转Bt水稻种植与杀虫剂使用对土壤线虫群落的影响
Effects of transgenic Bt-rice and insecticides on the community structure of soil nematodes

为明确转Bt水稻对稻田土壤生物群落的生态风险性,于2012—2013连续2年大田试验调查研究了杀虫剂与转Bt水稻双因子对土壤线虫群落的影响。2年共监测到土壤线虫29个属,其中潜根线虫属Hirschmanniella、托布利线虫属Tobrilus、矛线线虫属Dorylaimus和丝尾垫刃线虫属Filenchus为优势属,相对多度分别为27.12%~37.92%、18.33%~24.19%、10.94%~14.87%和4.59%~15.76%;植物寄生类线虫和捕食-杂食类线虫为优势营养类群,相对多度分别为35.38%~47.62%和39.23%~48.52%;食细菌类线虫和食真菌类线虫的相对多度较低,分别为11.09%~15.20%和0.57%~1.69%。稻田土壤线虫数量、各个营养类群数量、组成以及群落生态指数随季节变化明显;在施用或不施用杀虫剂下转Bt水稻与非转Bt水稻间的土壤线虫数量及群落多样性指数显著影响;但与不施用杀虫剂的稻田相比,施用杀虫剂的转Bt水稻或非转Bt水稻的土壤线虫数量均显著减少。研究表明,转Bt基因水稻对土壤线虫群落的影响较小,而杀虫剂影响较大。
To clarify the potential environmental risk of Bt-rice plantations, the potential effects of transgenic Bt-rice plantation and insecticide application on nematodes communities were evaluated during 2012—2013. Twenty-nine genera of soil nematodes were identified in this study. Hirschmanniella, Tobrilus, Dorylaimus and Filenchus were dominant and the corresponding relative abundances were 27.12%-37.92%, 18.33%-24.19%, 10.94%-14.87% and 4.59%-15.76%, respectively. Moreover, herbivores and omnivore-predators nematodes were dominant groups, ranging from 35.38%-47.62% and 39.23%-48.52%, respectively. However, bacterivores and fungivores were relatively low, ranging from 11.09%-15.20% and 0.57%-1.69%, correspondingly. The number and composition of each guilds, ecological index and characteristics of communities were significantly changed with season. The number of nematodes and community diversity index in Bt-rice field were not significantly different from that of non-Bt-rice field, irrespective of insecticide application status. However, insecticide application significantly decreased the total number of nematodes, whether in Bt-rice or non-Bt-rice. The results indicated that the influence of Bt-rice plantation on community of soil nematodes was less important than that of insecticide application.