转cry1Ac基因抗虫棉对土壤三种酶活性的影响

为了明确转cry1Ac基因抗虫棉对土壤酶活性的影响，本研究采集转cry1Ac基因抗虫棉及其亲本棉‘SM 3’种植地的土壤，测定转cry1Ac基因抗虫棉及其亲本棉 ‘SM 3’不同生育期内根区距主根不同距离土壤脱氢酶、脲酶和磷酸酶活性的变化。结果表明，棉花根区土壤脱氢酶活性在整个生育期呈现出先升高后降低再升高的变化趋势，土壤脲酶和磷酸酶活性在整个生育期无明显的起伏变化。转基因棉‘GK 12’盛花期和枯死期根区5 cm的土壤脱氢酶活性显著高于亲本棉‘SM 3’（p<0.05），转基因棉‘GK 12’盛花期根区15 cm和25 cm的土壤脱氢酶活性也显著高于亲本棉‘SM 3’（p<0.05）；在棉花蕾期，转基因棉‘GK 12’根区5 cm和15 cm的土壤磷酸酶活性显著高于亲本棉‘SM 3’（p<0.05），而对根区25 cm的土壤磷酸酶活性无显著影响（p>0.05）；转基因棉‘GK 12’在整个生育期对不同距离土壤脲酶活性无显著影响（p>0.05）。上述结果初步看出，在棉花生长的一些生育时期，转cry1Ac基因抗虫棉‘GK 12’对根区土壤酶活性存在明显的影响，但其影响的程度不是很大，后期基本可得到恢复。

Effects of transgenic cotton containing cry1Ac gene on the activities of three enzymes in soils

Soil samples were collected from transgenic cotton ‘GK 12’ and non transgenic cotton ‘SM 3’ fields to study the effects of cry1Ac cotton ‘GK 12’ on soil enzyme activities. The soil dehydrogenase, urease and phosphatase enzyme activities in different root distances were determined at different growth stages. The results showed that the soil dehydrogenase activity in the cotton root zone during the whole growth period increased, decreased and then increased. However, there was no significant change in soil urease and phosphatase activities during the whole growth period. Significantly higher soil dehydrogenase activity was observed during the flowering and withering periods in the 5 cm root zone of the transgenic cotton ‘GK 12’ compared with the non transgenic cotton ‘SM 3’ (p<0.05). The soil dehydrogenase activity was significantly higher during the flowering period in the 15 cm and 25 cm root zones of transgenic cotton ‘GK 12’ compared with the non transgenic cotton ‘SM 3’ (p<0.05). Significantly higher soil phosphatase activity was observed at the budding stage in the 5 cm and 15 cm root zones of transgenic cotton ‘GK 12’ compared with non transgenic cotton ‘SM 3’ (p<0.05), while no effects on soil phosphatase activity in 25 cm root zone of transgenic cotton ‘GK 12’ (p>0.05). There was also no significant effects on soil urease activity in different distances during the whole growth period of transgenic cotton ‘GK 12’ compared with non transgenic cotton ‘SM 3’ (p>0.05). It indicated that transgenic cry1Ac cotton ‘GK 12’ had some effects on soil enzyme activities at a given growth stage of transgenic cotton. But it would be recovered at later growth stages.