生态与农村环境学报2016，Vol.32Issue(2)：320-325,6.DOI:10.11934/j.issn.1673-4831.2016.02.023
Cd2＋和Cr3＋对崇明东滩湿地土壤碱性磷酸酶的低剂量兴奋效应
Low-Dose Hormetic Effects of Cd2+ and Cr3+on Alkaline Phosphatase in Wetland Soil in Dongtan of Chongming
摘要
Abstract
To explore low⁃dose hormetic effects ( a biphasic dose⁃response characterized by a low dose benefit and a high dose inhibition) of Cd2+ and Cr3+on activity of alkaline phosphatase in wetland soil, soil samples were collected from the wetland in Dongtan of Chongming, treated with different doses of Cd2+ and Cr3+, making the samples 0, 0�001, 0�01, 0�1, 1, 5, 10, 20, 100 and 500 mg·kg-1 in Cd2+ concentration and 0, 0�5, 5, 50 100, 500 and 5 000 mg·kg-1 in Cr3+ concentration, separately, and then incubated for 0, 6, 12, 24, 48, 72 and 120 hrs. After the incubation soil sam⁃ples were analyzed for activity of alkaline phosphatase ( ALP ) in soils to determine characteristics of the temporal variation of the activity with the incubation. Results show that after 12 hours of incubation, ALP activity was 8�6% higher in the soil samples 1 mg·kg-1 in Cd2+ concentration than in CK, and was obviously inhibited in the soil samples 10 mg·kg-1 in Cd2+ concentration( P<0�05) , while ALP activity was 22�8% higher in the soil samples 5 mg·kg-1 in Cr3+ concentration than in CK ( P<0�05) , but substantially lower in the soil samples 100 mg·kg-1 or higher in Cd2+ concentration, which indicates that the two types of heavy metals have some low⁃dose hormetic effects on ALP activity in the wetland soil, and the effects were closely related to duration of their contact. Meanwhile, after 24 hours of incubation, Vmax/Km( maximum reaction velocity/Michaelis constant) was 1�7 in the soil samples 1 and 5 mg·kg-1 in Cd2+concentration and lowered down to 0�8 in the soil samples 20�0 mg·kg-1 in Cd2+ concentration with both Vmax and Km being lower than their respective ones in CK ( soil samples 0 mg·kg-1 in Cd2+concentration) , and Vmax/Km was also 1�7 in the soil samples 1 and 5 mg· kg-1 in Cr3+ concentration, and 1�4 in the soil samples 100 mg·kg-1 in Cr3+ concentration, with both Vmax and Km being higher than their respective ones in CK. All the findings indicate that both Vmax and Km fall simultaneously in the presence of Cd2+, but rise simultaneously in the presence of Cr3+, and that the mechanism of low⁃case hormesis existing between heavy metals and soil enzymes may be closely related to properties of the heavy metal ions.关键词
低剂量兴奋效应/碱性磷酸酶/重金属/滨海湿地Key words
hormesis/alkaline phosphatase/heavy metal/coastal wetlands分类
资源环境引用本文复制引用
范弟武,徐莎,周曼丽,张倩楠,朱咏莉,韩建刚..Cd2＋和Cr3＋对崇明东滩湿地土壤碱性磷酸酶的低剂量兴奋效应[J].生态与农村环境学报,2016,32(2):320-325,6.基金项目
国家自然科学基金（41375149，41471191）；江苏高校优势学科建设工程资助项目（PAPD）；南京林业大学2015年度大学生实践创新训练计划 （）
