Guidelines to use tomato in experiments with a controlled environment

Domesticated tomato (Solanum lycopersicum) is the most important horticultural crop worldwide. Low polymorphism at the DNA level conflicts with the wealth of morphological variation. Fruits vary widely in size, shape, and color. In contrast, genetic variation between the 16 wild relatives is tremendous. Several large seed banks provide tomato germplasm for both domesticated and wild accessions of tomato. Recently, the genomes of the inbred cultivar “Heinz 1706” (≈900 Mb), and S. pimpinellifolium (739 Mb) were sequenced. Genomic markers and genome re-sequencing data are available for >150 cultivars and accessions. Transformation of tomato is relatively easy and T-DNA insertion line collections are available. Tomato is widely used as a model crop for fruit development but also for diverse physiological, cellular, biochemical, molecular, and genetic studies. It can be easily grown in greenhouses or growth chambers. Plants grow, flower, and develop fruits well at daily light lengths between 8 and 16 h. The required daily light integral of an experiment depends on growth stage and temperature investigated. Temperature must be 10–35°C, relative humidity 30–90%, and, CO2 concentration 200–1500 μmol mol−1. Temperature determines the speed of the phenological development while daily light integral and CO2 concentration affect photosynthesis and biomass production. Seed to seed cultivation takes 100 days at 20°C and can be shortened or delayed by temperature. Tomato may be cultivated in soil, substrates, or aeroponically without any substrate. Root volume, and water uptake requirements are primarily determined by transpiration demands of the plants. Many nutrient supply recipes and strategies are available to ensure sufficient supply as well as specific nutrient deficits/surplus. Using appropriate cultivation techniques makes tomato a convenient model plant for researchers, even for beginners

Effects of environmental factors on carotenoid content in tomato (Lycopersicon esculentum (L.) Mill.) grown in a greenhouse

Tomatoes are an important source of lycopene in the human diet. The effect of temperature (15°C - 24°C), CO2 supply (380 - 1000 ppm) and nutrient concentration measured as electrical conductivity of the nutrient solution (EC, 2 - 9 dS m-1) on the content of carotenoids (lycopene, ß-carotene) were investigated in two tomato cultivars grown in a greenhouse. The cherry tomato cultivar Supersweet was characterised by higher lycopene contents than the conventional round tomato ‘Counter’. The results indicated that temperature has a significant influence on the biosynthesis of lycopene and ß-carotene during ripening. A temperature above 20°C seems to be optimal for lycopene production in the investigated cultivars, whereas a decrease to 15°C diminished the lycopene content. Neither CO2 supply nor EC increase affected the carotenoid content under the conditions investigated

Antifogging additives for greenhouse covers - effects on phytochemicals and nutritional quality of lettuce

Antifogging additives are commercially used in greenhouse films to prevent water droplet formation on these films. This can increase light transmission, and thus, improve crop yield. However, the effect of polytunnels with antifogging additives on phytochemical content in lettuce (Lactuca sativa var. capitata ) is currently unclear. Here, polytunnels were chosen as a model to investigate the impact of antifogging additives in a completely randomized setting. Analysis by means of chromatographic methods coupled with mass spectrometry revealed a general influence of polytunnel cultivation compared to lettuces grown without a polytunnel on the content of phenolic compounds, photosynthetic pigments and fatty acids. The use of antifogging additives does not lead to significant differences in phenolic compounds and fatty acids. However, significant differences were observed for carotenoids and chlorophylls by both polytunnel cultivation and the use of antifogging additives. These differences probably occurred predominantly due to differences in light and temperature regimes related to polytunnel cultivation. Thus, due to polytunnels in general and the use of antifogging additives in particular, environmental conditions are created that impact valuable compounds and alter nutritional quality of crops

Variation of morphological descriptors for the evaluation of tomato germplasm and their stability across different growing conditions

[EN] Germplasm and breeding materials are usually characterized using morphological and agronomic descriptors, which should have a high heritability. Despite the widespread use of tomato (Solanum lycopersicum) standardized descriptors, little information exists on environmental effects on descriptor values and their heritability. We have evaluated 12 tomato accessions from seven cultivar groups in three different environments (open-field conventional, open-field organic, and greenhouse) and characterized them with 36 descriptors. A wide range of variation was found for most descriptors, demonstrating their utility for describing tomato materials and their diversity and relationships. The analysis of descriptors variation reveals that while for some descriptors with a simple genetic control the accession effect accounts for 100% of the variation, for others like yield per plant only 10.83% of the variation observed is due to the accession effect. Although significant differences were found among environments for most descriptors, including a much higher yield in the open-field conventional environment than in the two others, the environmental effect was low for most traits. However, the genotype×environment effect generally had an important contribution to the structure of variation for many descriptors, and for three traits it had the highest contribution to the percentage of the sum of squares. As a result of the variation structure, the heritability values are high (> 0.7) for only 10 descriptors, while for five is low (< 0.3). Principal components analysis (PCA) reveals that projections in the PCA graph of a same accession grown in different environments plot together in the same area of the PCA graph. Although cultivar groups are generally clearly separated in the PCA graph, accessions from the same cultivar group in some cases are intermixed. These results have important implications for detecting tomato duplicates and establishing core collections, as well as for analyzing germplasm and breeding results, when using data sets containing data of accessions grown in different environments.This work has been partially funded by the TRADITOM (Traditional tomato varieties and cultural practices: a case for agricultural diversification with impacto n food security and health of European population) and G2P-SOL (Linking genetic resources, genomes and phenotypes of Solanaceous crops) projects. These projects have received funding from the European Union's Horizon 2020 research and innovation programme under grant agreements No 634561 (TRADITOM) and No 677379 (G2P-SOL). Authors are grateful to Mr. Jonatan Cerdan for his technical help.Figás-Moreno, MDR.; Prohens Tomás, J.; Casanova-Calancha, C.; Fernández De Córdova Martínez, PJ.; Soler Aleixandre, S. (2018). Variation of morphological descriptors for the evaluation of tomato germplasm and their stability across different growing conditions. Scientia Horticulturae. 238:107-115. https://doi.org/10.1016/j.scienta.2018.04.039S10711523

Plasma Polyamine Levels in Patients with Liver Insufficiency

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Light-Mediated Reduction in Photosynthesis in Closed Greenhouses Can Be Compensated for by CO2 Enrichment in Tomato Production

Concepts of semi-closed greenhouses can be used to save energy, whereas their technical equipment often causes a decrease in the light received by the plants. Nevertheless, higher yields are achieved, which are presumably triggered by a higher CO2 concentration in the greenhouse and associated higher photosynthesis because of the technical cooling and the longer period of closed ventilation. Therefore, we examined the effects of photosynthetic photon flux density (PPFD) and CO2 concentration on plant photosynthesis and transpiration in tomato using a multiple cuvette gas exchange system. In a growth chamber experiment, we demonstrated that a light-mediated reduction in photosynthesis can be compensated or even overcompensated for by rising CO2 concentration. Increasing the CO2 concentration from 400 to 1000 µmol mol−1 within the PPFD range from 303 to 653 µmol m−2 s−1 resulted in an increase in net photosynthesis of 51%, a decrease in transpiration of 5 to 8%, and an increase in photosynthetic water use efficiency of 60%. Estimations showed that light reductions of 10% can be compensated for via increasing the CO2 concentration by about 100 µmol mol−1 and overcompensated for by about 40% if CO2 concentration is kept at 1000 instead of 400 µmol mol−1.Peer Reviewe

Strategies to control water and nutrient supplies to greenhouse crops. A review

This paper introduces the approaches to automatic control of water and nutrient supplies to greenhouse crops. The traditional concepts of surplus irrigation and fertilization conflict with the environmental aspect. Therefore, water and nutrient demands of the plants must be met by the supplies. The generally used strategy is based on the application of standard nutrient solutions and frequent analyses of the nutrient solution concentration in the root environment. An improvement to this strategy is expected by using a feedback control, which takes ion sensitive measurements of the drainage water concentration or a feedforward control, where nutrient and water uptake are predicted using growth and transpiration models. Most of these approaches are still on a theoretical level and are far from being practical applications. Current strategies are directed towards the synchronization of uptake and supply, but future strategies should control plant functioning.Mise au point : stratégies pour contrôler les apports d'eau et d'éléments nutritifs aux cultures sous serre. Cet article introduit les approches pour un contrôle automatique des alimentations en eau et en éléments nutritifs pour les cultures sous serre. Le concept traditionnel d'irrigation et de fertilisation excédentaires entre en conflit avec les aspects environnementaux. Cependant, les demandes d'eau et d'éléments nutritifs des plantes doivent être satisfaits par les apports. La stratégie utilisée généralement est basée sur l'emploi de solutions nutritives standard et de fréquentes analyses de la concentration de la solution nutritive dans l'environnement des racines. Une amélioration de cette stratégie est espérée en utilisant un système de rétroaction, qui prend en compte des mesures sensibles de la concentration ionique de l'eau de drainage, ou un système de réaction anticipée dans lequel les besoins en eau en éléments nutritifs sont prévus à parti de modèles de croissance et de transpiration. Ces approches sont pour la plupart d'entre elles, développées sur un plant théorique et sont encore loin des applications pratiques. Les stratégies actuelles sont dirigées vers la synchronisation des prélèvements et des apports, mais les stratégies futures devront contrôler le fonctionnement des plantes