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采用网袋法在田间研究了Bt(Bacillus thuringiensis)玉米(Zea may)1246×1482和H9235Bt/RR秸秆中Bt蛋白的降解动态,并应用移动对数模型进行拟合及估算DT50和DT90,探讨不同还田方式对降解的影响。结果表明:1246×1482和H9235Bt/RR秸秆中Bt蛋白在埋入土壤和地表覆盖2种还田方式下均能在7d内降解90%以上,但还田180d时仍能检测到占初始含量0.004%～0.069%的Bt蛋白;不同还田方式并没有显著影响到1246×1482秸秆中Bt蛋白的降解过程,其埋入土壤和地表覆盖处理的DT50分别为0.90d和0.79d,DT90则分别为3.45d和5.03d;但不同还田方式影响了另一Bt玉米H9235Bt/RR秸秆中Bt蛋白的降解过程,在秸秆还田前期,埋入土壤处理下Bt蛋白的降解比地表覆盖处理慢,其埋入土壤和地表覆盖处理下Bt蛋白降解的DT50分别为6.80d和0.54d,DT90则分别为21.76d和7.12d。由此可见,2个Bt玉米品种秸秆中Bt蛋白在2种还田方式下均能快速降解,不同还田方式只影响到H9235Bt/RR秸秆中Bt蛋白的田间降解,使得地表覆盖处理下Bt蛋白的降解比埋入土壤处理快。
The degradation of Bt protein in Bt (Bacillus thuringiensis) maize (Zea mays) 1246 × 1482 and H9235Bt / RR straw was studied by using mesh bag method. The moving logarithm model was used to fit and estimate DT50 and DT90, Effect of returning to field on degradation. The results showed that Bt protein in 1246 × 1482 and H9235Bt / RR straw degraded more than 90% within 7 days after being buried in soil and covered with 2 kinds of soil cover. However, the content of Bt protein was still 0.004 % ~ 0.069% of Bt protein. The different ways of returning the Bt protein did not significantly affect the degradation of Bt protein in 1246 × 1482 straw. The DT50 of soil B and B were 0.90d and 0.79d, respectively, 3.45d and 5.03d, respectively. However, the biodegradation of Bt protein in Bt corn H9235Bt / RR straw was affected by different ways of returning to the soil. In the early stage of straw returning, the degradation of Bt protein was slower than the surface mulching treatment The DT50 of Bt degradation was 6.80d and 0.54d respectively under the soil and surface cover treatments, while the DT90 was 21.76d and 7.12d respectively. Thus, the Bt protein in two Bt corn varieties could be rapidly degraded in two kinds of straw returning methods. The different returning methods affected only the degradation of Bt protein in the H9235Bt / RR straw, which made the Bt protein Degradation than buried in soil treatment faster.