Mitigation of Cadmium Induced Oxidative Stress by Using Organic Amendments to Improve the Growth and Yield of Mash Beans [Vigna mungo (L.)]

Abstract

Cadmium (Cd) stress is a serious environmental hazard that has devastating impacts on plant growth and productivity. Moreover, the entrance of Cd into the human food chain by eating Cd-contaminated food also poses serious health issues. Organic amendments (OA) possess an excellent potential to reduce the adverse impacts of Cd stress. Therefore, the aim of this study was to determine the potential of different OA in improving the mash beans growth and yield grown under Cd-contaminated soil. The soil was spiked with different concentrations of Cd (0, 10 and 20 mg/kg) and subjected to different OA, i.e., control, cow manure (5%), sugarcane press mud (5%) and a combination of cow manure (2.5%) and sugarcane press mud (2.5%). Results indicated that Cd stress induced a significant reduction in growth and yield traits, leaf water status, photosynthetic pigments, protein accumulation and anti-oxidant activities. However, the application of OA appreciably reduced the Cd-induced toxic effects and caused a significant increase in growth and yield. The application of 5% sugarcane press mud remained the top performer and it increased the mash bean growth and yield through improved photosynthetic pigments, leaf water status (56%) and reduced Cd uptake (18%), hydrogen peroxide (H2O2) production (38.52%), electrolyte leakage (EL) (42.13%) malondialdehyde (MDA) accumulation (55.88%) and increased accumulation of soluble protein (60.15%) and free amino acids (54%) through improved activities of anti-oxidant enzymes. Therefore, these findings suggested that the application of sugarcane press mud enhanced the growth and yield through reduced Cd accumulation, enhanced photosynthetic pigments, leaf water status, protein and amino accumulation and reduced H2O2, EL and MDA accumulation through a stronger anti-oxidant defense system.