Yang Junxing, Liu Zhiyan, Wan Xiaoming, Zheng Guodi, Yang Jun, Zhang Hanzhi, Guo Lin, Wang Xuedong, Zhou Xiaoyong, Guo Qingjun, Xu Ruixiang, Zhou Guangdong, Peters Marc, Zhu Guangxu, Wei Rongfei, Tian Liyan, Han Xiaokun
Center for Environmental Remediation, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China.
School of Life Sciences, South China Normal University, Guangzhou 510631, PR China.
Ecotoxicol Environ Saf. 2016 Jun;128:206-12. doi: 10.1016/j.ecoenv.2016.02.021. Epub 2016 Mar 4.
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.
人类活动已导致中国南方部分地区稻田土壤中铅和硫的积累。开展了一项土壤-沙子联合盆栽试验，以研究在两种铅水平（0和600毫克/千克）下，硫供应对水稻（Oryza sativa L.）中铁膜形成和铅积累的影响，并结合四种硫浓度（0、30、60和120毫克/千克）。结果表明，硫供应显著降低了水稻秸秆和籽粒中的铅积累。这一结果可能归因于铁膜形成的增强、土壤中铅有效性的降低以及水稻叶片中还原型谷胱甘肽（GSH）的增加。适量的硫供应（30毫克/千克）显著增加了根表面和根际的铁膜形成，而过量的硫供应（60和120毫克/千克）显著降低了根表面的铁膜量。硫供应显著提高了铅处理下水稻植株叶片中的GSH含量。与铁膜相比，过量施硫时，水稻根系对铅积累起到了更有效的屏障作用。过量的硫供应可能导致更高的单硫化物毒性，并在淹水条件下减少根表面的铁膜形成。然而，过量的硫供应可以有效降低土壤中铅的有效性，并减少水稻植株中的铅积累。
