Peróxido de hidrogênio na atenuação do estresse salino em gravioleira

Abstract

ABSTRACT In semi-arid regions, the use of saline water for irrigation has become an increasingly frequent reality due to the qualitative and quantitative scarcity of water sources occurring most of the year. Thus, the use of hydrogen peroxide can be a strategy capable of mitigating the deleterious effects of salt stress on plants and guaranteeing the agricultural production of crops such as soursop. Thus, the objective of this study was to evaluate the effects of foliar application of hydrogen peroxide on the physiological and growth indices of soursop plants cv. Morada Nova irrigated with waters of different salinity levels. The treatments were distributed in a randomized block design, in a 4 × 4 factorial scheme, corresponding to four levels of electrical conductivity of irrigation water and four concentrations of hydrogen peroxide, with three replicates. Foliar application of hydrogen peroxide at concentrations of 12, 18 and 15 µM, respectively, attenuated the effects of salt stress on stomatal conductance, CO2 assimilation rate and chlorophyll a synthesis of soursop, at 780 days after transplanting. The 30 µM hydrogen peroxide concentration intensified salt stress on gas exchange, variable fluorescence and electrolyte leakage in the leaf blade of soursop plants cv. Morada Nova, 780 days after transplanting.