Tag: greenhouse vertical farming

The first scenario consisted of applying the same amount of fertilizer spread across all irrigation pulses , except for the last irrigation pulse to enable flushing. The second scenario consisted of continuous irrigation of the same duration and irrigation amount as under pulsed treatments, with fertigation at all times , except for the same period of flushing at the end of irrigation. The fertigation scheme in PF1, PF2, PF3 and continuous scenarios was assumed to start from 17 August 2010. All fertigation simulations were run as for the irrigation experiment, that is for 29 days .The water content distribution in the soil reflects water availability to plants, and plays a crucial role in water movement through and out of the root zone. Volumetric water contents simulated by HYDRUS 2D/3D are compared in Fig. 5 with the measured values obtained using EnviroSCAN probes 15 cm away from the dripper. Simulated values matched measured values well, both spatially and temporally. However, deviations between simulated and measured values were observed at day 19 of simulation, particularly in the upper 50 cm of the soil profile; at later times this difference was not observed. Simulated and observed daily and cumulative drainage are compared in Figs. 6 and 7, respectively. It can be seen that simulated daily drainage remained slightly below observed values , except for the initial higher leaching on day 1. However,vertical hydroponic nft system the total drainage observed in the lysimeter was matched closely by the model.

The high peak on day represents the effect of high rainfall on that day, which also was very well predicted by the model. However, the cumulative drainage remained slightly over predicted during the initial 15 days, after which the simulated and observed values matched well. Model evaluation was performed using a number of model performance parameters calculated using measured and model generated soil water contents . The mean absolute error varied from 0.006 to 0.22 cm3 cm−3 and the root mean square error ranged between 0.007 and 0.028 cm3 cm−3, which indicated small deviations between measured and simulated values. However,the maximum values of MAE and RMSE were observed at day 19, confirming the deviations shown in Fig. 5 at this time. However, the values of paired t-test between measured and simulated water contents showed insignificant differences at 5%level of significance at all times.Values of the coefficient of determination varied between 0.68 and 0.96, indicating a reliable generation of water contents by the model at all days of simulations. Similarly, the Nash and Sutcliffe efficiency coefficient values ranged from 0.17 to 0.96, indicating a good performance of the model for the prediction of water contents in this study.However,the relative efficiency value at day 19 reveals unsatisfactory performance of the model at that point according to the criteria suggested by Moriasi et al. . The values of MAE, RMSE, r2, E, and RE for the drainage flux were 2.87, 4.14, 0.97, 0.94, and 0.78 , respectively, which also showed a robust performance of the model for drainage fluxes from the lysimeter. The close match of both water contents and drainage fluxes indicates that the HYDRUS 2D/3D software can be successfully used to predict water movement and drainage fluxes in a lysimeter planted with a citrus tree. Other studies have also reported good performance of this software for various soil, water, and crop conditions under pressurised irrigation systems . Simulated water balance components over the 29 day experimental period are shown in Table 3. It can be seen that simulated drainage, which is similar to the amount measured in the lysimeter, represents 48.9% of the total water balance.

A much higher seasonal drainage has been reported for a lysimeter planted with an orange tree in a fine sandy soil . High drainage is bound to occur in highly permeable, coarse textured soils, such as the sand/loamy soil used in this study, where water drains easily and quickly from the root zone because gravity dominates over capillarity . However, Sluggett estimated deep drainage in the range of 6.1–37.2% under citrus trees growing in light textured soils in the Sunraysia region of Australia. A major contributor to the high drainage measured in this experiment was the high amount of water applied, mostly as a result of large rainfall events. Simulated plant water uptake was estimated to be 40% of the water application, indicating low irrigation efficiency of the drip system. The daily plant uptake varied from 1.2 to 3.14 mm . However, plant uptake is a very complex process, and depends on a number of parameters describing the root and canopy development. Since the HYDRUS model does not support a dynamic behaviour of the root system and considers only the static root parameters, root uptake was optimised on the basis of a changing transpiration rate over time. Additionally, since in the present study we dealt with a tree, for which the root distribution development over time is not as fast as observed for seasonal crops like cereals, the root development was considered relatively constant for the modelling purpose. Hence, a static root distribution and variable atmospheric conditions produced a good approximation of plant uptake, as has been revealed in a number of earlier studies that used HYDRUS for modelling purposes Simulated distribution of nitrate at selected times after commencement of fertigation is shown in Fig. 8. Concentration of NO3-N was maximum at the centre of the plume below the dripper, with a gradual decrease in N concentration towards the outer boundaries of the plume. Subsequent irrigation and fertigation pulses resulted in enlargement of the plume, with a rapid lateral and vertical movement of NO3-N. It is worth noticing that after 15 days of fertigation all nitrate still remained in the lysimeter, reaching a depth of 70 cm. The maximum nitrate concentration at this time was at 20 cm. The simulated NO3-N uptake accounted only for 25.5% of applied nitrogen .

The remaining nitrogen was still available in the soil for plant uptake, provided it was not transformed by soil biological processes. No nitrate leaching was predicted by the model within this initial 15 day period. The total seasonal recovery of applied N amounts to 42.1% by the orange tree, while 7.7% of added NO3-N was retained in the soil atthe end of the season. These results agree with the findings of Paramasivam et al. who reported 40–53% nitrogen uptake in afield experiment on citrus. Similarly, Boaretto et al. showed 36% recovery of applied nitrogen by an orange tree in a lysimeter. The seasonal distribution of nitrate in the soil at 30-day intervals after the fertigation commencement is shown in Fig. 9.It can be seen that nitrate rapidly moved downwards and dispersed in the lysimeter, reaching a depth of 95 cm after 30 days. However, the zone of the maximum concentration remained close to the soil surface. Subsequent fertigation pulses further pushed N near to the leaching outlet at 60 days and N dispersed throughout the lysimeter, beyond which regular N leaching was observed with subsequent fertigations. However, the concentration of N remained much higher in the upper soil depth till 180 days of fertigation, enabling its continued uptake by the orange tree. The nitrogen concentration thereafter reduced drastically in the upper zone as a result of the withdrawal of fertigation after 195 days of simulation . At 210 days after commencement of fertigation ,nft hydroponic system the NO3-N concentration in the domain ranged between 0 and 0.4 mg cm−3, and continued to decline until it completely moved out of the upper 40 cm soil depth at 270 days. At the end of the simulation , only a very small amount of nitrate remained in the lysimeter, with higher concentration occurring at the bottom of the lysimeter , indicating higher vulnerability of this N to leaching. Major leaching of NO3-N took place after 90 days of simulation, amounting to 61%of total N leaching between 90 and 180 days , which corresponds to heavy precipitation of 95 mm on day 115 and 68 mm on day 152 of simulation. Paramasivam et al. and Nakamura et al. also reported that unexpectedly prolonged irrigation or high rainfall following fertilizer applications led to higher NO3-N leaching losses.

Total nitrate leaching amounted to 50.2% of the N applied as fertilizer . Nitrate losses of similar magnitude have also been reported by Syvertsen and Sax and Boman and Battikhi in a lysimeter grown orange tree. On the other hand, low NO3-N leaching losses ranging from 2 to 16% of the applied nitrogen have been reported in some studies on citrus . The migration of nitrate to deeper layers is highly dependent on the amount of irrigation and rainfall, as this is the driving force moving nitrate out of the root zone. Lower nitrate leaching estimated in this study may have been a consequence of improved irrigation and fertilizer management through the drip system. Hence improved water efficiency under drip irrigation, by reducing percolation and evaporationlosses, can contribute considerably towards environmentally safer fertilizer applications . In addition to the factors discussed above, a choice of appropriate source, amount, frequency, and timing of fertilizer applications and the rate of N transformation into NO3 are other important factors that determine the amount of NO3-N leaching out of the vadose zone .Temporal distribution of nitrate for different fertigation scenarios is presented in Fig. 11.Although nitrate movement appears to be similar in all scenarios, small differences can be observed in nitrate distribution in the soil for some scenarios. In scenarios PF and PF3, in which fertilizer was applied with all pulses in low concentrations or towards the end of irrigation, the N concentration after 2, 7, and 14 days was slightly higher in the centre of the plume where root activity was at a maximum. However, the nutrient uptake varied within a narrow range under normal irrigation , indicating an insignificant impact of fertigation timing under conditions experienced in our lysimeter study. Contrary to this, Hanson et al. reported 14% higher nitrate uptake when fertilizer was applied at the end of the irrigation event in a HYDRUS simulation that was based on historical irrigation and fertigation data. A similar observation was also made by Paramasivam et al. and Alva et al. in field experiments. Gärdenäs et al. also concluded that fertigation applied towards the end of the irrigation cycle generally reduces the potential for nitrate leaching under micro-irrigation systems, with the exception of clayey soils.A short fertigation pulse used in our study, as compared to the other studies, may have reduced differences among various scenarios. However, these results imply that fertigation in a short pulse towards the end of the irrigation event or low concentration fertigation with all pulses could increase the efficiency of nitrogen fertigation as compared to other options. Nitrate distribution in the domain after 21 and 28 days were similar in all scenarios , and all differences disappeared by 21 days of simulation. It can be shown that while nitrate distribution varied during one application phase, they were similar for all scenarios at the end of each irrigation cycle. Also, nitrate moved to a similar soil depth after 28 days in all scenarios. These scenarios did not produce any NO3-N leaching because of the short simulation period. A comparison of nitrate uptake between pulsed and continuous irrigations revealed that scenarios with pulsed irrigation had almost alike nitrate uptake as fertigation with continuous irrigation. Similar results were obtained in scenarios with different irrigation quantities. A negligible impact of pulsing on moisture distribution pattern and drainage has been reported in earlier studies for different dripper discharge rates and spacings . This observation further confirms that pulsing has little impact on solute distribution in the soil under optimal irrigation applications as compared to continuous irrigation.Modelling simulations were also performed to evaluate the impact of variable irrigation applications on nitrate movement for scenarios discussed above . It can be seen that plant NO3- N uptake gradually reduced as the amount of irrigation increased. The nitrogen uptake efficiency for the 50% irrigation treatment varied from 55.3 to 56.2% for all scenarios of fertilizer applications, which was about 8.5% higher than uptake recorded for the normal irrigation . On the other hand, a higher amount of irrigation than normal reduced nitrate uptake of an orange tree by further 3.4–3.6%. At the same time, the zone of maximum nitrate concentration moved to a depth of 40–60 cm , where root uptake decreased exponentially due to the reduction in root density.

In an NFT hydroponic system, the pump should run continuously to maintain a consistent flow of nutrient solution over the roots of the plants. The continuous flow ensures that the plants receive a constant supply of water and nutrients while allowing for proper oxygenation of the roots.

Running the pump continuously helps prevent the roots from drying out and ensures a consistent nutrient delivery. It also aids in maintaining a stable root zone temperature. The continuous flow of nutrient solution in the NFT channels creates a thin film of liquid that flows over the roots, providing them with the necessary moisture and nutrients.

Therefore, it is recommended to run the pump in an NFT system 24 hours a day, seven days a week. This ensures that the plants receive a consistent supply of nutrient solution and promotes healthy growth. However, it’s important to monitor the nutrient solution levels and the overall health of the plants regularly to ensure optimal conditions and make any necessary adjustments.

Cucumbers can be successfully grown using various hydroponic methods. Here are a few ways to grow hydroponic cucumbers:

1. Nutrient Film Technique (NFT): Cucumbers thrive in NFT systems. Set up sloped channels or troughs for the plants to sit in, allowing a thin film of nutrient-rich water to flow continuously over the roots. Ensure proper support for the cucumber vines as they grow, as they can become heavy.
2. Deep Water Culture (DWC): DWC is another suitable method for growing cucumbers hydroponically. Use floating rafts or platforms to support the cucumber plants with their roots submerged in the nutrient solution. Oxygenate the solution adequately to promote healthy root growth.
3. Drip System: Drip irrigation works well for cucumbers. Place drip emitters near the base of each plant, providing a slow and steady supply of nutrient solution directly to the root zone. This method ensures efficient nutrient delivery while avoiding excessive moisture.
4. Aeroponics: Although less commonly used for cucumbers, aeroponics can be experimented with. Suspended cucumber roots in air and periodically mist them with a nutrient solution. Ensure that the mist droplets reach the roots for nutrient absorption.
5. Tower Gardens or Vertical Systems: Cucumbers can be grown in vertical hydroponic systems, utilizing tower gardens or stacked layers. These systems optimize space by growing plants vertically and provide support for the cucumber vines to climb as they grow.
6. Greenhouse Hydroponics: Hydroponic cucumber production is often done in controlled greenhouse environments. Greenhouses offer ideal conditions, including temperature and humidity control, for cucumbers to thrive. Various hydroponic systems, such as NFT or DWC, can be implemented within a greenhouse setup.

Remember to select cucumber varieties suitable for hydroponic cultivation, maintain proper nutrient balance, monitor pH and EC levels, provide adequate support for the plants, and ensure proper lighting and ventilation for optimal growth.

In an NFT (Nutrient Film Technique) hydroponic system, the height that lettuce can grow largely depends on the specific variety of lettuce and the conditions provided within the system. However, lettuce generally doesn’t grow to great heights compared to other plants.

Most lettuce varieties are considered leafy greens and have a compact growth habit. Under optimal conditions, lettuce typically reaches a height of 8 to 12 inches (20 to 30 centimeters). However, there are some varieties, such as romaine lettuce, that can grow slightly taller, reaching around 18 inches (45 centimeters) or more.

It’s important to note that in an NFT system, the focus is primarily on the growth and development of the leafy parts of the plant, rather than its overall height. Lettuce is typically harvested when the leaves have reached a desired size and before they start to bolt (produce flowers and go to seed). Regular harvesting of outer leaves promotes continuous growth and allows the plant to produce new leaves.

Maintaining proper nutrient levels, light intensity, and temperature within the NFT system is crucial to ensure optimal growth and prevent any potential issues that may limit lettuce height. Monitoring and adjusting these parameters based on the specific variety and environmental conditions will help you achieve the best results.

Building your own NFT (Nutrient Film Technique) hydroponic system for growing plants is an exciting project. NFT systems are efficient and effective for growing a variety of plants, including herbs, leafy greens, and even strawberries. Here’s a general guide to help you build your own NFT hydroponic system:

1. Materials you’ll need:
   • NFT channels or gutters: These are typically made of PVC or plastic and provide a channel for nutrient-rich water to flow through.
   • Water reservoir: A container to hold the nutrient solution that will be circulated through the NFT system.
   • Submersible water pump: This will pump the nutrient solution from the reservoir to the NFT channels.
   • Tubing and fittings: Connect the pump to the NFT channels and allow the water to circulate properly.
   • Growing pots or net cups: These will hold the plants in place and allow the roots to access the flowing nutrient solution.
   • Growing medium: Choose a medium that is suitable for NFT systems, such as rockwool cubes or grow plugs.
   • Nutrient solution: A balanced mix of hydroponic nutrients suitable for the plants you intend to grow.
   • Timer: Use a timer to control the pump’s schedule, ensuring regular cycles of nutrient flow.
2. Setup:
   • Determine the size and layout of your NFT system based on the available space and the number of plants you want to grow.
   • Install the NFT channels or gutters at a slight angle, allowing the nutrient solution to flow and create a thin film along the bottom of the channel.
   • Connect the water pump to the water reservoir using tubing and fittings. Ensure the pump is submerged in the nutrient solution.
   • Position the pump in a way that allows it to push the solution up to the highest point of the NFT channels, and let it flow down by gravity.
   • Place the growing pots or net cups in the NFT channels, ensuring the roots will hang down into the flowing nutrient solution.
   • Fill the pots or net cups with the chosen growing medium, such as rockwool cubes or grow plugs.
   • Set up the timer to turn on the pump for a specific duration and frequency, allowing the nutrient solution to flow through the NFT channels and then drain back into the reservoir.
3. Nutrient solution and maintenance:
   • Mix the appropriate hydroponic nutrient solution according to the instructions on the nutrient product.
   • Monitor the pH level and adjust it to the optimal range for your plants. Most plants prefer a pH range between 5.5 and 6.5.
   • Regularly check the nutrient solution levels in the reservoir and maintain the appropriate concentration by adding fresh solution or adjusting as needed.
   • Inspect the system regularly to ensure there are no clogs or leaks, and make any necessary adjustments.
   • Prune and maintain your plants as they grow, removing any dead leaves or overcrowded growth.

Remember that building and maintaining a hydroponic system requires attention to detail and ongoing monitoring. It’s essential to research the specific requirements of the plants you intend to grow, as different plants have varying nutritional needs and growth habits. Consulting resources and guides on NFT hydroponic systems can provide you with more detailed instructions and troubleshooting tips to maximize your success.

The resolution of the present study is relatively low compared to the 70% resolution reported by Fazekas et al. or other plant groups . Factors specific to the evolution of the Pulsatilla and/or the sampling strategy of this study may affect the ability to discriminate between species. Such factors include incomplete lineage sorting and hybridization, the rapid radiation of Pulsatilla species, the variation present at the barcode loci, and the sampling density used in this study. Unlike animal species, many plant species have paraphyletic or polyphyletic origins due to the higher frequency of reticulate evolution, which is facilitated by hybridization and polyploidization . Given that this is the case, barcoding based solely on plastid markers may not reliably distinguish species. For example, in our study, some species are resolved to paraphyletic groups, such as P. patens. In these cases, the use of nuclear DNA sequences may improve the resolution among plant species because nuclear loci have higher overall synonymous substitution rates, thus making nuclear markers such as ITS more sensitive. In our study, P. patens samples, and formed a monophyletic group with sample P. latifolia. However, these samples were not clustered together by chloroplast marker data .Manipulating the innate immune system of insects as a means of inhibiting vector acquisition of pathogens is currently being explored in many insect vectors of human pathogens. To apply these techniques to hemipteran vectors of plant pathogens, the immune systems of these insects must first be understood. The two hemipterans that have been investigated, the pea aphid and brown plant hopper,square pot have differing immune capabilities; with the brown plant hopper having a robust immune system similar to other insects; while the pea aphid has a drastically reduced immune system.

To identify if immune manipulation could be a technique used to inhibit the Asian citrus psyllid transmission of Candidatus Liberibacter asiaticus , we annotated the immune genes of ACP and exposed ACP to different classes of bacteria. Genome annotation revealed a substantially reduced immune system in ACP with an absence of recognition proteins in the classes PGRP and GNBP, the majority of the IMD pathway, and few genes for antimicrobial effectors. These results suggest that ACP have a particularly reduced immune response against gram-negative bacteria. When ACP were exposed to either gram-negative bacteria or grampositive bacteria through oral infections or cuticular punctures, significantly increased mortality was observed in response to gramnegative bacteria. Taken together, the genetic data and the controlled infection results indicate that ACP are not able to detect or eliminate gram-negative bacteria such as CLas. Although innate immune manipulation may have limited utility for inhibiting CLas acquisition by ACP based on these findings, microbial insecticides may prove to be an effective control technique for ACP. Currently, HLB is associated with Candidatus Liberibacter spp., although several phytoplasmas have been found in citrus showing HLBlike symptoms. The aim of this study was to determine if, in addition to Ca. L. asiaticus , phytoplasma species are also associated with HLB in citrus of Mexico. Citrus plants showing HLB-like symptoms were collected in the Mexican States of Nayarit, Colima, and Sinaloa between August 2011 and September 2012. Samples were evaluated for CP and CLas by nested-PCR and conventional PCR, respectively. For actual RFLP, phytoplasma fragments were digested with restriction endonucleases and fractionated using a QIAxcel system . Virtual RFLP analysis was performed on the 16SrDNA sequences using the virtual gel plotting program pDRAW32 . Phylogenetic trees were constructed with the NeighborJoining method, using the MEGA program . A total of 86 HLB-symptomatic samples of Mexican lime , Persian lime , and Valencia sweet orange Osbeck were analyzed. Diffuse chlorosis, blotchy mottle and vein yellowing were symptoms observed, even though we were unable to clearly identify symptoms specifically associated with either bacterium alone or together. Fifty-four out of 86 citrus plants were positive for CLas, 20 were positive for CP, seven were found in mixed infections with both pathogens, and 19 samples were negative for CLas and phytoplasmas.

Actual and virtual RFLP analyses of the 16S rDNA sequences enabled us to classify two HLB phytoplasma strains as members of the aster yellows group Candidatus Phytoplasma asteris , the subgroup B from Nayarit and subgroup S from Colima and Sinaloa, which was confirmed by phylogenetic analysis. In addition, the partial CLas sequences were identical to the strains isolated from several countries affected by HLB. These results confirm the association of CPa with HLB in citrus in Mexico. Huanglongbing , presumably caused by Candidatus Liberibacter asiaticus , is a devastating citrus disease associated with of flavor in orange juice. Relative CLas titer was determined by analyzing the 16S rDNA gene and the LJ primer targeting the CLas prophage in fresh or processed/pasteurized orange juice using qPCR. A method was developed that yielded large quantities of highly purified DNA, using only a small quantity of juice, which was then compared to the sensory characteristics of the juice using linear regression. To this end, orange juice was centrifuged and the pellet was used for qPCR analysis. After lysing the cells in an alkaline and non-ionic detergent Tris-based buffer, the initial DNA precipitation step was accomplished using hexdecetyl trimethyl ammonium bromide and sodium chloride at low concentration to remove polysaccharides like pectin. A trained sensory panel analyzed the same juice for various descriptors for flavor, aroma, mouthfeel, and aftertaste and the chemical components of the juice were also evaluated. By using multiple dilutions of a known amount of standard DNA, a standard curve was generated for log concentration of sensory descriptors against Ct. The amount of nucleic acids in an unknown sample can then be calculated from its Ct value. For the Li primers, Ct values between 35 and 30 indicated a minor decrease in juice flavor quality, but below 30 indicated a more significant flavor decline. Values below 30 indicated flavor decline for the LJ primer in relation to sweet taste or overall orange flavor and conversely to typical HLB flavor scores . This technology also worked for off-flavor causing microorganisms and human pathogens, for example Alicyclobacillus acidoterrestris or Escherichia coli, respectively, in orange juice or apple cider.An opportunity to analyze spatial patterns to determine the underlying biological process has developed from the widespread sampling and testing of Asian citrus psyllids in Texas and California to locate early infections of Huanglongbing disease. The real-time polymerase chain reaction diagnostic methods used to detect the casual agents of HLB, Candidatus Liberibacter asiaticus, are set to run for 40 cycles. The reaction must surpass a set threshold prior to the completion of the run to be considered positive for the presence of CLas.

When diagnostic testing of ACP initially started in Texas and California, the threshold had to be reached at <32 cycles and then later was raised to <37 cycles. Currently,black plastic pots for plants reactions that surpass the threshold at 37 or more cycles have proven impossible to acquire confirmatory conventional PCR bands and DNA sequence data. Thus, these samples are classified as inconclusive. The question we are trying to answer is whether information in the Ct-values between 37 and 40 is also useful for predicting locations with HLBinfected citrus plants. Analysis of 2013 data from California indicates that psyllid samples with high Ct-values tend to be clustered at close ranges and then dispersed at larger scales. Clustering of samples with Ct-values in the 38-39 range is within 1 km of samples with Ct-values below 37. In both Texas and California, spatial clustering of psyllid samples with inconclusive Ct-values have been shown to cluster around known positive HLB-infected trees. One of the main obstacles in advancing the search for antimicrobials against ‘Candidatus Liberibacter asiaticus’ is the inability to culture this pathogen to perform classical growth inhibition tests. Consequently, we centered our research in the identification of chemicals that inactivate critical physiological pathways operating in this bacterium. To achieve our goal, the experimental design used in our laboratories consisted of a deep in silico multifactorial genomic analysis, followed by a conventional biophysical screening of selected targets. Using this approach, we identified new chemicals that targeted a transcriptional regulator belonging to the MarR-family in CLas. The DNA binding sequence of LdtR was identified via DNase I footprinting. In silico analyses using this binding site indicated that LdtR modulates the expression of several genes involved in cell division and cell wall biosynthesis. A gene of particular interest within the regulon is ldtP, which is predicted to encode for an L,D-transpeptidase. This enzyme is involved in the modification of the bacterial cell wall using an alternative pathway and it is resistant to the activity of b-lactam antibiotics. A recombinant LdtP enzyme has been purified and used as a target to identify potential enzymatic inhibitors. Herein, we present the impact of the identified new antimicrobials on the regulatory activity of LdtR and on the enzymatic activity of LdtP. The compounds identified represent an important advance in the identification of chemicals to be used as bactericidal in planta. The results herein described provide important insights to understand CLas regulatory networks and molecular foundations for the design of therapeutics for the treatment of this devastating disease. Since HLB was first reported in Brazil , the EEAOC implemented and strengthened different lines of work in four strategic areas. Provision of sanitized and certified vegetal material: EEAOC is the only sanitation center in northwestern Argentina and is in charge of providing sanitized and certified material to citrus nurseries. Observation and monitoring: a molecular diagnosis laboratory was set up for Candidatus Liberibacter spp. detection for both vegetal and insect samples.

We visually inspected citrus trees from 44 places located in Northwest Argentina and collected leaf samples, displaying HLB-similar symptoms, and insect samples. From 2005 to present, 12,500 samples were analyzed by qPCR TaqMan, 50% corresponded to citrus leaf, 46% to insect, and the remaining 4% to ornamental plants. All samples were negative. To date, there is no evidence that Candidatus Liberibacter spp. are in the NOA; although, 3,000 sticky traps for Diaphorina citri were set across the citrus area in Tucumán province and checked periodically. Furthermore, citrus plantation and alternative hosts in the urban area were monitored too. This monitoring was conducted on a weekly basis, but was intensified in spring and summer. In April 2011, the abovementioned activities resulted in the detection of 11 D. citri specimens on Murraya paniculata plants from the urban area. This case has remained under effective control by the national and provincial phytosanitary authorities and has not led to any subsequent reports. As for the citrus area, over 600,000 shoots and approximately 25,000 colored sticky traps have been checked without detecting the insect vector. These results prove that Tucumán province is free from D. citri. In the north of NOA , where the insect is present, the efficiency of 17 active ingredients was evaluated along with their correspondent fresh fruit residue analysis.One of the principal challenges in managing rapidly spreading epidemics is to identify optimal control strategies. How, when, where, and which control methods should be used to manage disease effectively. Epidemiological modelling can help by providing a means to integrate the current status of knowledge and to provide a set of tools to compare the effectiveness of different control scenarios. The epidemiological approach is also well-suited, taking account of uncertainties in order to inform a risk‐based management of disease. Drawing upon experience gained from modelling a range of emerging pests and pathogens including Huanglongbing and Asian Citrus Psyllid , I propose to show how an ‘epidemiological toolbox’ can be used to predict disease and vector spread, to analyse the effectiveness of control and to compare ‘what‐if’ scenarios for disease management. Successful control of disease requires us to match the scale of control with the inherent spatial and temporal scales of the epidemic. Identification and characterisation of the epidemic scales involve the formulation of mathematical models that capture the essential biological features of disease spread. The spatial distribution of hosts in the landscape is also important along with the effects of environmental variables and anthropomorphic activity, and the degree of stakeholder compliance. Using data for the spread of disease in Southern Gardens and data from psyllid traps in California, I propose to show how it is possible to extract signatures in the form of epidemiological parameters such as transmission rates and dispersal kernels for epidemic and vector spread.

We examine how the last three recessions affected hourly earnings, the probability of receiving a bonus, and weekly hours in agricultural labor market. We compare those results to those in three non-agricultural labor markets that rely on immigrants. We empirically test five hypotheses. first, we expect seasonal agricultural workers’ earnings to rise during major recessions. Because the income elasticities of demand for seasonal agricultural products such as fruits and vegetables are relatively inelastic, recessions cause a small, possibly negligible leftward shift of the labor demand curve in seasonal agriculture. In contrast, a recession’s may cause a significant leftward shift of the labor supply curve. Roughly half of hired, seasonal agricultural workers are undocumented.The Great Recession significantly reduced the number of new, undocumented immigrants entering the United States , causing a substantial leftward shift of the agricultural labor supply curve.Given a substantial leftward shift of the supply curve and only a minimal shift of the demand curve, agricultural workers’ earnings rise. Second, while we hypothesize that hourly earnings and the probability of receiving a bonus rose during the Great Recession, 2008–2009, we expect these earnings measures to rise by less or possibly fall in the earlier,drainage planter pot relatively minor 1990–1991 and 2001 recessions. The Great Recession caused much larger decreases in new immigrant labor supply than in these earlier recessions . Third, we expect recessions to affect undocumented workers differently than documented workers because their labor markets are partially segmented.

Evidence that these markets are partially segmented comes from earlier studies that show that, compared to documented workers, undocumented workers are more likely to be employed by farm labor contractors as opposed to farmers, and because their pay differs . Fourth, we expect weekly hours of employed agricultural workers to increase to compensate for the reduced flow of new immigrants during major recessions. Fifth, we expect recessions to have larger earnings effects in agricultural labor markets than in construction, hotel, and restaurant labor markets. These non-agricultural labor markets are more likely to have sticky wages due to union and other contracts and minimum wage laws. The first section discusses how recessions affect the supply curve of agricultural labor. The next section describes our two data sets. The third section presents our empirical results. The final section discusses our results and draws conclusions.In contrast, during a major recession, fewer undocumented immigrants enter the United States from Mexico and other countries. Passel, Cohn and Gonzalez-Barrera reported a large drop in the number of undocumented immigrants during the Great Recession relative to the recovery years afterward and to preceding years, which include milder recessions. They estimated that the number of undocumented immigrants rose monotonically from only 3.5 million in 1990 until it peaked at 12.2 million in 2007. However, the number of immigrants fell to 11.3 million by 2009 during the Great Recession. In contrast, they found that the supply of immigrant labor rose during relatively mild 2001 recession.These results are consistent with U.S. border patrol reports from the Department of Homeland Security’s Office of Immigration Statistics. Apprehensions by the U.S. border patrols dropped from 876,803 in 2007 to 556,032 in 2009. Because immigrants often send money home, we can use remittances from the United States to Mexico to infer whether the number of immigrants changed substantially during a recession. Figure 2 shows quarterly remittances to Mexico in millions of U.S. dollars as reported by Banco de México .

The figure shows that remittances increased during the relatively mild 2001 recession but decreased substantially during the 2008–2009 Great Recession. These data again support the view that the number of Mexican immigrants to the United States fell during the Great Recession but not during the previous, milder recession. Moreover, Warren and Warren estimated that the net change of undocumented immigrants was negative during the Great Recession, which was related to a sharp decrease of new undocumented immigrants. The United States Department of Agriculture, Economic Research Service estimated number of full- and part-time agricultural workers fell from 1.032 million in 2007 to 1.003 million in 2008 and 1.020 million in 2009, before rising to 1.053 million in 2010.5 That is, the number of workers in 2008 was 3% to 5% lower than in the years before and after the Great Recession. Presumably the share of workers dropped by even more in seasonal agriculture, which employs most of the undocumented workers.The NAWS is an employer-based survey. That is, it samples worksites rather than residences to overcome the difficulty of reaching migrant farm workers in unconventional living quarters. These employers are chosen randomly within the U.S. Department of Agriculture’s 12 agricultural regions .Surveyors randomly select 2,500 employees of these growers to obtain a nationally representative sample of crop workers. Surveyors interview the more than 2,500 crop workers outside of work hours at their homes or at other locations selected by the respondent. The NAWS has a long, visible history within farming communities, and the survey design incorporates questions aimed at data validation about legal status.As a result, only one to two percent of workers in the overall sample refuse to answer the legal status questions. The NAWS contains extensive information about a worker’s compensation, hours worked, and demographic characteristics such as legal status, education, family size and composition, and workers’ migration decisions. We dropped workers from the sample who were missing any relevant variable, 23% of the original survey sample.

The NAWS is conducted in three cycles each year year to match the seasonal fluctuations in the agricultural workforce. Unfortunately, the public-use data,which we use, suppresses information about the cycle and aggregates the 12 regions into 6 regions. As a result, our data set consists of repeated annual cross sections of workers from 1989 through 2012. Column 1 of Table 1 presents national summary statistics for the variables used in our empirical analysis. Columns 2 and 3 provide data for California and for the rest of the country, because 37% of the sample works in California. Compared to workers in the rest of the country,plant pot with drainage Californian workers tend to have less education; have more farm experience; are more likely to be non-native, Hispanics; and are more likely to work in fruit and nut crops and less likely to work in horticulture. After analyzing the effects of recessions on agricultural workers, we replicate the analysis for workers in construction, hotels, and restaurants, which also employ many immigrants. The data for workers in these sectors come from the March Current Population Survey . In March of each year, workers in the basic CPS sample are administered a supplemental questionnaire in which they are asked to report their income such as hourly wage rate and additional labor force activity such as hours worked in the previous week.8 Because information on immigration is available only since 1994, our sample period is 1994–2013. We include all workers who are 18 years and older.Three recessions occurred during our 1989–2012 sample period . The economy recovered quickly from the first of these recessions in 1990–1991. The second, 2001 recession was also relatively mild. However, the third recession, the 2008–2009 Great Recession, was much more severe and had longer-lasting economic and labor market effects than the first two. We analyze the effects of recessions on hourly earnings, the probability of receiving a bonus, and weekly hours of work of employed workers. For workers paid by time, hourly earnings are a worker’s hourly wage. For piece-rate workers, we use the workers’ reported average hourly earnings. The bonus dummy equals one for workers who receive a money bonus from an employer in addition to the wage, and zero otherwise. Weekly hours of work are the number of hours interviewees reported work at their current farm job in the previous week. The explanatory variables in all these equations are the same. The explanatory variables include all the usual demographic variables: age, years of education, years of farm experience, job tenure , gender, whether the workers is Hispanic, whether the worker was born in the United States, and whether the worker speaks English.The specification uses a legal status variable to capture the bifurcated labor markets for documented and undocumented workers. It also includes crop and regional dummies.

We have seven main explanatory variables: dummies for each of the three recessions, the recession dummies interacted with the legal status dummy , and regional unemployment rates for workers in all sectors of the economy. We use separate dummies for each recession to allow for differential effects across the recession . The interaction terms capture whether employers treat undocumented workers differently than legal workers during a recession. We include the unemployment rate because it peaks after the end of each recession . We do not report the unemployment rate interacted with the undocumented dummy because we cannot reject that its coefficient is zero in any equation. We treat all these variables as exogenous to the compensation and weekly hours of individual agricultural workers. We start by examining the effects of recessions on NAWS workers’ hourly earnings. Column 1 of Table 2 presents regression estimates for the ln hourly earnings equation. The coefficients on the demographic variables have the expected signs and are generally statistically significantly different from zero at the 5% level. Undocumented workers’ hourly earnings are 2.1% less than those of documented workers. Females earn 6.4% less than males. Hispanics earn 4.9% less than nonHispanics. Unlike most previous studies, we find a statistically significant effect of education. English speakers earn 3.9% more than non-English speakers. The coefficients on the recession dummies reflect the effect of the recession on documented workers. Documented workers’ hourly earnings rose 1.8% during the 1990–1991 recession, 4.2% during the 2001 recession, and 6.9% during the Great Recession. We draw two conclusions about the effects of recessions on documented workers. first, the hourly earning effect of the Great Recession was larger than that of the relatively minor recessions, which is consistent with literature on business cycles and the farm labor market in the 1970s . Second, in all recessions, documented workers’ wages rose, which suggests that recessions cause the hired-agricultural-worker supply curve to shift leftward relatively more than did the demand curve. The sum of the coefficients on the recession dummy and its interaction with the undocumented dummy captures the effect of a recession on undocumented workers. The 1990–1991 recession did not have a statistically significant effect on undocumented workers. Hourly earnings for undocumented workers rose by 3.4% during the 2001 recession and 1.9% during the Great Recession. In contrast to the pattern for documented workers, the undocumented workers’ earnings rose by less during the Great Recession than during the 2001 recession. Thus, not only do undocumented workers earn less than documented workers do in general, but their hourly earnings rise less during recession than do the earnings of documented workers. That is, the wage gap between documented and undocumented workers widens during recessions. In addition to hourly earnings, 28% of the workers in our sample receive bonus payments , which supplement relatively low wage payments . These deferred payments play a similar function to that of efficiency wages in other sectors . We use a binary indicator equal to one if a worker receives a money bonus. Column 2 of Table 2 shows the results of a regression using a linear probability model . For documented workers, the probability of receiving a bonus did not rise during the two relatively minor recessions but increased by 5.8 percentage points during the Great Recession. Thus, the Great Recession not only raised documented workers’ hourly earnings, but it raised the probability that they received a bonus substantially. For undocumented workers, the probability of receiving a bonus fell by 2.9 percentage points during the 1990–1991 recession and rose by 9 percentage points during the Great Recession. Again, this result is consistent with the theory that the Great Recession caused a large supply side shock. Thus, for both documented and undocumented workers, the Great Recession had a larger, positive effect on the probability of receiving a bonus than did earlier recessions. The unemployment rate has a statistically significant effect on the probability of receiving a bonus payment.

The role of Pv08 in the original domestication of Middle American common beans also cannot yet be ruled out. Our Pv03 QTL mapping peak in the MxB population was closer in physical distance to PvPdh1 than what has been previously identified through QTL mapping in a different recombinant inbred population—ICA Bunsi x SXB405 . These results are still not as close to the gene as those achieved by GWAS with a much larger SNP dataset . The correlation between PvPdh1 allele and pod twists indicates that the gene may modify the twisting force of pod walls. This has been seen in the soybean ortholog as well as across numerous legume species . The complex dominance of PvPdh1-mediated shattering resistance parallels the pattern seen in soybean pods, in which the phenotyping method affects the pattern of dominance . The desiccation method was faster to phenotype than counting pod twists and also produced results which were much more correlated with genotype. This indicates that the desiccator method may be a more effective method of phenotypic screening than counting twists. The recessive nature of pod shattering when phenotyped by the desiccator method means that carriers of the resistant Pvpdh1 allele may demonstrate high levels of pod shattering in early breeding program generations because of heterozygosity and should not be eliminated without direct genetic evaluation or subsequent progeny tests. Further,how to set up a vertical farm the recessive nature of shattering resistance when phenotyped by the desiccator method also indicates that recurrent back crossing based on phenotyping alone would not be practical for the trait.

Pvpdh1 therefore requires a genetic marker for screening of progenies that carry the shattering-resistance allele.Our results indicate that durable resistance to pod shattering has evolved independently in both the Middle American and Andean gene pools of common bean. Despite this, many varieties in both gene pools continue to display the wild type propensity to shattering, and this is strongly associated with market class. Our results agree with earlier anecdotal observations that pod shattering is most problematic in the black and cranberry market classes , the two categories with the highest rates of pod shattering in the MDP and ADP. In contrast, market classes with the lowest rates of pod shattering are those in which the resistant Pvpdh1 allele is most abundant . While direct comparisons between the Andean and Middle American gene pools are complicated by the fact that the populations were grown in different years, the desiccation treatment used to induce pod fracture was identical between populations. In any case, it is clear that many varieties of both gene pools experience high levels of pod shattering and would benefit from the introgression of shattering-resistance alleles. Market demands require most new varieties of common bean to conform to standards for several complex traits, such as seed size, shape, color, leading most modern breeding to focus preferentially on intra-race crosses. Marker assisted back crossing would greatly facilitate the transfer of the shattering-resistant allele into other ecogeographic races, while maintaining the complex genetic background required in a market class. A better understanding of the PvPdh1 locus, as well as molecular markers associated with it, will become increasingly important for crop improvement as conditions become more arid in the twenty-first century.Our haplotype diversity results are consistent with the hypothesis that there has been stronger selection pressure on PvPdh1 in race Durango than in race Mesoamerica.

After selection of the shattering resistant allele at PvPdh1, race Durango types differentiated into just two additional new haplotypes, which represent 3% of the group’s sampled varieties. The non-shattering character found in the low-frequency haplotypes indicates that these groups may have differentiated since the mutation in PvPdh1, rather than being ancestral reflicts of a shattering-susceptible race Durango progenitor. In contrast, race Mesoamerica includes six total haplotypes, and the ive least common of these together represent 7% of the sampled varieties. This is more than double the frequency of minor haplotypes than in race Durango. These less-common variants could be the subject of future study to identify whether secondary mutations in PvPdh1 have independently arisen to regulate pod shattering in a subset of varieties within race Mesoamerica.While EcoRI is a highly stable, robust enzyme, TaqII is a high molecular weight, lower-stability enzyme, which requires highly specific conditions for optimal DNA cleavage . This includes a predigestion PCR product cleanup and extreme care in handling of the enzyme. Although TaqII treatment always led to digestion of susceptible alleles, this digestion was sometimes only partial, leading to ambiguity between homozygous susceptible and heterozygous individuals. Further, the cleavage of shattering-susceptible alleles is generally less desirable than cleavage of resistant alleles to reduce the risk of selecting susceptible types due to technical errors. While the TaqII-based marker may be ideal for initial parental screening, the tightly linked EcoRI-based CAPS marker may be more practical for rapid, efficient screening of large breeding populations. The CAPS markers developed here may be valuable for rapidly transferring the pod-shattering resistance of race Durango into the market classes of race Mesoamerica and the Andean gene pool. Pod shattering is a complex quantitative trait and is regulated by multiple alleles and environmental variables. Indeed, selection based on phenotyping alone will not always be predictive of an individual’s susceptibility to pod shattering , leading to imperfect selection accuracy.

Our CAPS markers will provide a more accurate and rapid method to genetically evaluate an individual’s resistance to pod shattering. Similarly, the SNPs used to develop these CAPS markers could be converted to Kompetitive Allele specific PCR markers through commercially available services. Phenotypically, this trait cannot be measured until after plants have fully senesced, delaying selection and requiring breeders to invest heavily in non-desired plants. Further, it often requires additional heat treatment incubation periods or labor-intensive analyses with specialized equipment, such as mechanical force measurement gauges, to study accurately . In contrast, our genetic tests can be conducted rapidly on segregating populations of seedlings, reducing costs for breeding programs and hastening genetic improvement. These markers will also allow breeders to accurately pyramid shattering resistance alleles from the Andean and Middle American gene pools for the first time, potentially leading to stronger resistance to pod shattering than what is provided by Pvpdh1 alone. In turn, this will facilitate the development of varieties that are more tolerant of warm, dry environmental conditions where pod shattering is most problematic.Tolerance to desiccation can be defined as the ability of an organism to survive extreme dehydration and then to resume normal growth upon rehydration.Vascular plants with the ability to revive from extreme desiccation are commonly called as resurrection plants.3 To date, more than 300 angiosperms,what is vertical growing including a few dicotyledonous plants, have been identified as resurrection plants.Tolerance to desiccation in resurrection plants is a complex process that involves many physiological and metabolic mechanisms.The strategies adopted by resurrection plants to survive desiccation may resemble those seen in seeds.Water deficit is initially accompanied by osmotic adjustment to protect against cellular damage, which is accomplished by the accumulation of large amounts of sugars, amino acids, and small polypeptides such as late embryogenesis abundant proteins and dehydrins. Increasing water deficit results in the activation of mechanisms to cope with desiccation-induced structural and functional alterations of macromolecules and membranes, the accumulation of toxic substances and free radicals, and mechanical damage associated with the loss of turgor.Under desiccation stress, the oxidative damage caused by the production of reactive oxygen species is enhanced, especially in chloroplasts. Two different strategies are adopted by resurrection plants to minimize ROS damage. Homoiochlorophyllous resurrection plants conserve the structure of their photosynthetic apparatus, synthesize anthocyanins, and increase the activity of antioxidants during desiccation, whereas poikilochlorophyllous resurrection plants demolish chloroplast pigments and membranes, thus reducing cellular sources of ROS.6 Resurrection plants are excellent models for studying molecular mechanisms that could potentially serve as biotechnological tools for enhancing drought tolerance.There have been many studies of the molecular effects of drought on model plants such as Arabidopsis and rice,but information is scarce on the desiccation tolerance mechanisms of resurrection plants.Transcriptomics has been used to generate global gene expression atlases, such as for powdery mildew resistance,horticultural traits in apple,fruit ripening, and cherry fruit development.To understand desiccation tolerance mechanisms, transcriptomic and proteomic studies have been performed in resurrection plants such as Sporobolus stapfianus, Tortula ruralis, Xerophyta viscosa,and Boea hygrometrica.However, large-scale expressed sequence tag sequencing analysis using high-throughput sequencing and de novo assembly strategies have only been conducted in two herbaceous species, Craterostigma plantagineum and Haberlea rhodopensis.

Myrothamnus flabellifolia, a woody homoiochlorophyllous resurrection plant growing in the mountainous regions of central and southern Africa,is probably the most primitive angiosperm to show extreme tolerance to desiccation.It displays novel anatomical, ultra-structural, and biochemical adaptations to desiccation stress and has been the subject of a number of physiological and biochemical studies. Under severe drought conditions, M. flabellifolia leaves can become air-dry, folding in a unique fan-like manner.Upon rewatering, the leaves return to their original color and shape within 24 hours.Biochemical studies of the cell walls have demonstrated an abundance of arabinose polymer side chains, consisting of arabinans associated with the pectin matrix, which may explain the flexibility of the mesophyll cells, allowing leaf morphology to be rapidly recovered after rehydration.During desiccation, presumably to protect from ROS, the leaves synthesize large amounts of anthocyanins and change their color from green to dull-brown.High levels of phenols, including tannins, arbutin, and tri-O-galloylquinic acid, have been reported in the leaves of M. flabellifolia. Differences in phenolic content and composition may be associated with differences in tolerance to desiccation stress among populations of M. flabellifolia.Moreover, desiccated leaves of M. flabellifolia contain high levels of saccharides, although the precise constituents differ.The molecular mechanisms underlying the tolerance of M. flabellifolia and its ability to rapidly rehydrate are still largely unknown. In the present work, we attempt to investigate the transcriptome dynamics in response to dehydration and rehydration in M. flabellifolia. Most woody fruit and ornamental plants can encounter extreme drought stress. Therefore, understanding this plant’s extreme tolerance to desiccation and drought can aid the development of strategies for improving drought stress resistance in horticultural crops.To evaluate the potential functions of genes that showed significant transcriptional changes during dehydration and rehydration in M. flabellifolia, we examined the GO enrichment of DTGs at each dehydration and rehydration stage. The biological processes that were significantly enriched early in dehydration included many defense responses such as response to chitin, cold, wounding, and fungi . This is consistent with a previous transcriptomic study in the resurrection plant H. rhodopensis in which many genes involved in acquiring tolerance to a variety of abiotic and biotic stresses were induced by desiccation stress.In striking contrast, the DTGs represented in moderately dehydrated and desiccated leaves participate in photosystem II assembly, thylakoid membrane organization, chlorophyll biosynthesis, and photosynthesis . These data suggest that alteration of photosynthesis is an important strategy in response to desiccation for M. flabellifolia. Moreover, genes involved in isopentenyl diphosphate biosynthesis were enriched in moderately dehydrated, desiccated, and rehydrated leaves . Isopentenyl disphosphate is a precursor of all plant isoprenoids,which are a diverse group of metabolites including primary metabolites such as sterols, chlorophylls, carotenoids, quinones, and hormones and secondary metabolites participating in plant defense and communication such as pigments, volatiles, and defense compounds.To further delineate the metabolic pathways participating in the dehydration and rehydration responses, we mapped the DTGs into the Kyoto Encyclopedia of Genes and Genomes database. A total of 23 and 18 biochemical pathways were significantly enriched during dehydration and rehydration, respectively . During dehydration, consistent with the GO enrichmentanalysis, the enriched biochemical pathways involved diverse metabolites, including secondary metabolites, starch, sucrose, fatty acids, fructose and mannose, and photosynthesis, suggesting a global response to desiccation in M. flabellifolia. As one example, the flavonoid biosynthesis pathway was significantly enriched during dehydration, consistent with the role of anthocyanins, a flavonoid class, in the ‘green-to-brown’/‘brown-to-green’ leaf color alternation during dehydration and rehydration.During rehydration, photosynthetic genes were significantly enriched . This is consistent with a previous study in M. flabellifolia showing that photosynthesis resumes rapidly, reaching full capacity within three days of rehydration.The recovery of vital functions and metabolic activities during rehydration is indicated by alterations of genes encoding a range of structural and physiological processes.For example, genes encoding enzymes involved in ribosome and aminoacyl-rRNA biosynthesis, essential for the re-establishment of normal cellular metabolism, are enriched during rehydration .

A 0.5 μl sample was injected into the liner in splitless mode, and the liner was exchanged every ten samples. The injection temperature started at 50o C and ramped to 250o C by 12o C per sec. The GC column was a Rtx-5Sil MS at a constant flow of 1 ml min−1 helium gas. The column temperature started at 50o C for 1 min and then ramped to 330o C. Automatic mass spectral deconvolution was performed with peak detection of GC spectrum using The BinBase algorithm . After peak peaking, peak data were deposited BinBase DB with BinBase ID. BinBase settings: validity of chromatogram , unbiased retention index marker detection , retention index calculation by 5th order polynomial regression. Spectra are cut to 5% base peak abundance and matched to database entries from most to least abundant spectra using the following matching filters: equivalent to about ± 2 s retention time, unique ion must be included in apexing masses and present at > 3% of base peak abundance, mass spectrum similarity must fit criteria dependent on peak purity and signal/noise ratios . Failed spectra are automatically entered as new database entries if s/n > 25, purity < 1.0 and presence in the biological study design class was > 80%. Resulting .txt files were exported to a data server with absolute spectral intensities and further processed by a filtering algorithm implemented in the metabolomics BinBase DB .At the molecular level for resistance in initial infection stages,vertical farming equipments a lack of bacterial propagation, induction of vir, and incomplete integration of T-DNA result in crown gall resistance in grapevines . V. riparia that showed RR in our study had a broad range of crown gall resistance by particularly inhibiting the integration of A. vitis T-DNA into plant chromosome .

This type of resistance prevents the pathogen from infection, resulting in the reduced GI, leading to no or little gall development to have also lowered GDI, which may be applied as a major resistance mechanism for the four Vitis species of RR. For SR, GI was similar to SS, but GDI, to RR, suggesting the pathogen infection in SR occurs as in SS, but gall development is retarded as in RR to have moderate GSI between SS and RR. For SS, both A. vitis T-DNA integration into host genome and expression of encoded plant oncogenes and increase in phytohormone levels occur readily, resulting in the formation of tumors and their proliferation . Out of a total 134 metabolites produced in the grapevine stem internodes infected with A. vitis K306, 11 metabolites were significantly related with response types of 10 Vitis species examined in our study. At pre-inoculation stage, only one metabolite was significantly increased in RR relative to SR, while all 11 metabolites were significantly increased in either SS or RR at post inoculation stages, suggesting metabolic changes may occur preferentially around the infection sites after the pathogen infection, especially at initial stages of the pathogen infection with response type-related 8 metabolites, of which 6 related to SS but only 2 most significantly related to RR and SR . At post 2 , all three metabolites were more related to SS than RR or SR; however, at post 3 all three metabolites were more related to RR or SR than SR and/or SS. These all suggest that the metabolic changes occur actively in relation to susceptible responses at the initial stages after the pathogen infection, but in relation to resistant responses at later infection stages with full gall development.

An amine derivative, octopine, produced by the octopine-type A. vitis used in our study and two plant hormones, auxin and cytokinin, produced in the T-DNA transformed plant cells, drive the uncontrolled gall development, determining gall morphology depending on the ratios of the plant hormones . However, neither octopine and its amino acid component arginine nor the plant hormones were produced in a significant level around the infection sites in our study, suggesting the gall-inducing metabolites may hardly be transported out of the tumorigenic tissues. However, the component class most abundantly produced in relation to response types was amino acid in our study, including 4 amino acids produced at post 1 and one at post 3, which was significantly related to SS and RR, respectively. The functions of these amino acids in crown gall development have not been clearly understood, but amino acids are generally involved in the primary metabolism of all living organisms, and the developing tumor becomes a metabolic sink accumulating metabolites to be supplied in a priority for its growth by the induction of vascular tissue differentiation around gall surface . It was reported previously that three SS-related amino acids except tyrosine increase several folds in tumor tissue at later infection stage , suggesting also these SS-related amino acids should be related to the gall development, although the time for the production of the materials may differ depending on Agrobacterium species. Other component classes of the metabolites such as carbohydrates and carboxylic acids which were increased in SS at 2 and 7 days after inoculation, respectively, may also serve for the gall growth and differentiation by inducing vir genes; gallocatechin, a flavonoid, may be involved in the gall formation as a potential auxin transport regulator as in root nodulation and root-knot gall formation . Quinic acid, catechins, and stilbene are related to Pierce’s disease, showing these metabolites occur at great levels in xylem tissues of the grapevine infected with Xylella fastidiosa.

In plants, major resistance-related responses to Agrobacterium spp. occur at two periods of time, initially at the time of recognizing the tumorigenic pathogens and later during the time of the pathogenesis in which auxin and cytokinin cause an increase of ethylene that together with salicylic acid inhibits agrobacterial virulence . In our study, resveratrol at post 1 and valine and xylonic acid at post 3 were definitely differentiated as RR from the other response types . Resveratrol is a stilbenoid, a type of natural phenol, and a phytoalexin produced naturally by several plants in response to injury or pathogen infection . In grapevine, resveratrol is primarily found in the grape skin and produced as phytoalexin in grapes infected with the grey mold pathogen, Botrytis cinerea, of which the accumulation amounts vary with grapevine genotypes, their geographic origin, and exposure to fungal infection . Considering the biological characteristics of this stilbene compound , this metabolite may be produced in Vitis species with RR at a significant amount and act as a phytoalexin to inhibit the growth and virulence of the tumorigenic pathogen probably more at initial infection stages. For the other metabolites increased in Vitis spp. with RR at the later infection stages , valine , and xylonic acid ,vertical farms their roles in plant responses are not clearly understood. Alterations in the plant metabolism in response to different pathogen infections may function as either supporting the ongoing defense mechanism to lead an efficient resistance response or being exploited by the pathogen to facilitate infection as can be seen in plant glutamate metabolism . Thus, it is not an unusual thing that the metabolites in the same compound classes were differentiated in relation to the opposing response types; xylonic acid significantly related to RR at post 3, while quinic acid to SS at post 2; valine related to RR at post 3, while four amino acids to SS at post 1 in our study. Considering the same class metabolites concomitantly occurred in relation to different response types at different infection stages, the same class metabolites may play different roles depending on their requirements for in situ metabolism, leading to either compatible or incompatible responses to the pathogen infection In our study, sucrose contents were highest in grapevine stem internodes with SR at post 1 and post 3, which was significantly differentiated from SS at post 1 and RR at post 3, respectively . Considering the increased expression of sucrose degradation enzyme genes in gall tissues of Arabidopsis and its induction of Agrobacterium virulence genes , the increased sucrose contents may support its intake into the metabolic sink, crown gall tissue, contributing to the gall development in different degrees depending on infection stages . Host sucrose, synthesized from photosynthetic products in the cytoplasm of aerial plant parts, is transported to tumor cells apoplastically and the sucrose contents in phloem sap differ depending on the crown gall-developmental stages with higher around actively growing young galls than old matured ones .

In our study, the sucrose contents fluctuated with time after infection and were higher at post 1 than post 3, regardless of response types, suggesting the uptake of sucrose should be required for the gall development. Another carbohydrate cellobiose was significantly higher in RR relative to SR at preinfectional stages, but higher in SS than RR and SR at post 1, suggesting its roles in healthy plant tissues may alter oppositely in diseased plant tissues with uncontrolled gall development. In our study, metabolite profile analysis revealed the following aspects: Remarkable differential increases of metabolites occurred in internodes of Vitis species after A. vitis infection, most prevalently at two days after inoculation, and more related to susceptible type of response for 10 metabolites that are useful for the metabolic processes in gall growth and differentiation as nutritional compounds or plant hormone regulator. Among three metabolites definitely differentiated into the resistant response , resveratrol appeared to be importantly related to resistant responses as it is a well-known phytoalexin compound in several plant pathosystems. All of these aspects will provide important information that can be applied for the selection of grapevine cultivars resistant to the crown gall disease caused by A. vitis, and their use as root stocks for the control of the crown gall disease in the scions of the grapevines susceptible to A. vitis. Abscission is the process of organ separation, which plays a critical role in the plant life cycle. Organ shedding occurs at abscission zones , comprising small, densely cytoplasmic cells at the boundary between an organ and the main plant body. Abscission has evolved as a successful strategy to adapt to the environment in response to developmental and environmental cues. Abscission allows plants to detach nonfunctional or diseased organs and is also important for seed dispersal. The timing of abscission, especially of flower and fruit abscission, is of interest to agriculture. Breeding of appropriate abscission behavior has successfully solved crop production and yield problems such as grain shattering, cotton boll shedding, premature legume dehiscence, and mechanical harvest in tomato. It has been well-demonstrated that the timing of abscission is regulated by cross-talk between the phytohormones auxin and ethylene.Arabidopsis flower abscission is inhibited, for example in the ethylene-insensitive mutants ethylene resistant 1-1 and ethylene insensitive 2. In tomato too, organ abscission is inhibited in ethylene receptor and ethylene sensitivity mutants including EIN , Never ripe , Sletr1-1, and Sletr1-2. Auxin plays a critical role in controlling abscission. The consensus of many studies is that the continuous polar flow of auxin passing through the abscission zone inhibits abscission and that reduction of this flow initiates abscission by making the AZ sensitive to ethylene. The polar flow is thought to be a reflection of agradient in auxin concentration across the abscission zone. In a series of classic experiments, it was shown that application of indole-3-acetic acid , to the distal side of Phaseolus vulgaris leaf explants inhibited abscission, while an application to the proximal side accelerated the process. The nature of the auxin gradient continues to be the subject of discussion—researchers have proposed that the gradient might be in auxin concentration, auxin biosynthesis, auxin transport, and/or auxin response. In Arabidopsis, manipulation of auxin biosynthesis specifically within floral organ AZ demonstrates that reduction of auxin level makes the flower organ shed prematurely. However, the disruption of auxin signaling/ response in AZ delayed the shedding of floral organs, suggesting that a functional IAA signaling/response pathway in AZ cells is required for abscission initiation. Given the importance of auxin balance between the distal and proximal sides of the AZ for organ shedding, it is essential to understand how this auxin gradient is maintained for regulating the initiation of the abscission process in response to developmental and environmental cues.

The energy savings produced could be used to assign an economic value to the micro-climate regulating services provided by the green space. Animal-mediated pollination is an important ecological process that supports many benefits . For example, bee pollination can increase agricultural crop quantity, food quality, and market value . However, bee populations have been declining due to pollution, higher pathogen prevalence, and lower genetic diversity . Additionally, development and urbanization cause habitat fragmentation which can lead to changes in species and functional diversity .Pollinators, such as bees and birds, can connect these habitat patches as they move along plants to feed and collect pollen . Increased suitable habitat and connectivity may facilitate the recovery of pollinator populations and create more resilient communities that can recover from disturbances, e.g. disease or long periods of intense drought . Habitat patches have been shown to maintain distinct bee communities that, in aggregate, retain a significant amount of local species diversity . The value of pollination services is typically associated with increases in agricultural productivity ,vertical grow rack but has also been evaluated in urban settings. Breeze et al. estimated WTP for non-market pollination services in the United Kingdom using a discrete choice experiment. Their estimates suggest taxpayers are willing to pay 13.4£ annually per person to maintain these benefits.

Visual indicators for potential pollination services include the presence of animal-pollinators as well as flowering plants. Quantification of this service requires data on the frequency of animal-to-flower visits as well as connectivity among NTS and other areas.NTS can have built-in, public spaces that human communities can utilize. Walking trails, bike lanes, benches, and wildlife viewing sites can provide recreational services . Urban green spaces have been linked to improvements in physical and mental health . They have also been linked to more active and healthy lifestyles overall . In Los Angeles County, which has the third highest population density in California , these types of spaces can be important in the midst of a denselypopulated and highly-urban area. The travel cost method is most often used to calculate the value of recreational services, but it may not be appropriate for hyper-local neighborhood amenities because of little-to-no cost associated with access . Contingent valuation and hedonic pricing have also been employed . The latter alludes to an equity question regarding who is paying for these spaces and who is benefitting from them. In Porto, Portugal, Graça et al. found that lower socioeconomic areas have the most green space but they are unlikely to be developed in ways that provide services to the community. This suggests that recreational services provided by green spaces can be a luxury.NTS present an opportunity for education and public outreach regarding storm water issues, pollution, watershed and urban ecology, urban planning and management, and climate change. For example, Ocean View Growing Grounds is a community garden within a food desert in inland San Diego.

OVGG incorporates bioswales into its landscape, meant to prevent crops from flooding. UC San Diego researchers have partnered with community leaders to host outreach events about hydrology, soil, and urban ecology. Greater understanding and awareness of NTS and the services they provide may lead to safer gardening practices and more efficient water use. In Los Angeles, many of the sites have educational information posted about the project, their goals, and their motivations . As part of the Elmer Avenue Green Street project, local residents participated in the planning and design processes, actively engaging in storm water issues and how to address them. Scientific research on storm water issues have proven useful, especially in developing countries where water quality is often a main concern but resources and infrastructure for large treatment plants are lacking .NTS can introduce undesired services, such as installation of unattractive elements, accumulation of pollutants, and proliferation of disease vectors. The aesthetics of NTS may not be favorable to all people, especially when they are not regularly maintained. Southern California receives very little precipitation which can be fatal for plants that are not drought resistant. Additionally, plant communities in NTS by the ocean have an added stressor of salt . This may highlight the need for use of native vegetation in NTS in order to facilitate their survival. Whether or not they are also the most aesthetically-pleasing is subjective. Regular maintenance can, not only help plant survival, but also prevent build-up of debris and pollutants, which NTS are designed to intercept. Debris degrades aesthetic value but other pollutants can cause environmental damage. Heavy metals can leach into surrounding soil and groundwater . Ponding areas, that allow microbial communities to remove contaminants, can also provide habitat for mosquitoes which pose health hazards in the form of infectious diseases and allergies.

For example, two Los Angeles NTS sites had advisories about West Nile virus and its carriers. Vegetation and soil media can also provide habitat for urban pests, such as rodents and ticks . Increases in urban green space have been linked to decreases in violent crime , but may also provide spaces in which crime can happen, e.g. assault or vandalism. Several accounts of assault were cited in the South Los Angeles Wetland Park . Almost all of these issues can be avoided at some cost whether it is increased maintenance, more frequent monitoring, or a greater police presence. The main warning here is not that these costs are usually prohibitively expensive, but that they need to be considered when planning. In summary, NTS that rely on natural structures and functions, e.g. bio-retention systems and treatment wetlands, provide built ecosystems that can support a host of targeted and non-targeted benefits . While there are few data on the quantification of these benefits in NTS specifically, we can draw on examples from relevant systems to get an idea of how these processes may work and on what scale. There also exist many economic valuation techniques that can be employed to assign a value to these ecosystem services for incorporation into urban design and management. Cost is a component of NTS in which urban planners are likely interested. Total costs consist of planning and design, permitting, raw materials, installation, maintenance, and monitoring. Most NTS are implemented in order to meet water quality regulations and, although expensive, they may be cheaper than alternative approaches. Additionally, continued use of NTS may be a sign that their co-benefits can be significant. Long term monitoring is necessary in order to assess whether the benefits discussed in here truly exist.There are two distinct objectives that need to be addressed in order to assess ecosystem services associated with NTS: the first is to determine the quantity or rate at which the ecosystem service is provided ,vertical planting tower and the second is to determine the economic value of that quantity or rate. Targeted water services have been well-documented in laboratory settings but in situ, mesocosm studies are much fewer. Similarly, although non-targeted ecosystem services are acknowledged , quantitative field studies are only just beginning to emerge. Researchers from the University of California are currently working on an interdisciplinary project that assesses the form and function of urban storm water infrastructure in southern California, including potential ecosystem services . In the following section, we discuss three potential models for ecosystem services assessment in NTS: benefit transfer approaches, stochastic frontier analysis, and data envelopment analysis. Benefit transfer approaches can be used to assign physical and economic values to ecosystem services for cost-benefit analysis. The latter two approaches, represented by production frontier models, can assess how efficiently an NTS is providing ecosystem services which may be a useful assessment tool for environmental decision-makers. Although there are few data currently, these models can be used as a starting point and improved upon as more data become available.Meta-analyses provide a database on which a regression model can be built, determining the relationship between a dependent variable and multiple explanatory variables. Meta-analyses are a method of synthesizing results from multiple studies on similar topics . They are often utilized when many studies exist and interpretation of their results is difficult, and so synthesis of results can be a helpful tool . Meta-analyses can also be useful in contrasting situations in which very few studies exist for the target system but fall within the range of systems that have been studied. For example, a keyword search of “urban carbon” in the Environmental Valuation Reference Inventory yields 76 records but only 6 studies are specific to urban green space . Regression models can then be built upon the information collected during meta analyses. In the example case of ecosystem services associated with NTS, three categories of independent variables may be relevant: the biophysical and the socio-economic characteristics of the study site, and the study characteristics.

Examples of potential explanatory variables include study site size, geographic location, scale of the study , gross domestic product per capita, valuation method, and sample size. Benefit transfer approaches use regression models to provide an estimate of the dependent variable . In addition to benefit transfer based on a function estimated from a meta-analysis, a unit value or a function estimated from one study can also be used. However, the meta-analysis approach described here is preferable because it can account for differences between the policy and study sites. The “policy site” is the site of interest and “study sites” are those from which values have been transferred. The best benefit transfer estimate will be that between policy and study sites that are identical in terms of biophysical and socio-economic characteristics. However, there are generally discrepancies among commodities, currencies, user attributes, wealth measures, and cultural differences between policy and study sites that can lead to errors . Although primary studies are ideal, they are not always feasible, given the high cost of resources and time. It is useful for government agencies to sponsor studies across NTS that provide different quantities of ecosystem services and try to value that output in a way that is likely to be more accurate for a local context.Cost-benefit analysis, a widely-used tool for decision-making, compares the economic costs and benefits of one or more decisions . If the costs outweigh the benefits, then rational actors do not partake in the action, and vice-versa. However, there are additional factors that make decisions more complicated, such as the long- versus short-term, discounting, and positive and negative externalities. Cost-benefit analysis is often used in environmental decision-making but ecosystem services are often only included qualitatively because quantitative data do not exist . The use of benefit transfer approaches can help this process by taking a first-step towards economic valuation of ecosystem services.The SFA approach is a parametric economic modelling technique that allows for random shocks, or unpredicted events, within the model. The stochastic error term may make it suitable for urban systems that are subject to environmental variation, e.g. drought, precipitation events. SFA requires a priori assumptions regarding the production function form, i.e. the mathematical relationship between inputs and outputs , and the distribution of the unobserved technical inefficiency terms, which can substantially influence results. A considerable econometric literature has been developed to help determine the adequacy of the statistical fit of a particular model. The SFA approach provides a natural measure of how inefficient a particular NTS is at providing an ecosystem service relative to other NTS configurations. DEA is a nonparametric approach that does not allow for random shocks but it does not require prior knowledge of the production function form, which makes it useful for NTS-associated ecosystem services. DEA combines inputs and outputs into one efficiency score that can be easily compared, but it requires an additional regression model to identify the impacts of independent variables. Both DEA and SFA are capable of handling multiple outputs but in SFA, they must be collapsed into one basket of outputs whose weights can have a significant impact on results. One way to weight outputs is by their economic values. However, economic values for most ecosystem services associated with NTS have not been assigned, i.e. why benefit transfer approaches may be helpful. The lack of standardized monitoring data may make a nonparametric DEA approach more feasible at this time, in addition to the SFA requirement to specify a production function form. DEA also better handles multiple outputs relative to SFA and undesirable outputs, such as negative externalities .