Stress Ameliorative Effects of Indole Acetic Acid on Hordeum vulgare L. Seedlings Subjected to Zinc Toxicity

摘要

The heavy metals present in the environment accumulate in the plants and affect their productivity and yield.By entering the food chain,metals cause several serious health problems in human beings as well as in other organisms.Indole acetic acid(IAA)is known to act as a signaling molecule between symbiotic association of metal accumulating plants and plant growth promoting rhizobacteria(PGPR).Present study demonstrated a protective role of IAA against surplus Zinc(Zn)-induced toxicity to Hordeum vulgare seedlings.Elevated Zn concentrations suppressed the plant growth,caused a reduction in leaf relative water contents(RWC)and elevated free proline and non-protein thiols(NPT)accumulation.Zinc treatment also led to enhanced lipid peroxidation(MDA contents)as well as the activity of ascorbate peroxidase(APX),showing the involvement of antioxidative defense mechanism to reduce Zn induced toxicity.IAA oxidase activity was also observed to increase due to Zn treatment.IAA pretreatment of H.vulgare caryopsis could partly revert the Zn-induced toxicity in seedlings.