采用重铬酸钾容量法和红外光谱(FTIR）法分析了转基因抗虫棉花残体降解后的土壤腐殖质组分富里酸(FA）、 胡敏酸(HA）和胡敏素(HM）的含量和结构特征。 结果表明, 棉花残体的降解使土壤各腐殖质组分含量增加, 胡敏素的相对含量增加最大, 胡敏酸次之, 富里酸最小。 与相应非转基因对照相比, 转Bt基因棉花残体处理土壤各腐殖质组分含量降低, 转双价基因棉花SGK321处理含量增高, 转双价基因棉花Z41处理含量相当。 各腐殖质组分的光谱特征显示, 棉花残体的添加使土壤腐殖质中含氧基团减少、 烷基与酰胺化合物的比例有所降低; 不同转基因品种间棉花残体降解形成腐殖质的速度存在差异, 转Bt基因棉花残体较其对照慢, 转双价基因棉花SGK321残体较其对照快, 转双价基因棉花Z41残体与其对照相当。

After transgenic cotton residues incubated in soil 430 d, the contents and structural characteristics of soil humus fractions, fulvic acid, humic acid and humin were measured by potassium dichromate titrimetric method and Fourier transform infrared spectroscopy. The results showed that all soil humus fractions increased after the degradation of cotton residues, and the most relative increase was with humin and the least was with fulvic acid. Compared to their near-isogenic non-transgenic cottons, soil humus content for transgenic Bt cotton residue decreased, and that forr transgenic Bt+CpTI cotton Z41 was approximate, but that for transgenic Bt+CpTI cotton SGK321 increased. Infrared spectroscopy of fulvic acid, humic acid and humin showed the addition of cotton residue decreased the content of oxygenous groups, and increased the alkyl and amide groups. There were differences in the speed to form soil humus among three transgenic cottons. Transgenic Bt cotton was slower than its counterpart, transgenic Bt+CpTI cotton Z41 was approximate to its counterpart, but transgenic Bt+CpTI cotton SGK321 was faster than its counterpart.