H2O2 as attenuator of salt stress on the physiology and growth of hydroponic cherry tomato

-In arid and semi-arid regions, agricultural production is challenging due to the scarcity of water for irrigation, so brackish water is commonly used. However, the use of these waters negatively affects the growth and development of crops. In this context, it is essential to look for strategies to mitigate the effects of salt stress on plants. The objective of this study was to evaluate the effects of foliar application of H2O2 on gas exchange, photosynthetic pigments, photochemical efficiency, and growth of cherry tomato plants in hydroponic cultivation with saline nutrient solution. The experiment was carried out in a greenhouse in Pombal-PB, using a Nutrient Film Technique (NFT) hydroponic system. Treatments were distributed in a split-plot scheme, in which the levels of electrical conductivity of the nutrient solution -ECns (2.1, 2.8, 3.5, and 4.2 dS m-1) were considered the plots and the five concentrations of H2O2 (0, 12, 24, 36, and 48 mu M) were considered the subplots, with six replicates and two plants per plot. ECns from 2.1 dS m-1 reduced gas exchange, photochemical efficiency, photosynthetic pigments, relative water content, and growth of cherry tomato. H2O2 at concentrations of 36 and 48 mu M associated with saline nutrient solution of 2.1 dS m-1 stimulated plant height, growth, and chlorophyll b synthesis, respectively. Hydrogen peroxide alone did not affect gas exchange, chlorophyll fluorescence, photosynthetic pigments, and growth of cherry tomato.