:( 1 )将脱脂棉撕成小条沾取 0 .0 5%的卡那霉素溶液 ,粘附于棉花植株倒 2新生叶上。 5d后所有沾有卡那霉素溶液的感虫棉株的叶片均出现明显的黄色斑块 ,而转 Bt基因抗虫棉的叶片仍为正常绿色 ,无任何症状。 ( 2 )转 Bt基因抗虫棉种子接种于加有 1 0 0 0 mg· l- 1卡那霉素的 MS培养基中。四天后 ,抗虫棉子叶均表现为正常绿色 ,而常规品种子叶全为黄色 ,表明卡那霉素间接鉴定法是鉴定转 Bt基因抗虫棉的简便而又准确的方法 : (1) Tissue the absorbent cotton and strip it with 0,05% kanamycin solution and attach it to 2 new leaves of cotton plants. After 5 days, all the susceptible cotton plants stained with kanamycin had obvious yellow patches on their leaves, while the leaves of transgenic Bt cotton remained normal green with no symptoms. (2) Transgenic Bt cotton seeds were inoculated into MS medium supplemented with 1000 mg / L kanamycin. Four days later, the resistant cotton seedlings showed normal green color, whereas the conventional varieties showed yellow cotyledons, indicating that the kanamycin indirect identification method is a convenient and accurate method for identifying transgenic Bt cotton