24-epibrassinolide promotes selenium uptake in grapevine under selenium stress

Abstract

Selenium (Se) contamination in soil is restricting the growth of fruit trees. Brassinolide is an emerging plant hormone that can enhance plant resistance to abiotic stress. We thus evaluated alleviating effects of various 24-epibrassinolide (24-EBL, one of brassinolides) concentrations on Se stress and Se accumulation in grapevine. 24-EBL increased the grapevine biomass, and the concentration of 24-EBL had a quadratic polynomial regression relationship with the root and shoot biomass under Se stress. The highest increases of root and shoot biomass were attained at 1.5 mg L−1 24-EBL, increasing by 44.43% and 39.07%, respectively, compared to the control. 24-EBL also increased the photosynthetic pigment content, peroxidase (POD) activity, and superoxide dismutase (SOD) activity of grapevine. Moreover, 24-EBL increased the total Se, organic Se, and inorganic Se contents in grapevine. The concentration of 24-EBL exhibited a positive linear regression relationship with the total Se content. The highest increases of root and shoot total Se contents were attained at 2.0 mg L−1 24-EBL, increasing by 23.75% and 95.66%, respectively, compared to the control. 24-EBL promoted the organic Se transport but inhibited the inorganic Se transport from roots to shoots. Correlation, grey relational, principal component, and cluster analyses collectively revealed that the POD activity, SOD activity, and chlorophyll a content were closely associated with the shoot total Se content. Therefore, applying 24-EBL can alleviate Se stress and promote Se uptake in grapevine.