转Bt基因水稻残留秸秆对农田底栖动物的影响

为研究转Bt基因水稻秸秆残留对稻田内底栖动物的潜在影响,利用转Bt基因水稻“华恢1号”及其亲本“明恢63”的秸秆进行稻田填埋试验,分析转Bt基因水稻秸秆中Bt蛋白对秸秆分解和底栖动物多样性的影响. 结果表明:①在填埋的水稻秸秆上共发现223个底栖动物,分属9个科,其中,在转Bt基因和非转基因水稻秸秆上均发现7个科. ②秸秆种类和秸秆填埋时间对底栖动物丰度、物种数、Shannon-Wiener多样性指数、辛普森优势集中性指数(Simpson diversity index)和Pielou均匀度指数均无明显影响. ③转Bt基因和非转基因水稻秸秆剩余率均随着填埋时间的延长而逐渐降低,填埋7周后,两种类型秸秆剩余率平均值均为44.0%,二者之间无明显差异. ④在填埋的7周内,转Bt基因水稻秸秆中w(Bt蛋白)平均值为1.99~3.04 μg/g,7周后为2.04 μg/g. 研究显示,稻田残留的转Bt基因水稻秸秆对底栖动物多样性无显著影响. 

Effects of Remaining Bt-Transgenic Rice Straws on Benthos Communities in Fields

To detect the potential effects of Bt-transgenic rice straws remaining in fields on benthos communities, transgenic Cry1Ab/Ac rice “Huahui-1” and its non-transgenic parent rice “Minghui-63” were buried in paddy fields for seven weeks. We analyzed the differences of biodiversity indices of benthos communities and decomposition rate between Bt-transgenic and non-transgenic rice straws. The concentration of Bt (Cry1Ab/Ac) protein in transgenic rice straws was measured using a quantified ELISA method. 1) In total, 223 benthos were found on all Bt-transgenic and non-transgenic rice straws, and the benthic species belonged to nine families. Seven families were found on Bt rice straws and on non-Bt rice straws. 2) Neither the rice straw type nor the harvest time had an effect on benthos abundance and species number, the Shannon-Wiener index, Simpson diversity index or Plelou evenness of benthos communities. 3) The percentage of residual straws decreased with buried time, and was not significantly different between Bt-transgenic and non-transgenic rice straws; both Bt-transgenic and non-transgenic rice straws remained at 44.0% of dry weight after being buried seven weeks in the field. 4) The average concentration of Bt protein in transgenic rice straws varied between 1.99-3.04 μg/g during the bury period; the Bt protein content in transgenic rice straws had no significant difference among five harvesting times and was 2.04 μg/g after being buried seven weeks. These results showed that Bt-transgenic rice had no obvious effect on the biodiversity of benthos communities.