弱碱性农田土壤重金属污染对粉正蚓种群密度和生物量的影响研究
Effects of Heavy Metal Pollution on the Population Density and Biomass of Lumbricus rubellus from Weak Alkaline Farmlands

中文摘要：为了探讨弱碱性农田土壤重金属污染对粉正蚓 Lumbricus rubellus种群密度和生物量的影响，本研究于2016年5-8月，选取以重金属Cd、Pb、Zn、Cu污染为主的甘肃省白银市四龙镇梁庄村和双合村的玉米农田作为实验样地，同时以自然条件相近但相对无污染的永靖县尤塬村的玉米农田作为参照样地。本研究对比检测了实验样地与参照样地的重金属污染水平，粉正蚓种群密度、抗氧化酶活力（SOD、CAT和GSH-PX）、金属硫蛋白浓度和溶酶体膜损伤程度等指标。结果显示，2个实验样地粉正蚓抗氧化酶活力与参照样地的差异无统计学意义（ P>0.05），但金属硫蛋白浓度极显著高于参照样地（ P<0.01），表明粉正蚓在受到重金属污染胁迫后产生了明显的应激反应；与参照样地相比，实验样地粉正蚓体腔细胞内中性红保留时间极显著缩短（ P<0.01），表明土壤重金属污染已导致粉正蚓溶酶体膜受损；实验样地粉正蚓的种群密度和生物量与参照样地相比，总体上显著（ P<0.05）甚至极显著（ P<0.01）下降。研究结果表明，弱碱性农田土壤中粉正蚓种群密度与生物量显著低于相对无污染地区，这可能与长期重金属污染导致粉正蚓溶酶体膜损伤、抗氧化酶活力不稳定以及对环境胁迫应激反应增强等有关。
英文摘要：To investigate the toxic effect of heavy metal on the population density and biomass of Lumbricus rubellus from weak alkaline farmlands, in this study, the maize farmlands of Liangzhuang and Shuanghe villages in Baiyin city (Gansu province), which were mainly contaminated by Cd, Pb, Zn, and Cu for a long time, were selected as the study sites, and the maize farmlands of Youyuan village in Yongjing county which had similar natural conditions but with relatively unpolluted area was selected as the control site. The heavy metal contamination levels between the polluted and the control sites, the population density and biomass, antioxidant enzyme activities (SOD, CAT, GSH-PX), metallothionein (MT) concentration and lysosomal membrane damage degree of L. rubellus were comparatively studied. The results showed that there were no significant differences in the antioxidase activities of L. rubellus between the polluted and control sites, while extreme significantly higher MT concentration was found in the polluted sites ( P<0.01), indicating that L. rubellus from the polluted sites might be involved in stress responses; the test of neutral red retention time showed an extremely significant shortening in the coelomic cells of L. rubellus from the polluted sites ( P<0.01), this suggested that the lysosomal membrane was damaged; furthermore, the population density and biomass of L. rubellus were significantly ( P<0.05) or extremely declined ( P<0.01). According to the results of this study, we concluded that the significant decreased population density and biomass of L. rubellus from weakly alkaline sites might be related to the long-term heavy metal pollution which lead to the damage of lysosomal membrane, change of antioxidase activities and increased responses to the environmental stress. 2017,36(5): 507-512 收稿日期：2017-04-08 DOI：10.11984/j.issn.1000-7083.20170113 分类号：Q958.113;Q959.19 基金项目：国家自然科学基金项目（41171391） 作者简介：任梁(1991-),男,硕士研究生,研究方向:环境动物学,E-mail:renl2014@lzu.edu.cn