Foliar application of gibberellic acid endorsed phytoextraction of copper and alleviates oxidative stress in jute (Corchorus capsularis L.) plant grown in highly copper-contaminated soil of China

Copper (Cu) is an abundant essential micronutrient element in various rocks and minerals and is required for a variety of metabolic processes in both prokaryotes and eukaryotes. However, excess Cu can disturb normal development by adversely affecting biochemical reactions and physiological processes in plants. The present study was conducted to explore the potential of gibberellic acid (GA₃) on fibrous jute (Corchorus capsularis L.) seedlings grown on Cu mining soil obtained from Hubei Province China. Exogenous application of GA₃ (10, 50, and 100 mg/L) on 60-day-old seedlings of C. capsularis which was able to grow in highly Cu-contaminated soil (2221 mg/kg) to study different morphological, physiological, and Cu uptake and accumulation in different parts of C. capsularis seedlings. According to the results, increasing concentration of GA₃ (more likely 100 mg/L) alleviates Cu toxicity in C. capsularis seedlings by increasing plant growth, biomass, photosynthetic pigments, and gaseous exchange attributes. The results also showed that exogenous application of GA₃ reduced oxidative stress in C. capsularis seedlings by the generation of extra reactive oxygen species (ROS). The reduction in oxidative stress in C. capsularis seedlings is because that plant has strong enzymatic antioxidants [superoxidase dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT)], which ultimately increased their activities to overcome oxidative damage in the cells/tissues. In addition to the plant growth, biomass, and photosynthesis, foliar application of GA₃ also helps to increase metal (Cu) concentration in different parts of the plants when compared to 0 mg/L of application of GA₃. From these findings, we can conclude that foliar application of GA₃ plays a promising role in reducing ROS generation in the plant cells/tissues and increased phytoextraction of Cu in different plant parts. However, more investigation is needed on field experiments to find a combination of GA₃ with a very higher concentration of Cu using fibrous C. capsularis.