Effect of different N fertilizer forms on antioxidant capacity and grain yield of rice growing under Cd stress

Abstract

Cadmium contamination in soil has become a serious issue in sustainable agriculture production and food safety. A pot experiment was conducted to study the influence of four N fertilizer forms on grain yield, Cd concentration in plant tissues and oxidative stress under two Cd levels (0 and 100 mg Cd kg −1 soil). The results showed that both N form and Cd stress affected grain yield, with urea-N and NH 4 +-N treatments having significantly higher grain yields, and Cd addition reducing yield. NO 3 −-N and NH 4 +-N treated plants had the highest and lowest Cd concentration in plant tissues, respectively. Urea-N and NH 4 +-N treatments had significantly higher N accumulation in plant tissues than other two N treatments. Cd addition caused a significant increase in leaf superoxide dismutase (SOD) and peroxidase (POD) activities for all N treatments, except for NO 3 −-N treatment, with urea-N and NH 4 +-N treated plants having more increase than organic-N treated ones. The results indicated that growth inhibition, yield reduction and Cd uptake of rice plants in response to Cd addition varied with the N fertilizer form.