Abstract:
The current investigation was performed to assess the mitigating role of externally supplemented 24-epibrassinolide (EBR) against cadmium (Cd, 100 and 200 µM) induced stress in maize plants. Cadmium toxicity decreased shoot and root lengths, pigment content, and relative water content, whereas it raised proline content in the maize plants. Cadmium stress also increased the generation of oxidative stress biomarkers like hydrogen peroxide (H2O2), lipid peroxidation (determined as malondialdehyde content, MDA) and electrolyte leakage (EL). Highest concentration (200 µM) of Cd showed a maximum enhancement in the oxidative stress biomarkers than 100 µM. The activities of enzymatic antioxidants increased markedly with the Cd stress. The activities of catalase (CAT) and superoxide dismutase (SOD) increased by 42.10% and 23.5% with 200 µM Cd and 64.21% and 54.50% with 200 µM Cd, respectively, whereas the GST activity was decreased by 13.84% with 100 µM and 28.75% with 200 µM Cd. However, EBR application restored the Cd-induced reduction in growth parameters and physio-biochemical attributes EBR supplemented plants also abated the accretion of H2O2 and MDA contents and EL. The supplementation of EBR restored the GST activity and it also helped to further enhance the activities of SOD and CAT in the Cd stressed plants. The findings suggest that external supplementation of EBR provides a protection to maize plants against Cd toxicity by modifying growth attributes, and regulating physio-biochemical characteristics and some critical antioxidants.
Keywords:
maize
,
Growth
,
Proline
,
Antioxidants
,
Cd toxicity
,
Oxidative stress biomarkers