Do soilless culture systems have an influence on product quality of vegetables?

In the horticulture industry, the focus has traditionally been on yield. However, consumers’ interest worldwide in the quality of horticultural products has increased in the recent past and will become the driving force in the future. Soilless culture systems (SCSs), the most intensive production method in today’s horticulture industry, are based on environmentally friendly technology, which can result in higher yields, even in areas with adverse growing conditions. However, using SCSs does not automatically result in the production of high-quality vegetables. Numerous studies confirm that a SCS enables growers to produce vegetables without quality losses compared to soil cultivation. An adaptation of cultural management to the specific cultural system, as well as crop demand, can further result in the improvement of the quality of horticultural products

Influence of heat shock pretreatment on growth and development of tomatoes under controlled heat stress conditions

The effect of a previous heat shock (HS) on growth and development of different tomato (Lycopersicon esculentum Mill.) cultivars under defined heat stress (HSt) conditions were investigated. Plants were grown under two day/night temperature regimes (26/20 ºC and 37/27 ºC, respectively) in growth chambers at the Department of Vegetable Crops, Institute for Horticultural Sciences, Faculty of Agriculture and Horticulture, Humboldt University of Berlin. The experiments were conducted twice and were set up in a randomized design with five replicates. The reproductive processes in tomato were more sensitive to high temperatures than the vegetative ones. The number of pollen grains, number of fruits and fruit fresh masses produced by the heat tolerant cultivars were higher than those of the heat sensitive cultivars. However, HS pretreatments had no positive effects on tomato growth and development

Hormonal changes, growth and yield of tomato plants in response to chemical and bio-fertilization application in sandy soils

The response of tomato plants to chemical and bio-fertilization under sandy soil conditions was investigated. The experiments were conducted in Nubaria region, Egypt. Tomato plants were treated with Microbein or a mixture of Phosphorine and Biogein as bio-fertilizers under different rates of the recommended nitrogen and phosphorus fertilization (100% of N and P, 75% of N and P and 50% of N and P). In addition, plants of three treatments received only the rates of chemical fertilizers and were not treated with the bio-fertilizers. Vegetative growth measurements, yield, hormonal changes in leaves, and N, P and K contents of leaves were recorded to study the effects of these treatments. The results showed that bio-fertilization significantly increased the vegetative growth of tomato plants (including plant height, number of branches, number of leaves and the fresh weight of plants) and yield compared to non-treated plants. Growth and yield of tomato plants was negatively affected by the low chemical fertilization treatments especially at 50% of N and P while biofertilization enhanced growth and productivity under such conditions. Tomato plants which were treated with a mixture of Phosphorine and Biogein had higher growth and yield than plants treated with Microbein. Bio-fertilization resulted in higher N, P and K contents of leaves and higher indole acetic acid (IAA), Gibberellins (GA3) and Cytokinins. The possible effects of the treatments are discussed

Strategies for improved yield and water use efficiency of lettuce (Lactuca sativa L.) through simplified soilless cultivation under semi-arid climate

Simplified soilless cultivation (SSC) systems have globally spread as growing solutions for low fertility soil regions, low availability of water irrigation, small areas and polluted environments. In the present study, four independent experiments were conducted for assessing the applicability of SSC in the northeast of Brazil (NE-Brazil) and the central dry zone of Myanmar (CDZ-Myanmar). In the first two experiments, the potentiality for lettuce crop production and water use efficiency (WUE) in an SSC system compared to traditional on-soil cultivation was addressed. Then, the definition of how main crop features (cultivar, nutrient solution concentration, system orientation and crop position) within the SSC system affect productivity was evidenced. The adoption of SSC improved yield (+35% and +72%, in NE-Brazil and CDZ-Myanmar) and WUE (7.7 and 2.7 times higher, in NE-Brazil and CDZ-Myanmar) as compared to traditional on-soil cultivation. In NE-Brazil, an eastern orientation of the system enabled achievement of higher yield for some selected lettuce cultivars. Furthermore, in both the considered contexts, a lower concentration of the nutrient solution (1.2 vs. 1.8 dS m−1) and an upper plant position within the SSC system enabled achievement of higher yield and WUE. The experiments validate the applicability of SSC technologies for lettuce cultivation in tropical areas

Tomato yield, physiological response, water and nitrogen use efficiency under deficit and partial root zone drying irrigation in an arid region

Water scarcity in arid regions is a serious problem, which calls for innovative irrigation water management. Partial root zone drying (PRD) technique can considerably reduce irrigation amount for crops. To investigate this further, tomato plants were imposed to either surface drip (SUR) with full irrigation (FI) at 100% of evaporative demands and regulate deficit irrigation (RDI) at 50% water of FI or subsurface drip irrigation (SDI) with fixed PRD at 75 (PRD75) and 50% (PRD50) of the FI. Surface evaporation under SUR with FI constitutes a large fraction of water losses from cropped fields while SDI with PRD75 preserved more water for plant uptake. Plants grown under water saving treatments showed lower stomatal conductance and transpiration rates compared to FI plants. Tomato yield under SDI with PRD75 was comparable to yield under SUR with FI for both tested seasons along with 25% water saving and 30% increase in water use efficiency (WUE). Otherwise, PRD50 reduced yield by 18-20%, but a substantial amount of irrigation water was saved along a 60 and 65% higher WUE compared to FI treatment. Fruit dry weight and harvest index (HI) were significantly higher with PRD75 compared to the other treatments. Seasonal N uptake and in turn N recovery was higher in PRD75 than any other treatment associated with improving N use efficiency

Rhesus macaque MHC class I molecules show differential subcellular localizations

The MHC class I gene family of rhesus macaques is characterised by considerable gene duplications. While a HLA-C-orthologous gene is absent, the Mamu-A and in particular the Mamu-B genes have expanded, giving rise to plastic haplotypes with differential gene content. Although some of the rhesus macaque MHC class I genes are known to be associated with susceptibility/resistance to infectious diseases, the functional significance of duplicated Mamu-A and Mamu-B genes and the expression pattern of their encoded proteins are largely unknown. Here, we present data of the subcellular localization of AcGFP-tagged Mamu-A and Mamu-B molecules. We found strong cell surface and low intracellular expression for Mamu-A1, Mamu-A2 and Mamu-A3-encoded molecules as well as for Mamu-B*01704, Mamu-B*02101, Mamu-B*04801, Mamu-B*06002 and Mamu-B*13401. In contrast, weak cell surface and strong intracellular expression was seen for Mamu-A4*1403, Mamu-B*01202, Mamu-B*02804, Mamu-B*03002, Mamu-B*05704, Mamu-I*010201 and Mamu-I*0121. The different expression patterns were assigned to the antigen-binding α1 and α2 domains, suggesting failure of peptide binding is responsible for retaining ‘intracellular’ Mamu class I molecules in the endoplasmic reticulum. These findings indicate a diverse functional role of the duplicated rhesus macaque MHC class I genes

Human NK Cells Differ More in Their KIR2DL1-Dependent Thresholds for HLA-Cw6-Mediated Inhibition than in Their Maximal Killing Capacity

In this study we have addressed the question of how activation and inhibition of human NK cells is regulated by the expression level of MHC class I protein on target cells. Using target cell transfectants sorted to stably express different levels of the MHC class I protein HLA-Cw6, we show that induction of degranulation and that of IFN-γ secretion are not correlated. In contrast, the inhibition of these two processes by MHC class-I occurs at the same level of class I MHC protein. Primary human NK cell clones were found to differ in the amount of target MHC class I protein required for their inhibition, rather than in their maximum killing capacity. Importantly, we show that KIR2DL1 expression determines the thresholds (in terms of MHC I protein levels) required for NK cell inhibition, while the expression of other receptors such as LIR1 is less important. Furthermore, using mathematical models to explore the dynamics of target cell killing, we found that the observed delay in target cell killing is exhibited by a model in which NK cells require some activation or priming, such that each cell can lyse a target cell only after being activated by a first encounter with the same or a different target cell, but not by models which lack this feature

ATHENA: A knowledge-based hybrid backpropagation-grammatical evolution neural network algorithm for discovering epistasis among quantitative trait Loci

<p>Abstract</p> <p>Background</p> <p>Growing interest and burgeoning technology for discovering genetic mechanisms that influence disease processes have ushered in a flood of genetic association studies over the last decade, yet little heritability in highly studied complex traits has been explained by genetic variation. Non-additive gene-gene interactions, which are not often explored, are thought to be one source of this "missing" heritability.</p> <p>Methods</p> <p>Stochastic methods employing evolutionary algorithms have demonstrated promise in being able to detect and model gene-gene and gene-environment interactions that influence human traits. Here we demonstrate modifications to a neural network algorithm in ATHENA (the Analysis Tool for Heritable and Environmental Network Associations) resulting in clear performance improvements for discovering gene-gene interactions that influence human traits. We employed an alternative tree-based crossover, backpropagation for locally fitting neural network weights, and incorporation of domain knowledge obtainable from publicly accessible biological databases for initializing the search for gene-gene interactions. We tested these modifications <it>in silico </it>using simulated datasets.</p> <p>Results</p> <p>We show that the alternative tree-based crossover modification resulted in a modest increase in the sensitivity of the ATHENA algorithm for discovering gene-gene interactions. The performance increase was highly statistically significant when backpropagation was used to locally fit NN weights. We also demonstrate that using domain knowledge to initialize the search for gene-gene interactions results in a large performance increase, especially when the search space is larger than the search coverage.</p> <p>Conclusions</p> <p>We show that a hybrid optimization procedure, alternative crossover strategies, and incorporation of domain knowledge from publicly available biological databases can result in marked increases in sensitivity and performance of the ATHENA algorithm for detecting and modelling gene-gene interactions that influence a complex human trait.</p

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]