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sur le développement des zones arides et semi-arides

Titre : Influence of drought cycles on carbohydrates and antioxidants metabolism in tomato (Lycopersicum esculentum Mill.) wild-type and flacca mutant grown under different light regimes

Uticaj ciklusa suše na metabolizam ugljenih hidrata i antioksidanata kod divljeg tipa i flacca mutanta paradajza (Lycopersicum esculentum Mill.) gajenih na različitim svetlosnim režimima

Auteur : Živanović Bojana R.

Université de soutenance : University of Belgrade

Grade : Doctoral Disertation 2022

Résumé
Drought stress combined with high light intensity is one of the most common abiotic factors that have a negative impact on plant growth and yield. In order to examine the effect of reduced abscisic acid (ABA) level in the development strategies necessary for drought tolerance in plants, tomato genotypes with constitutively different ABA content, wild type Ailsa Craig and flacca mutant, were used in this study. Plants grown on either lower or higher light intensity were subjected to one or three drought cycles, followed by periods of rehydration. The impact of drought and rehydration was monitored on morphological (fresh and dry weight, leaf area) and physiological level (stomatal conductivity, leaf water potential), and by measuring biochemical (carbohydrates, amino acids, ascorbate) and molecular parameters (expression of genes involved in ABA metabolism and expression of noncoding RNA molecules). The results obtained in this dissertation showed that maintaining ABA homeostasis is crucial for tomato growth and development, even in optimal water regimes, and also that flacca mutant is a suitable model system for studying the impact of reduced ABA accumulation in development of drought tolerance strategies. It has been noticed that morphological changes and osmolyte accumulation in both genotypes significantly contribute in developing drought tolerance mechanisms of tomato plants. Exposure of plants to several drought cycles has induced changes in the accumulation of antioxidant components (ascorbate and epidermal flavonoids), cell wall structure, but also in the expression of non-coding RNA molecules, which could potentially contribute to memory development in tomatoes.

Mots Clés : flacca mutant, abscisic acid, drought cycles, rehydration, memory, carbohydrates, amino acids, ascorbate, cell wall, noncoding RNAs

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