作　　者： ; ; ;

机构地区： 华南农业大学农学院热带亚热带生态研究所

出　　处： 《生态学报》 2003年第4期797-804,共8页

摘　　要： 综述了转 Bt基因作物的 Bt毒素在土壤中的环境去向及其生态效应的研究进展。重点阐述了 :1 Bt毒素与土壤表面活性颗粒结合及其与土壤理化性质的关系 ;2 Bt毒素微生物利用与降解 ;3Bt毒素的杀虫活性 ;4后茬作物和土壤动物对 Bt毒素的吸收与利用 ;5 Bt毒素的垂直运移 ;6 Bt毒素对土壤生物和生态过程的影响。转 Bt基因作物的 Bt毒素对土壤生态系统的影响急需在生态系统水平进行深入细致的长期定位研究。 There is controversy about the means of environmental risk assessment and management of transgenic crops because of the speed and quantity of these cr ops being planted, particularly those containing genes to produce the insecticid al toxin from Bacillus thuringiensis (Bt). Most research on Bt crops has foc used on invasiveness, gene flow to indigenous organisms, development of resistance i n target pests, and direct or indirect effects on non-target organisms and ecos y stems. However, after the commercially usable portion of Bt crops has been harve sted, the remainder of plant biomass containing the toxins is usually incorporat ed into soil. The toxin is also introduced into soil in root exudates and from p ollen during tasseling. This is raising concern about the effects of residual Bt toxins on the soil ecosystem. This review summarizes current research in six important areas related to the en vironmental fate of Bt toxin from Bt crops and its ecological effects in soil. ( 1) Bt toxins absorb rapidly onto mined clay minerals and the clay-size fraction of soil. Rapid adsorption and binding of Bt from root exudates and Bt corn biom ass onto surface-active particles in soil has been demonstrated in both in vitr o and in situ studies. (2) Binding of the toxin on surface-active particles can r educe their availability to microbes and hence biodegradation, which is probably responsible for their persistence in soil. Free Bt toxin is readily utilized as sole sources of carbon and nitrogen by pure and mixed cultures of microbes, whe reas the bound toxins are not utilized as a source of carbon and only slightly a s a source of nitrogen. The literature estimates the length of toxin persistence based on half-life' values range from 8～17 d for purified toxin and from 2～ 41 d for transgenic corn, cotton, and potato biomass. (3) The toxin released from b iomass or in root exudates of Bt corn, however, remains larvicidal for at least 180 d. Insect bioassays indicate that the Cry 1Ab protein of Bt corn t

关 键 词： 转 基因作物 毒素 土壤 环境去向 生态效应 土壤生物 土壤生态系统

领　　域： [农业科学] [农业科学]