<div><br></div><div><section class="_135editor" data-role="paragraph" style="font-size: medium; max-inline-size: 100%; margin: 0px; padding: 0px; border: 0px none; z-index: 0; overflow-wrap: break-word !important; outline: none 0px !important;"><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 14px; overflow-wrap: break-word !important; outline: none 0px !important;">　　经多年研究表明，转Bt基因和转Bt＋CpTI基因抗虫棉的抗虫性有以下特点：①抗虫性上有时空分布。转基因抗虫棉对棉铃虫的抗性表现为生育前期抗虫性强，中后期抗虫性弱。具体表现为，抗虫棉对二代棉铃虫的抗虫性最强，对三代、四代棉铃虫的整体抗虫性有所减弱。在相同的生长发育时期内，转Bt基因抗虫棉不同器官对棉铃虫的抗虫性不同，一般表现为，主茎功能叶＞果枝叶＞生殖器官。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 14px; overflow-wrap: break-word !important; outline: none 0px !important;">　　②抗虫性单一。主要是高抗棉铃虫、红铃虫和玉米螟，但对棉蚜、棉叶螨、棉盲蝽、棉蓟马和烟粉虱等非靶标害虫均无抗性。③抗虫活力随幼虫的龄期变大而降低。据试验，转基因抗虫棉对３龄前的棉铃虫小幼虫的致死力明显高于大龄幼虫。④环境因素影响棉株的抗性活力。试验表明，若花铃期转基因抗虫棉田严重渍涝或土壤缺水干旱，可显著减少棉株各器官的Bt蛋白含量，从而降低棉株的抗虫活力。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p></section><section class="_135editor" data-role="paragraph" id="autoparagraph" style="font-size: medium; max-inline-size: 100%; margin: 0px; padding: 0px; border: 0px none; z-index: 0; overflow-wrap: break-word !important; outline: none 0px !important;"><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; font-family: 微软雅黑, &quot;Microsoft YaHei&quot;, sans-serif; font-size: 17px; caret-color: rgb(255, 0, 0); overflow-wrap: break-word !important; outline: none 0px !important;"></p></section></div>