Castasterone regulated polyphenolic metabolism and photosynthetic system in Brassica juncea plants under copper stress

Abstract

Cu is a micronutrient required for normal growth and development, but in excess amounts it became toxic. The present study investigated the effect of castasterone on regulation of polyphenolic metabolism and photosynthetic system along with effect on morphology of Brassica juncea plants under copper stress. Four concentrations of copper (0, 0.25, 0.50 and 0.75 mM) were used with or without castasterone. Copper treated plants significantly decreased the growth, biomass and photosynthetic pigments and photosynthetic characteristics. The copper toxicity also affected the total phenolic content, activity of polyphenol oxidase and caused variation in polyphenolic content. Application of castasterone significantly alleviated copper toxicity showing improvement in growth, biomass and photosynthetic systems. The activity of polyphenol oxidase and total phenolic content enhanced with castasterone supplementation, which improved the antioxidant potential of plants. These results showed that supplementation of castasterone can be useful for the enhancement of growth and biomass of plants growing in copper contaminated soils.