Effect of Kinetin on Physiological and Biochemical Properties of Maize Seedlings under Arsenic Stress

The effects of different levels of kinetin (KT) application on the growth, biomass, contents of chlorophyll (Chl a, Chl b, and carotenoid), arsenic uptake, and activities of antioxidant enzymes in maize seedlings under arsenic (As) stress were investigated by a hydroponic experiment. The results showed that KT supplementation increased the biomass in terms of root length, root number, fresh weight, and seedling length, and KT treatments also improved the contents of Chl a, As uptake, and Chl a : b ratio compared to cases with As treatment alone. However, no significant changes were observed in carotenoid content, and a reduction was found in Chl b content of seedlings. KT also increased the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in the leaves of maize seedlings when 0.1 mg/L KT and As were applied, which decreased the content of malondialdehyde (MDA). These results suggested that KT could alleviate the toxicity of As to maize seedlings by keeping the stability of chlorophyll, enhancing the activities of antioxidant enzymes, and inhibiting the lipid peroxidation. In conclusion, the alleviation effect of KT in maize seedlings exposed to As stress was clearly observed in the present study.