Hydrogen peroxide signal photosynthetic acclimation of Solanum lycopersicum L. cv Micro-Tom under water deficit.

The current climate change setting necessitates the development of methods to mitigate the effects of water scarcity to ensure the sustainability of agricultural activities.f Hydrogen peroxide (H 2 O 2 ) is a plant signaling molecule that can trigger metabolic defense mechanisms in response to adverse environmental circumstances like as drought. The purpose of this study was to investigate if foliar application of H 2 O 2 stimulates modifications in photosynthetic metabolism for adaptation of tomato plants to a period of water deficit and recovery. The study, which was carried out in a factorial scheme, tested plants subjected to two water conditions (well-watered plants and plants subjected to water deficit), as well as foliar application of 1 mM H 2 O 2 (zero, one, or two applications, 24 h after the first), and was evaluated in two moments, during the deficit period and after recovery. Foliar application of 1 mM H 2 O 2 resulted in a 69% increase in the maximum rate of RuBisCO carboxylation in well-watered plants, contributing to tomato photosynthetic adjustment. H 2 O 2 treatment resulted in a 37% increase in dry mass in these plants. In plants subjected to water deficiency, 2× H 2 O 2 increased stress tolerance by reducing the maximal rate of RuBisCO carboxylation by only 18%, but in plants that did not receive H 2 O 2 treatment, the reduction was 86% in comparison to the wet plants. Plants exposed to a water shortage and given 2× H 2 O 2 stored sucrose in the leaves and had a 17% higher relative water content than plants not given H 2 O 2 . Thus, H 2 O 2 foliar treatment can be used in tomato management to induce drought tolerance or to boost photosynthetic activity and dry mass formation in well-watered plants.