Physiological changes of bell pepper grown under nutrient solutions prepared with brackish water and H2O2 concentrations

Abstract

The adoption of strategies to mitigate the negative effects of excess salts in irrigation water is essential for maintaining productive systems, especially in semiarid regions. The objective was to evaluate the gas exchange and chloroplast pigments of hydroponic bell pepper under combinations of water (saline and rain) and exogenous application of hydrogen peroxide (H₂O₂). The experiment was developed in a protected environment belonging to the Agricultural Engineering Academic Unit, in a completely randomized experimental design, with treatments arranged in a 4 x 3 factorial scheme, with 5 replications, consisting of the mixture between brackish water (BW) and rain water (RW): C1 = 10% BW + 90% RW; C2 = 20% BW + 80% RW; C3 = 30% BW + 70% RW; C4 = 40% BW + 60% RW) and three concentrations of hydrogen peroxide (H₂O₂) [0.0 (control); 7.5 µM and 15 µM]. The application of 15.0 μM H₂O₂ in bell pepper plants cultivated with nutrient solution in the combinations 30% SW + 70% RW and 40% BW + 60% RW between brackish water and rainwater promoted an increase in photosynthesis 24 days after the sowing while. At 61 days after sowing, the highest values of gs and E of bell pepper grown with nutritive solution in the combinations 10% BW + 90% RW were obtained with the application of 15.0 μM H₂O₂. The levels of chlorophyll “a”, “b”, total and carotenoids in bell pepper had the deleterious effects caused by the salinity of the nutrient solution mitigated by the exogenous application of hydrogen peroxide at a concentration of 15 μM.