Interaction between sulfur and lead in toxicity, iron plaque formation and lead accumulation in rice plant

作者：Junxing Yang, Zhiyan Liu, Xiaoming Wan, Guodi Zheng, Jun Yang, Hanzhi Zhang, Lin Guo, Xuedong Wang, Xiaoyong Zhou, Qingjun Guo, Ruixiang Xu, Guangdong Zhou, Marc Peters, Guangxu Zhu, Rongfei Wei, Liyan Tian, Xiaokun Han · 发表于：Ecotoxicology and Environmental Safety · 年份：2016 · DOI：10.1016/j.ecoenv.2016.02.021 · 被引用次数：69 · 研究领域：Heavy metals in environment、Arsenic contamination and mitigation、Plant Stress Responses and Tolerance

Human activities have resulted in lead and sulfur accumulation in paddy soils in parts of southern China. A combined soil-sand pot experiment was conducted to investigate the influence of S supply on iron plaque formation and Pb accumulation in rice (Oryza sativa L.) under two Pb levels (0 and 600 mg kg(-1)), combined with four S concentrations (0, 30, 60, and 120 mg kg(-1)). Results showed that S supply significantly decreased Pb accumulation in straw and grains of rice. This result may be attributed to the enhancement of Fe plaque formation, decrease of Pb availability in soil, and increase of reduced glutathione (GSH) in rice leaves. Moderate S supply (30 mg kg(-1)) significantly increased Fe plaque formation on the root surface and in the rhizosphere, whereas excessive S supply (60 and 120 mg kg(-1)) significantly decreased the amounts of iron plaque on the root surface. Sulfur supply significantly enhanced the GSH contents in leaves of rice plants under Pb treatment. With excessive S application, the rice root acted as a more effective barrier to Pb accumulation compared with iron plaque. Excessive S supply may result in a higher monosulfide toxicity and decreased iron plaque formation on the root surface during flooded conditions. However, excessive S supply could effectively decrease Pb availability in soils and reduce Pb accumulation in rice plants.