Comparatively Cognizing the Physiological Responses and Cytoprotective Adaptations in Castor Bean Genotypes Grown in Lead Contaminated Soils from Chakera Village with a Long History of Wastewater Irrigation.

Despite the widespread presence of heavy metals (HMs) in contaminated soils, there is a limiting understanding of physiological and cellular adaptive mechanisms of castor bean (Ricinus communis L.) under lead (Pb) contaminated soils of Chakera having enduring history of wastewater irrigation. This gap in knowledge hinders the development of effective strategies for managing soil pollution and protecting agricultural productivity in areas exposed to wastewater irrigation. Therefore, current pot study was conducted on two castor bean genotypes (NIAB-2020 and DS-30) on Pb contaminated soils of Chakera in glasshouse for a period of 120 days. Results showed that physiological indicators decreased under stressed conditions in NIAB-2020 and DS-30, suggesting impaired plant development. Electrolyte leakage (EL) increased in stressed plants indicating damage to cell membrane due to oxidative damage. Biochemically, the levels of superoxide dismutase (SOD) and peroxidase (POD) decreased whereas catalase (CAT) and ascorbate peroxidase (APX) showed an increase in both castor bean genotypes to mitigate oxidative stress. In similar pattern, both genotypes exhibited a reduction in total soluble proteins (TSP) and total free amino acids (TFA), while conversely total soluble sugars (TSS) and total phenolic contents (TPC) increased under stress conditions. Significant correlation was observed between various physiological, biochemical, and antioxidant enzyme responses, indicating their role as stressed biomarkers on Pb contaminated soils. Overall, NIAB-2020 outperformed DS-30 in terms of physiological and biochemical adaptations, evidencing superior adaptive approach. However, future field trials are compulsory to validate the findings of the study.