Langdon Caroline J, Piearce Trevor G, Meharg Andrew A, Semple Kirk T
Department of Soil Science, University of Reading, P.O. Box 233, Whiteknights, Reading, Berkshire RG6 6AB, United Kingdom.
Environ Toxicol Chem. 2003 Oct;22(10):2344-8. doi: 10.1897/02-554.
No unequivocal evidence exists of genetically inherited resistance to metals/metalloids in field populations of earthworms. We studied cocoon production in adult Lumbricus rubellus Hoffmeister collected from an abandoned arsenic and copper mine (Devon Great Consols, Devon, UK), and abandoned tungsten mine (Carrock Fell, Cumbria, UK) and an uncontaminated cultured population. The earthworms were kept in uncontaminated soil for nine weeks. From a total of 42 L. rubellus from each site, Devon Great Consols adults produced 301 cocoons, of which 42 were viable; Carrock Fell 60 cocoons, of which 11 were viable; and the reference population 101 cocoons, of which 62 were viable. The hatchlings were collected and stored at 4 degrees C at weekly intervals. After 12 weeks, all hatchlings were transferred to clean soil and maintained at 15 degrees C for 20 weeks until they showed evidence of a clitellum. In toxicity trials, F1 generation L. rubellus were exposed to 2,000 mg As/kg as sodium arsenate or 300 mg Cu/kg as copper chloride for 28 d. The F1 generation L. rubellus from Devon Great Consols mine demonstrated resistance to arsenate but not copper. All L. rubellus from Devon Great Consols kept in soil treated with sodium arsenate remained in good condition over the 28-d period but lost condition rapidly and suffered high mortality in soil treated with copper chloride. The control population suffered high mortality in soil treated with sodium arsenate and copper chloride. Previous work has shown that field-collected adults demonstrate resistance to both arsenate and Cu toxicity under these conditions. Thus, while arsenate resistance may be demonstrated in F1 generation L. rubellus from one of the contaminated sites, Cu resistance is not. The F1 adults and F2 cocoons did not have significantly higher levels of As than the control population, with no residual As tissue burden, suggesting that resistance to As in these populations may be inherited.
在蚯蚓的野外种群中，不存在关于对金属/类金属的遗传抗性的确切证据。我们研究了从废弃的砷铜矿（英国德文郡的大康索尔，德文郡）、废弃的钨矿（英国坎布里亚郡的卡罗克山）以及未受污染的养殖种群中采集的成年红正蚓（Lumbricus rubellus Hoffmeister）的茧产量。将蚯蚓置于未受污染的土壤中9周。每个地点共42只红正蚓，来自德文郡大康索尔的成年蚯蚓产出301个茧，其中42个可存活；来自卡罗克山的产出60个茧，其中11个可存活；对照种群产出101个茧，其中62个可存活。每隔一周收集幼蚓并在4℃下保存。12周后，将所有幼蚓转移到清洁土壤中，并在15℃下饲养20周，直到它们出现环带迹象。在毒性试验中，将F1代红正蚓暴露于2000 mg As/kg的砷酸钠或300 mg Cu/kg的氯化铜中28天。来自德文郡大康索尔矿的F1代红正蚓表现出对砷酸盐的抗性，但对铜没有抗性。在28天的时间里，所有来自德文郡大康索尔且置于用砷酸钠处理过的土壤中的红正蚓都保持良好状态，但在置于用氯化铜处理过的土壤中时，很快就状态不佳并死亡率很高。对照种群在经砷酸钠和氯化铜处理的土壤中死亡率很高。先前的研究表明，在这些条件下，野外采集的成年蚯蚓对砷酸盐和铜毒性均表现出抗性。因此，虽然来自其中一个污染地点的F1代红正蚓可能表现出对砷酸盐的抗性，但对铜的抗性并未表现出来。F1代成年蚯蚓和F2代茧中的砷含量并不显著高于对照种群，且没有砷的残留组织负荷，这表明这些种群对砷的抗性可能是可遗传的。
