Hydrogen peroxide as attenuator of salt stress effects on the physiology and biomass of yellow passion fruit

The success of yellow passion fruit cultivation in the semi-arid region of Northeast Brazil is conditioned on the ability of this crop to develop under salt stress conditions, so it is necessary to identify techniques capable of attenuating the deleterious effects caused by irrigation with high-salinity waters. In this context, the present study aimed to evaluate the fluorescence, photosynthetic pigments and biomass of yellow passion fruit cultivated under salt stress and foliar application of hydrogen peroxide. The study was conducted in a greenhouse, with the experimental design in randomized blocks with three replicates, in a 4 x 4 factorial scheme, which consisted of four values of irrigation water electrical conductivity - ECw (0.7, 1.4, 2.1 and 2.8 dS m(-1)) and four concentrations of hydrogen peroxide (0, 20, 40 and 60 mu M). Irrigation using water with ECw from 1.4 dS m(-1) compromised the photochemical efficiency, photosynthetic pigments, and biomass production of yellow passion fruit. Application of hydrogen peroxide at concentration of 20 mu M promoted the highest values for variable and maximum fluorescence and concentration of carotenoids, constituting an alternative for the acclimation of yellow passion fruit to salt stress. Application of hydrogen peroxide at concentrations above 20 mu M intensified the salt stress on passion fruit.