Effects of foliar application of amino acid-chelated selenite on photosynthetic characteristics of peanut (Arachis hypogaea L.) leaves at the podding stage

Abstract

Foliar application of selenium (Se) is an effective measure to increase Se concentrations in peanut pods. However, how the foliar application of amino acid-chelated selenite affects the photosynthetic characteristics of peanut leaves at the podding stage is still unclear. Here, the effects of Se on the activities of antioxidant enzymes, the concentrations of chlorophyll, soluble protein, soluble sugar, and reduced glutathione (GSH), photosynthetic parameters, and Se concentration of peanut leaves were investigated by spraying selenite, L-lysine-chelated selenite, and amino acid-chelated selenite solutions, respectively. The results indicated that foliar application of Se could significantly increase leaf Se concentration. The net photosynthetic rate (P_n), stomatal conductance (g_s), and transpiration rate (T_r) of leaves were significantly higher than those in the control. However, peanut leaves’ intercellular CO₂ concentration (c_i) decreased significantly. Further study found that the concentrations of chlorophyll, soluble protein, soluble sugar, and GSH in peanut leaves increased significantly, and the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in peanut leaves were significantly higher than those in control. However, there were no significant differences between the foliar application of selenite, L-lysine-chelated selenite, and amino acid-chelated selenite. Thus, foliar application of selenite, L-lysine-chelated selenite, and amino acid-chelated selenite could effectively enhance the photosynthetic functions of peanut leaves, which was closely associated with the improvement of antioxidant enzyme activities and the concentrations of soluble sugar, soluble protein, and GSH, resulting in inhibiting chlorophyll degradation and improving the photosynthetic functions of peanut leaves.