Unravelling the roles of redox homeostasis and antioxidant system in facilitating adaptive responses during Pb induced hormesis in Brassica juncea

Abstract

This research explores the role of the antioxidant-prooxidant balance in eliciting the hormesis effect in Brassica juncea seedlings exposed to mild Lead (Pb). Excessive Pb doses in plants causes oxidative stress, which damages plant cells, stunts growth, and reduces agricultural yield. Conversely, mild Pb doses induce a hormetic effect inside plants system, leading to beneficial adaptive changes at cellular, molecular, and physio-biochemical levels. The plant's antioxidant defence network often relieves Pb metal stress. Antioxidants, both enzyme-based and non-enzyme-based, neutralize reactive oxygen species (ROS) created by Pb stress, protecting cellular structures and promoting plant resilience. Also, the idea of hormesis, which describes how modest doses of toxins like Pb metals cause plants to adapt, helps us understand how plants protect themselves and enhance stress tolerance to handle stress by raising antioxidant activity. In the present study, mild Pb exposed 10 days old B. juncea seedlings were tested for antioxidant activity and gene expression. Moderate Pb exposure increased B. juncea seedling protein content, antioxidant enzyme activity, and gene expression. The results suggest the possible role of antioxidants in inducing hormetic responses in B. juncea seedlings exposed to Pb, laying the foundation for understanding how these mechanisms cooperate to minimize Pb impact and improve seedling resilience.