO4 . Briefly, 10 g oven-dry equivalent samples were fumigated for 48 h in the dark, and then C and N were extracted with 0.5 M K2SO4. Similar extraction was applied for non-fumigated samples. Total dissolved organic C and total extractable N were measured using a C/N analyzer . The non-fumigated control values were subtracted from fumigated values as an estimate of microbial C and N. A Kec/Ken factor of 0.35 was applied for both C and N . Carbon mineralization was measured in the topsoil and subsoil by incubating duplicate soil samples in the dark under laboratory conditions over a 119-day period. Soil moisture was adjusted to ∼ 80% of field capacity and pre-incubated for one week prior to starting the long-term incubation. Soils were incubated in sealed Mason jars fitted with septa. Carbon dioxide in the head space of each soil sample and blanks with no soil was measured each week using an Infrared Gas Analyzer. The CO2 emission was normalized to initial total C content of each soil and expressed as CO2-C mg kg−1 soil C. In addition, net N mineralization was measured on these same samples at the end of the 119-day incubation by determining concentrations of mineral N in 1 M KCl extracts at time zero and at 119 days. Quantification of NO3 – used the vanadium chloride method and NH4 + the Berthelot reaction with a salicylate analog of indophenol blue.

A correlation analysis was performed to assess soil properties most strongly affected by land-use changes,microgreen fodder system using IBM SPSS Statistics 22. 2013.All soils were well drained with an A horizon overlying Bw horizons that extended to the depth of investigation . Soil particle-size distribution was similar among the four sites with the majority of the horizons having a loam texture . Some distinct changes in particle-size distribution within various pedons are attributable to more recent tephra deposition that resulted in burial of the former soil profile. Bulk density in subsoil horizons was very low , characteristic of soils formed in volcanic ash . Db was also low in the A horizon of the pine forest , but was higher under agricultural management due to traffic compaction resulting in a reduced pore volume. The agricultural soils displayed a distinct increase in Db and a reduction in total porosity in the topsoil horizons compared to the pine forest soil. Given the low bulk densities, total porosity was correspondingly high, ranging between 60 and 77%, with values decreasing in surface horizons with agricultural management. Plant-available soil water was generally in a narrow range with the exception of the surface horizons of the pine forest soil . The water retention capacity varied from 37 to 53% in topsoil horizons and from 45 to 51% in subsoil horizons with the lowest values in the pine forest.Soil pH-H2O increased from very strongly acid in the pine forest and tea plantation to moderately acid in the horticultural crops with fallow and intensive cultivation . Regardless of land use, all soils in this study had low CEC characteristic of acidic Andisols dominated by allophanic materials.The pHKCl-pHH2O values ranging between −0.1 and −0.5 were indicative of a soil colloidal fraction dominated by variable charge materials . Especially notable is the very low base saturation and concentrations of exchangeable Ca and Mg for the PF and TP soils . Exchangeable base cations are a common limiting factor for horticultural production in the studied Andisols since these nutrient cations are extremely low under pine forest.

While the horticultural management practice of applying horse manure and lime did not appreciably increase the measured CEC, it was remarkably effective in increasing exchangeable base cations . For example, exchangeable Ca, Mg and K increased from 1.5, 0.3 and 0.2 cmolc kg−1 in the pine forest to 26.3, 3.5 and 1.0 cmolc kg−1 in the intensive horticultural crops, respectively . The high base saturation of over 100% under horticultural land uses compared to < 23% for the pine forest and tea plantation .Organic C concentration in A horizons was highest in PF and 1.0 to 2.0% lower under agricultural management . In contrast, organic C was lower in the PF subsoil while the agricultural sites had elevated organic C concentrations in several subsoil horizons. Organic C stocks in the upper 100 cm of the soil profile were calculated by summing the organic carbon stocks in each individual horizon were present). Organic carbon stocks followed : TP ≈ IH > FH > PF . The agricultural soils contained more organic carbon than the pine forest soil. While horse manure was added to the IH soil for the past 7 years, the TP and FH soils received no organic matter amendments and still had similar pedon organic matter stocks. As a direct comparison, the IH soil receiving horse manure contained only slightly more organic C than the FH soil located 4 m away that received no horse manure and was fallowed over the past 7 years. Dissolved organic carbon concentrations were appreciably higher in the PF topsoil and throughout subsoil horizons of the TP profile . The horticultural soils tended to have lower overall DOC concentrations than PF and TP land uses. Total N concentrations followed a similar distribution to organic C concentrations among sites with total N stocks in the upper one meter of soil following : IH > FH ≈ TP > PF . The C:N ratio was lowest in the upper 50 cm of the IH and FH soil profiles , while values for PF, TP and lower soil horizons at all sites were generally in the range 16 to 19.

The highest concentrations of inorganic N were found in the IH pedon and were dominated by NO3 – . In contrast to the IH soil dominated by NO3 – , inorganic N concentrations were dominated by NH4 + in the TP, FH and PF soils with the highest value in the TP soil and lowest under FH land use. High P fixation , characteristic of Andisols, was exhibited for all land-use types. Under forest vegetation , the soil P retention was consistent at 97% throughout the entire pedon . Change of land use to TP and FH did not appreciably affect P fixation. However,barley fodder system the IH land use receiving application of horse manure for the past 7 years showed appreciably lower P fixation in the upper 40 cm. Reflecting the high P fixation, available P content was below the detection limit for all horizons of all land-use types, except for the upper horizons of the IH land use .Extractable SO4-S content was considerably higher in the PF and TP pedons as compared to the horticultural pedons . Change of land use from pine forest to agriculture decreased extractable S content. The exception is the TP pedon that contains high S due to application of kieserite as an integral part of tea plantation fertilizer management. Extractable micronutrient concentrations showed the following general order of abundance: Fe ≫ Mn > Cu > Zn . In terms of land-use, micronutrient levels followed the general pattern of IH > FH > TP > PF.There were several significant correlations among soil properties . Oxalate-extractable Sio showed a positive correlation with the clay fraction, while Feo had a strong negative correlation with pH and exchangeable Ca and Mg. In contrast, Alo showed no significant correlations with other soil properties. For organo-metal complexes , Alp had highly negative and positive correlations with the clay fraction and organic C, respectively. However, Fep showed no significant correlations with other soil properties. Soil pH showed a highly negative correlation with P retention and Feo, along with a positive correlation with exchangeable cations , total N and Db. Soil bulk density showed a positive correlation with exchangeable cations and negative correlation with P retention. P retention had a negative correlation with exchangeable cations .Andisols are characterized by low Db and high porosity due to the abundance of amorphous and poorly crystalline materials and organic matter that contribute to highly stable and very well structured soils under natural conditions. However, the low natural Db may change due to anthropogenic activities. The evidence was revealed by soil tillage under intensive horticultural crops contributing to increased Db from compaction by potential destruction of soil aggregates due to physical mixing/abrasion by tillage operations. Tillage was reported to destroy macropore pathways of Andisols in Mexico resulting in a lower infiltration and permeability of topsoil horizons .Chemically, the exchangeable cations have positive significant correlation with Db, indicating the increase in soil exchangeable cations gave rise to the increased soil bulk density . This is probably due to the role of Ca and Mg ions derived from lime and manure in binding soil particles, resulting in the change of soil friable structure under forest to more compact aggregate formation under intensive horticultural cultivation.

The water retention capacity varied from 37 to 53% in topsoil horizons and from 45 to 51% in subsoil horizons with the lowest values in the pine forest . These data indicate that the number of soil pores storing plant-available water is lower in the forest Andisols than those converted for agriculture. In other words, the water retention capacity has increased about 50% following conversion from pine forest to agriculture. This implies that the compaction associated with tillage is responsible for increasing the water retention capacity through conversion of macropores to meso/micropores. The water retention capacity in this study was higher than for cultivated Mexican Andisols reported by Prado et al. . The high water retention in Andisols is caused primarily by their large volume of meso/micropores . Formation of these meso/micropores is greatly enhanced by poorly crystalline materials and soil organic matter . Buytaert et al. studied toposequece of Andisols in south Ecuador and reported the large water storage capacity as revealed by water content ranges from 2.64 g g−1 at saturation, down to 1.24 g g−1 at wilting point. The long-term cultivation of agricultural soils in this study has not caused appreciable degradation to the overall Db, porosity or water retention characteristics of these Andisols. While macroporosity was decreased by tillage, the macropore content of topsoil horizons remained > 15% providing adequate infiltration and soil aeration. The loss of macropores is compensated for by the increase in meso/micropores that contribute to increased plant-available water holding capacity. In spite of the increase of bulk density and loss of macropore capacity, field observations confirmed that the agricultural soils in this study retained their high infiltration capacity with no evidence of surface runoff. In Italy, well developed Andisols on flow-like landslides over 70 years experienced low run off and minimal soil erosion owing to a good infiltration in spite of the high slope steepness and the anthropic pressure associated with land management .The pine forest soil was very strongly acidic owing to the strong leaching regime associated with the isothermic/perudic climatic regime. Applications of lime and more recently horse manure to the IH soil were effective in raising the pH of the horticultural soils . In spite of the low soil pH values in the tea plantation, the potential for Al3+ toxicity was not evident as ascribed to the low exchangeable Al3+ concentrations . Threshold values for Al toxicity are generally considered about 2 cmolc kg−1 for common agricultural crops and 1 cmolc kg−1 for Al-sensitive crops . Andisols dominated by allophanic materials generally contain low KCl-extractable Al concentrations; however, these values may be underestimated due to “induced hydrolysis” of displaced Al and subsequent adsorption of polymeric Al to allophanic materials . The elevated pH associated with the horticultural soils reduced the exchangeable Al3+ concentrations to non-detectable levels , further reducing the potential for Al3+ toxicity. A notable findings in this study was the increase in soil pH and base saturation following land use changes as revealed by the strongly positive correlation between soil pH and exchangeable cations .

In the absence of photo assimilation, the starch stored in the source is degraded to replenish cellular sugars in order to avoid carbon starvation. Therefore, carbon assimilation and utilization is carefully balanced for optimal plant development. Adverse environmental conditions can disrupt the normal starch and sugars levels with repercussions for the ability of the plant to sustain growth. Drought is associated with reduced starch or sugar levels in source tissues. Salinity stress can induce higher starch accumulation in the source or sink of some species, but trigger starch reduction in others. Similarly, chilling stress is associated with accelerated source-starch accumulation or degradation. These observed increases in starch or sugars may be adaptive responses for stress-survival, or may be ‘injury’ responses resulting from the under-utilization of carbon because of growth cessation, regardless, documenting these changes is necessary for a deeper understanding of plant stress response. Feeding plants with 14CO2 is useful for tracking carbon movement, and can inform on changes in carbon allocation due to stress. Available data suggests that stress generally accelerates allocation to the sinks as an adaptive response. Salinity increased flux from source to developing fruits in tomato and to the roots in transgenic rice seedlings. Water-stress elicited a similar distribution pattern in Arabidopsis, with higher 14C allocated to the roots, in beans, where 14C flux to the pods increased, and in rice, where it stimulated 14C mobilization from the stem and allocation to the grain. Additional 14C-allocation studies under varied stress conditions could help to clarify whether or not higher source-sink flux is a universal stress response.

The observed changes in local and distant carbon fluxes in plant tissues during stress result from multiple activities – epigenetic, transcriptional, post-transcriptional and post translational changes,dutch buckets occurring across different spatial and temporal scales, which must be integrated to deliver a cohesive response to stress. Te trehalose-6-phosphate/Sucrose non-Fermented Related Kinase 1 signaling cascade may function in this way. It is critical for plant survival under low carbon and energy conditions, in part through changes in starch metabolism. Te T6P/SnRK1 can also modulate source-sink interactions; therefore, key elements of this regulatory network could potentially be activated for a ‘rewiring’ of whole plant carbohydrate use under stress. Because of the many issues with respect to plant carbon use under stress that remain unresolved, our aim in this work was to investigate changes in carbon partitioning and allocation in response to short-term drought, salinity, and cold stresses. 14CO2-labeling of a single source leaf was used to map whole-plant and intra-tissue changes in carbon use, as it can provide partitioning and allocation data in the same system. Single-leaf labeling permits more accurate tracking of 14C-movement than can be obtained by exposing the entire rosette to the label.By comparing plants exposed to different stresses it may be possible to identify convergent and divergent adaptive responses associated with each unfavorable condition. Starch content was also assayed in the source leaf and the roots of the stressed plants and the data were compared to 14C-starch fluxes to identify how starch metabolism may be regulated to alter sugar distribution. Finally, the transcriptional activity of key genes in the T6P/ SnRK1 pathway was assessed to identify genes associated with changes in carbohydrate levels under abiotic stress. By integrating these data, we present one of the first comprehensive pictures of how Arabidopsis changes carbon flux under short-term environmental stress. This information could be combined with that generated from the wealth of -omics data to broaden our understanding of plant stress response.Our first aim was to investigate how plant source and sink tissues use carbon over the diurnal cycle under normal conditions. One hour before the middle of the day , a single mature, but still developing source leaf was fed with 14CO2 for 5 min. Te labeled source leaf, unlabeled sink leaves, and the roots were harvested separately at MD, at the end of the day , and at the end of the night . MD, ED and EN correspond to 6h, 12h and 24h after dawn. Te percentage of 14C distributed among the source and the sinks was determined.

Within each tissue, the incorporation of 14C into the main metabolites pools: sugars, amino acids, organic acids, starch, protein, and ‘remaining insoluble compounds’ , was established. First, we calculated the percentage of 14C distributed from the source to the sinks. During the day, ~60% of the 14C was retained in the source leaf, but by EN, the percentage of total 14C was evenly distributed among all tissues . Nighttime export of 14C from the source, and its subsequent allocation into the sinks, accounted for the re-distribution. Second, we examined the 14C partitioning between the source and sinks to create a full picture of how allocation and subsequent partitioning were altered. Partitioning in the roots was more dynamic than in the sink leaves, and this difference was amplifed most at ED . In the roots, there was increased incorporation of 14C into metabolites used for growth — i.e. sugars, amino acids, and RICs — and less into those used for storage —i.e. protein and starch — compared to the source. Te pattern of 14C-partitioning in source leaf vs. roots therefore reflected the prioritization of biological processes in each tissue type. Te other change of note occurred at EN, when both sinks incorporated less 14C into organic acids but more into starch compared to the source. This may indicate that the sinks had greater sufficiency with respect to carbon with a relatively reduced need for organic acids as sources of energy compared to the source. Finally, we examined changes in 14C-partitioning over the diurnal cycle . Data at ED and EN were compared to that generated at MD to fully assess how the day-night cycle affected carbon partitioning in different tissues. Te metabolic pools in the source leaf were variable, while those in the sinks were relatively stable. Relative to MD, there was less 14C in the sugar and starch fraction, but an almost 2-fold greater flux into organic acids at EN in the source. Organic acids may serve as the primary substrate for respiration after reductions in the sugar pool. In the roots, at EN, the 14C percentage in sugars decreased, but increased in starch. This indicates that the starch in the roots was accumulated constantly during the diurnal cycle, with more accretion during the night than the day. In contrast, in the sink leaves, the carbon flow into sugars and starch were stable at EN, but there was a 4-fold increase in the 14C partitioned into the RICs, suggestive of nighttime growth processes.How stress altered Arabidopsis carbon use over the diurnal cycle at the cellular and whole plant level was examined.

Arabidopsis seedlings were exposed to salinity stress using 100 and 200mM NaCl, to osmotic stress using 150 and 300mM mannitol, and to cold stress by exposing roots to 0 °C cold at the beginning of photoperiod. Afer 5hours of stress treatment,grow bucket a single mature source leaf was fed with 14CO2 for 5min. Sampling was done as previously described. Osmotic stress. Carbon allocation was negatively affected by osmotic stress, and the inhibition grew in severity as the stress progressed . By EN, mild and severe mannitol stress increased the percentage of 14C in the source, and decreased it in the roots . This could reffect reduced carbon export due to enhanced source activities, inhibited carbon export from the source, reduced sink strength, or a combination thereof under osmotic stress. Carbon partitioning within the source was also modulated to a greater extent than in the sinks . At MD, both mild and severe osmotic stress reduced the 14C-partitioned into starch but increased 14C-partitioning into organic acids in the source, presumably for respiratory use. Six hours later, only severe osmotic stress had this effect leading to greater 14C flux into osmoprotectants — sugars, organic acids, and amino acids — at the expense of the storage compounds . Te 14C-flux into these osmoprotectants also increased in both sinks at the expense of the RICs, with the latter decreasing drastically in the roots. Salinity stress. Te most obvious change was the percentage of 14C allocated from source leaf into roots, which decreased significantly by EN under both mild and severe NaCl stress . Te 14C-use in source leaf was more responsive to salinity compared to the sinks . Severe salinity stress decreased 14C-partitioning into starch but increased partitioning into sugars, amino acids, and organic acids during the day in the source. At MD, more 14C was partitioned into sugars in the sink leaves, but 6h later at ED the 14C in sugars was stable, with reduced flux into starch and proteins. This indicates that 12h after the stress treatment, carbon was diverted from storage and preferentially partitioned into sugars for osmoprotection. In the roots, less 14C was partitioned into the RICs at ED and EN compared to the control, which suggest a shift away from investing 14C into resources normally used for root growth under salinity. This may have led to increased 14C accumulation into sugars at the end of night because they were under-metabolized. Interestingly, proteins were the only metabolite affected by both mild and severe salinity stress in both source and sink leaves, while it was unchanged in the roots.Further, unlike sink leaves, the source had increased 14C label in protein at MD . Te changes in 14C partitioning and allocation in response to different levels of salinity stress are summarized as follows: the source leaf partitioned less 14C into storage compounds but more 14C into osmoprotectants in response to severe salinity stress; sink tissues showed a differential response to salinity stress: similar to the source leaf, the sink leaves showed reduced 14C in storage compounds, however, roots tissue had reduced 14C in structural compounds; and the amount of 14C imported into roots tissue was inhibited by salinity; this might be due to reduced sink activity, inhibited phloem transport, or a combination thereof. Cold stress. Te percentage of 14C in root tissues was significantly reduced by cold stress at the end of night, showing similarity to tissues under osmotic and salinity stress . Carbon allocation was not affected by low temperature during the day , but carbon partitioning was highly regulated in the source leaf , especially at the end of day. Te most notable difference was that the 14C-flux into starch and RICs decreased relative to the control plants. Te decrease in starch was high at MD but lessened during the diurnal cycle, while the opposite was true for the RICs, where inhibition intensified over the day. In the source, there were also higher fluxes into sugars, amino acids, and organic acids from MD to ED. Cold also triggered increased 14C into the protein pool at MD, and decreased it at ED. At EN, the 14C in RICs strongly decreased, with a corresponding strong increase in sugars. Cold stress therefore stimulated more 14C partitioning into sugars over the diurnal cycle in the source leaf. Te sinks were less affected by cold than the source. In sink leaves, there was increased carbon flow into sugars during the day and decreased carbon into starch at night, with no difference in RICs. In contrast, the roots had increased 14C in the sugar pool at night, and reduced partitioning into the RICs . This change of 14C partitioning suggests reprioritization of reserves with a greater flux towards sugars for osmoprotection at the expense of other pathways.Te 14CO2 labeling experiment showed that starch is the most dynamic metabolite pool that changed under all types of abiotic stresses used in this study. 14C-flux into starch was down-regulated by abiotic stress, and the regulation depended on the time of day and tissue type examined. Under control conditions, 14C-partitioning into starch was stable during the day but decreased at night in the source leaf . However, this pattern was disrupted under salinity and cold stress due to reduced carbon flow into starch. In contrast to the source leaf, 14C in starch in sink leaves did not change during the day even under stress. In roots, the percentage of 14C into starch normally increased by EN, and interestingly, this partitioning was maintained under osmotic stress, but not under salinity and cold stress.