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 .