Effect of zinc application on water content and photosynthetic pigments of mungbean (Vigna radiata L.) under water stress

Abstract

A field experiment was conducted during rabi season of 2017-18 at agricultural college farm, Bapatla to investigate the effect of seed pretreatment and foliar application of zinc on relative water content (RWC) and photosynthetic pigments in mungbean under moisture stress, in a split plot design with three replications. The treatments comprised of two main treatments viz., no stress i.e. control (M0) and stress from flowering stage (i.e. from 30 DAS) up to harvest (M1) and seven sub-treatments viz., no zinc application (S0), seed treatment with 0.05% and 0.075% ZnSO4 solutions for 5 hrs before sowing (S1 and S2), foliar spray of 300, 400 and 500 ppm ZnSO4 at 30 DAS (S3, S4 and S5) and water spray at 30 DAS (S6). The results of the study revealed that plants that were subjected to water stress from flowering stage decreased the RWC, total chlorophyll and carotenoid contents by 10.0, 7.5 and 12.6 per cent, respectively, over control plants. Among zinc treatments, Zinc foliar spray @ 500 ppm at 30 DAS increased the RWC, total chlorophyll and carotenoid contents by 8.1, 10.2 and 6.1 per cent respectively, over untreated plants. It can be concluded that the use of zinc spray @ 500 ppm at 30 DAS counteracted the negative effects of water stress on mungbean by maintaining high water potential and by actively synthesizing the photosynthetic pigments.