| Transgenic cotton has played a pc,sitive role in promoting cotton production of China and the world.With the growth of planting area of the transgenic Bt CrylAc cotton year by year,people pay more attention to the safety of the release of transgenic crops.Deeply study of the Bt toxic protein content and residue in the soil after planting transgenic Bt cotton and non-Bt cotton,and the influence on the soil ecosystem balance and the soil invertase and urease activity are necessary conditions for sustainable development and healthy of Transgenic crops.Detecting content of Bt insecticidal crystalline protein(ICP) using the enzyme linked immuno sorbed assay(ELISA),the invertase activity and urease activity in rhizosphere and non-rhizosphere soil in different stages of transgenic Bt cotton and non-Bt cotton adopt a pot experiment,that can provide the effects of rhizosphere environment and a scientific basis for safety assessment of the soil ecosystem.The main results are outlined as follows:1.Content ofBt ICP in rhizosphere soil is more than in non-rhizosphere soil after planting transgenic Bt cotton and non-Bt cotton.Content of Bt ICP in bud stage of transgenic Bt cotton in rhizosphere soil is in the order of yellow cinnamon soil＞yellow brown soil＞red soil.Contents ofBt ICP oftransgenic Bt cotton were 1.44,1.21 and 2.38 times of non-Bt cotton in yellow cinnamon soil,yellow brown soil and red soil,separately. Content of Bt ICP in flowering and boll-setting period of transgenic Bt cotton in rhizosphere soil is in the order of yellow brown soil＞yellow cinnamon soil＞red soil. Contents of Bt ICP of transgenic Bt cotton were 1.56,1.16 and 1.97 times of non-Bt cotton in yellow brown soil,yellow cinnamon soil and red soil,separately.All of them are significantly differences.2.Content of Bt ICP of transgenic Bt cotton and non-Bt cotton in rhizosphere and non-rhizospher soil firstly increases,then decreases with time.The maximum values of Bt content of transgenic Bt cotton in rhizosphere soil are 3.67 ng/g in yellow cinnamon soil, 3.61 ng/g in yellow brown soil and 3.16 ng/g in red soil.And the minimum values of Bt content are 0.79 ng/g in yellow cinnamon soil,0.79 ng/g in yellow brown soil and 0.62 ng/g in red soil.Throughout the experimental period,content ofBt ICP in rhizosphere soil of transgenic Bt cotton is approximately more than of non-Bt cotton.The result show that more Bt ICP released to rhizosphere soil from transgenic Bt cotton than non-Bt cotton.3.The soil invertase activity in rhizosphere soil is approximately more than in non-rhizosphere soil after planting transgenic Bt cotton and non-Bt cotton.The soil invertase activity of transgenic Bt cotton in rhizosphere soil including bud stage and flowering and boll-setting period is in the order of yellow brown soil＞yellow cinnamon soil＞red soil.All of them are significantly differences.The soil invertase activity of transgenic Bt cotton in bud stage is 0.93 times of non-Bt cotton in yellow brown soil,1.14 times in yellow cinnamon soil and 1.02 times in red soil.And when in flowering and boll-setting period,that is 1.09 times,1.07 times and 1.24 times.4.The soil invertase activity of transgenic Bt cotton and non-Bt cotton in rhizosphere and non-rhizospher soil including yellow brown soil and yellow cinnamon soil firstly decreases,then increases with time.The minimum soil invertase activity of transgenic Bt cotton in rhizosphere soil are 28.17 mg/g in yellow cinnamon soil and 39.00 mg/g in yellow brown soil.And the maximum values of Bt content are 50.36 mg/g in yellow cinnamon soil and 63.68 mg/g in yellow brown soil.The soil urease activity of transgenic Bt cotton in rhizosphere soil in bud stage is in the order of yellow brown soil＞red soil＞yellow cinnamon soil.And they are no significant differences.And the soil urease activity in flowering and boll-setting period is in the order of yellow cinnamon soil＞red soil＞yellow brown soil.5.It is significantly difference between yellow cinnamon soil and red soil.It is no significantly difference between red soil and yellow brown soil.The soil urease activity in rhizosphere soil is more than in non-rhizosphere soil after planting transgenic Bt cotton. The soil urease activity of transgenic Bt cotton in bud stage is 2.02 times of non-Bt cotton in yellow cinnamon soil,1.87 times in yellow brown soil and 2.31 times in red soil.And when in flowering and boll-setting period,that is 0.96 times,0.88 times and 1.01 times.6.The soil urease activity of transgenic Bt cotton and non-Bt cotton in non-rhizosphere soil decreases with time.And the soil urease activity of transgenic Bt cotton in rhizosphere soil is similar to that.The soil urease activity of non-Bt cotton in rhizospher soil firstly increases,then decreases.The maximum soil urease activity of transgenic Bt cotton in rhizosphere soil are 0.82 mg/g in yellow cinnamon soil and 0.87 mg/g in yellow brown soil.And the minimum values of Bt content are 0.59 mg/g in yellow cinnamon soil and 0.41 mg/g in yellow brown soil.Throughout the experimental period,the soil urease activity in rhizosphere soil is more than of in non-rhizosphere soil. |
