Quantification of the effects of architectural traits on dry mass production and light interception of tomato canopy under different temperature regimes using a dynamic functional-structural plant model

There is increasing interest in evaluating the environmental effects on crop architectural traits and yield improvement. However, crop models describing the dynamic changes in canopy structure with environmental conditions and the complex interactions between canopy structure, light interception, and dry mass production are only gradually emerging. Using tomato (Solanum lycopersicum L.) as a model crop, a dynamic functional-structural plant model (FSPM) was constructed, parameterized, and evaluated to analyse the effects of temperature on architectural traits, which strongly influence canopy light interception and shoot dry mass. The FSPM predicted the organ growth, organ size, and shoot dry mass over time with high accuracy (>85%). Analyses of this FSPM showed that, in comparison with the reference canopy, shoot dry mass may be affected by leaf angle by as much as 20%, leaf curvature by up to 7%, the leaf length: width ratio by up to 5%, internode length by up to 9%, and curvature ratios and leaf arrangement by up to 6%. Tomato canopies at low temperature had higher canopy density and were more clumped due to higher leaf area and shorter internodes. Interestingly, dry mass production and light interception of the clumped canopy were more sensitive to changes in architectural traits. The complex interactions between architectural traits, canopy light interception, dry mass production, and environmental conditions can be studied by the dynamic FSPM, which may serve as a tool for designing a canopy structure which is 'ideal' in a given environment.DFGDF

The use of lupine seeds as nitrogen fertilizer

We studied the use of lupine seeds as fertilizer to provide a slow release N source. The main objective was to compare different strategies to apply lupine seeds (Lupinus angustifolius L. cv. Azuro and cv. Boruta) as N-fertilizers for a white cabbage crop (Brassica oleracea capitata L. cv. Impuls). Since during the germination process the seedlings use storage carbohydrates as an energy source by respiration, the amount of carbon in the plant and hence the C:N ratio decreases with time. With leaf expansion and the onset of photosynthesis the flow of carbon will invert Thus the main hypothesis of this research was that incorporating germinated lupine seeds after a certain time of growth (when the C:N ratio reached its minimum value) could increase the N release of this plant-derived fertilizer. The incorporation of lupine seeds with a short germination period of 12 days increased the N released from this plant-derived fertilizer. However, N release and cabbage yield were similar in this treatment and when shredded lupine seeds were used, which represent a more practical fertilizing method. The use of shredded does not imply soil tillage needed to prepare the seed bed, sowing, and incorporating of seedling

Environmental and cultivar variability in composition, content and biological activity of phenolic acids and alkylresorcinols of winter wheat grains from a multi-site field trial across Europe

Different factors such as the genotype, environmental conditions, temperature stress, solar radiation and others can influence the phytochemical status of plants. The concentration of phenolic acids and alkylresorciols (ARs) as well as their chemical composition and biological activity have been determined in twelve winter wheat cultivars grown at eight European locations. This was the first winter wheat multi-location field trial of the European Consortium for Open Field Experimentation (ECOFE). Extracts from grain were analyzed using a UPLC-PDA-ESI-MS system (phenolic acids), UPLC-PDA-MS/MS (alkylresorcinols) and TLC-DPPH center dot test with ImageJ program (antiradical activity). The phenolic acid profile consisted of five hydroxybenzoic acid and four hydroxycinnamic acid derivatives, among which ferulic and sinapic acids were predominated. The ARs profile consisted of nine AR derivatives, among which 5-n-heneicosylresorcinol (C21:0) and 5-n-nonadecanylresorcinol (C19:0) were predominated. Our study showed significant differences in phenolic acids and AR content between wheat cultivars, as well as between locations. We observed a positive correlation between the biological activity of extracts and the total amount of phenolic acids and ARs. Two cultivars, Chambo and Julius (average of all sites) and samples from the Spanish site (average of all cultivars) showed the highest content and composition of nutritional substances

A Modeling Approach to Quantify the Effects of Stomatal Behavior and Mesophyll Conductance on Leaf Water Use Efficiency

Water use efficiency (WUE) is considered as a determinant of yield under stress and a component of crop drought resistance. Stomatal behavior regulates both transpiration rate and net assimilation and has been suggested to be crucial for improving crop WUE. In this work, a dynamic model was used to examine the impact of dynamic properties of stomata on WUE. The model includes sub-models of stomatal conductance dynamics, solute accumulation in the mesophyll, mesophyll water content, and water flow to the mesophyll. Using the instantaneous value of stomatal conductance, photosynthesis, and transpiration rate were simulated using a biochemical model and Penman-Monteith equation, respectively. The model was parameterized for a cucumber leaf and model outputs were evaluated using climatic data. Our simulations revealed that WUE was higher on a cloudy than a sunny day. Fast stomata' reaction to light decreased WUE during the period of increasing light (e.g., in the morning) by up to 10.2% and increased WUE during the period of decreasing light (afternoon) by up to 6.25%. Sensitivity of daily WUE to stomata' parameters and mesophyll conductance to 002 was tested for sunny and cloudy days. Increasing mesophyll conductance to CO2 was more likely to increase WUE for all climatic conditions (up to 5.5% on the sunny day) than modifications of stomatal reaction speed to light and maximum stomatal conductance

O uso da semente de tremoço como fertilizante azotado The use of lupine seeds as nitrogen fertilizer

Neste trabalho, estudou-se o uso de sementes de tremoço como fertilizante para fornecer gradualmente o azoto. O principal objectivo foi comparar diferentes estratégias de aplicação das sementes de tremoço (Lupinus angustifolius L. cv. Azuro e cv. Boruta) na cultura de couve-branca (Brassica oleracea capitata L. cv. Impuls). Uma vez que durante o processo de germinação as plântulas utilizam os seus glúcidos de reserva como fonte de energia na respiração, a quantidade de carbono nas plântulas e consequentemente a sua razão C:N decresce ao longo do tempo. Com a expansão das folhas e o começo da actividade fotossintética esta tendência inverte-se. Assim, a principal hipótese desta pesquisa foi que a incorporação de plântulas de tremoço germinadas após um determinado período de tempo (quando a razão C:N atingia o seu valor mínimo) pode aumentar a libertação de azoto deste fertilizante azotado de origem vegetal. Com esta pesquisa, descobriu-se que a incorporação de plântulas de tremoço após 12 dias de germinação pode aumentar a libertação de azoto. Comparando o referido método de fertilização com a incorporação de sementes de tremoço trituradas, concluiu-se também que uma vez que não levaram a diferenças entre as libertações de azoto nem entre a produção de couve-branca, a incorporação de sementes de tremoço trituradas deverá ser um método de fertilização mais prático, uma vez que este método não implica os trabalhos de mobilização do solo necessários para a preparação da cama da semente, sementeira e incorporação das plântulas de tremoço.<br>We studied the use of lupine seeds as fertilizer to provide a slow release N source. The main objective was to compare different strategies to apply lupine seeds (Lupinus angustifolius L. cv. Azuro and cv. Boruta) as N-fertilizers for a white cabbage crop (Brassica oleracea capitata L. cv. Impuls). Since during the germination process the seedlings use storage carbohydrates as an energy source by respiration, the amount of carbon in the plant and hence the C:N ratio decreases with time. With leaf expansion and the onset of photosynthesis the flow of carbon will invert. Thus the main hypothesis of this research was that incorporating germinated lupine seeds after a certain time of growth (when the C:N ratio reached its minimum value) could increase the N release of this plant-derived fertilizer. The incorporation of lupine seeds with a short germination period of 12 days increased the N released from this plant-derived fertilizer. However, N release and cabbage yield were similar in this treatment and when shredded lupine seeds were used, which represent a more practical fertilizing method. The use of shredded does not imply soil tillage needed to prepare the seed bed, sowing, and incorporating of seedlings