摘要：Bt com,a transgenic crop,was improved genetically to produce the insecticidal toxin encoded by the crylAb gene.In this study,possible effects of gene insertion were assessed by means of nutritional composition and antioxidant defence properties in com grains.Total protein and total oil contents were lower in Bt corn grains while proline and MDA levels of Bt corn were significantly higher when compared to non-Bt com grains.Fatty acid and carbohydrate compositions exhibited significant differences between the genotypes.In both genotypes,the most abundant fatty acids were linoleic and oleic acids.The most remarkable alteration in carbohydrate composition was ten times higher saccharose accumulation of Bt com.Total phenolic and total flavo-noid levels of Bt com were significantly lower than non-Bt counterpart.Antioxidant enzyme activities were evaluated in 48 hours-imbibed and 48 hours-germinated grains ofBt and non-Bt com.According to superoxide dismutase (SOD),guaiacol-peroxidase (POD) and glutathione reductase (GR) activities,genetic modification brought about remarkable alterations in antioxidant defence metabolism.
