重金属-土壤酶的hormesis效应及其机理与风险研究- - 以伊犁河谷湿地为例

项目名称： 重金属-土壤酶的hormesis效应及其机理与风险研究- - 以伊犁河谷湿地为例

项目编号： No.41471191

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 地质学

项目作者： 朱咏莉

作者单位： 南京林业大学

项目金额： 86万元

中文摘要： 毒物兴奋效应（hormesis）普遍发生于各级生物对象。土壤酶作为土壤生态系统最具活性的生物大分子之一，参与几乎所有土壤生化反应。然而，土壤酶存在hormesis效应吗？目前还缺乏直接和足够的观测证据。以人为活动干扰较小的伊犁河谷湿地为原型区域，采集沉积物样品，借助标准酶、酶促反应动力学、微生物群落结构与多样性分析等技术和方法，研究Cu、Cd、Pb等重金属在独立与复合暴露下沉积物脲酶、碱性磷酸酶、硝酸还原酶活性等的变化，解析并明确三种酶的hormesis效应特征；基于酶结构与亲和力应激、微生物介体传导、底物交互激发与传递等过程探索效应发生机理；结合盆栽实验植物生化、生理和生物学指标等对三种酶hormesis效应剂量水平的响应，阐明土壤酶尺度重金属hormesis效应的潜在风险。项目研究将为土壤酶尺度是否存在hormesis效应提供直接证据，也无疑有助于土壤生态系统重金属环境效应的科学评估。

中文关键词： hormesis；重金属；土壤酶；湿地

英文摘要： Hormesis is defined to describe a stimulatory effect associated with a low dose of a potentially toxic substance or stress, which has been reported widely occurring to a variety of organisms. Soil enzyme, one kind of the most active biomacromolecules, is involved in almost all biochemistry reaction in soil ecosystem. However, can hormesis happen to soil enzyme? There is a lack of direct and sufficient observational evidence. The hormetic effects of Cu, Cd and Pb on urease, alkaline phosphatase and nitrate reductase in sediments from Ili riverside wetlands, a less human disturbance and clean area in Xinjiang province, China, are to be investigated in single and interactive metal ions systems via sediment incubation, with methods of standard enzymes, enzymatic reaction kinetics and analysis of microbial community structure and diversity. Based on adaptive responses in enzyme structure and affinity, microbe feedbacks and interactive motivation and delivery of effects from substrate stimulations, the hormetic mechanisms are also to be explored. Meanwhile, combined with the responses of biochemical, physiological and biological properties of plants to hormetic doses of heavy metal ions in sediments, the potential risks from the hormetic effects will be estimated by pot culture experiments. The present project aims to detect the hormetic effects that potentially occur to soil enzyme, which will extend the interests of hormesis fields and help to assess the effects of heavy metals on soil ecosystem.

英文关键词： hormesis;heavy metals;soil enzyme;wetlands