崇明东滩湿地土壤中Cr^3＋、Pb^2＋和Cd^2＋对硝酸还原酶的Hormesis效应  

Hormetic effects of Cr^(3+),Pb^(2+) and Cd^(2+) on nitrate reductase in soils in Chongming Dongtan wetlands

作　　者：印杰[1] 范弟武 徐莎[1] 韩建刚[1] 朱咏莉[1] 薛建辉[1] 

机构地区：[1]南京林业大学南方现代林业协同创新中心,南京林业大学生物与环境学院,江苏南京210037

出　　处：《南京林业大学学报（自然科学版）》2016年第2期21-26,共6页Journal of Nanjing Forestry University：Natural Sciences Edition

基　　金：国家自然科学基金项目(41471191,41375149);国家林业公益性行业科研专项项目(201404305);江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：为揭示典型滨海湿地土壤中重金属对土壤酶的低剂量兴奋效应(Hormesis),以崇明东滩湿地为对象,采集土壤样品,分别添加不同剂量的Cr^(3+)(0、0.5、5.0、50.0、500.0、5 000.0 mg/kg)、Pb^(2+)(0、10、30、50、100、300、500mg/kg)以及Cd^(2+)(0、0.1、1.0、5.0、10.0、100.0 mg/kg),观测土壤硝酸还原酶(NR)活性随时间(0、6、12、24、48、72、120 h)的变化特征。结果表明:与对照(重金属添加量0 mg/kg)相比较,低剂量Cr^(3+)(0.5~5.0 mg/kg)、Pb2+(10.0 mg/kg)和Cd^(2+)(0.1 mg/kg)均使NR活性显著升高(P<0.05),剂量效应曲线表现出明显的倒"U"形。这表明,Cr^(3+)、Pb^(2+)和Cd^(2+)与湿地土壤NR活性之间存在Hormesis剂量效应关系。刺激效应出现的时间分别为培养后的6~72 h(Cr^(3+))、24~120 h(Pb^(2+))和6~48 h(Cd^(2+)),幅度变化在56.4%~107.4%之间。因此,低剂量重金属对NR活性的刺激作用可能进一步影响湿地土壤硝态氮的还原过程,建议对崇明东滩湿地土壤中低微量重金属的环境影响进行系统评估。The objective of this study is to discover the hormetic effects （ a biphasic dose-response characterized by a low dose benefit and a high dose inhibition） between heavy metals and soil enzyme in a typical wetland. Soil samples were taken from Chongming Dongtan, a wetland in the Yangtze River Delta of China. The activities of nitrate reductase （NR） in soils were examined at O, 6, 12, 24, 48, 72 and 120 hrs incubation in the presence of Cr3＋（0.0, 0. 5, 5.0, 50. 0, 500. 0 and 5 000.0 mg/kg）, Pb2＋（0, 10, 30, 50, 100, 300 and 500 mg/kg） and Cd2＋（0. 0, 0. 1, 1.0, 5.0, 10. 0 and 100.00 mg/kg）, respectively. Results showed that low dosages of Cr3＋（0. 5-5.0 mg/kg）, Pb2＋（ 10. 0 mg/kg） and Cd2＋（0. 1 mg/kg） significantly enhanced NR activities comparing with that of the control （0.0 mg/kg metal ions added） （P〈0. 05）, showing a typical inverted U-shaped dose-response curve, respectively, which indicated that a hormetic dose-response relationship existed between the three metals and NR in softs. The hormetic effects occurred at time of 6- 72 h （ Cr3＋ ）, 24-120 h （ Pb2＋ ） and 6-48 h （ Cd2＋ ） incubations, respectively, with the maximum stimulatory response of 56.4%-107.4% greater than the control. Therefore, the hormetic effects imply that the enhanced NR activities possi- bly affect nitrate reduction in wetland soils. It is very necessary to define and evaluate the effects of low dose heavy met- als on soil functions in a wetland in the future.

关 键 词：滨海湿地 重金属 硝酸还原酶 Hormesis效应 崇明岛 

分 类 号：X53[环境科学与工程—环境工程] S19[农业科学—农业基础科学]