蕾期低温及湿度胁迫对Bt棉杀虫蛋白表达量的影响

以Bt基因来源于美国和我国的常规棉花品种DP410B和泗抗1号、杂交种岱杂1号和泗抗3号为材料，应用盆栽试验, 探讨蕾期18℃低温及不同湿度不同时间胁迫对叶片Bt杀虫蛋白表达量的影响。结果表明，蕾期18℃下不同湿度6 h胁迫对叶片Bt蛋白的含量都没有显著影响，但48 h胁迫导致2个不同Bt来源常规品种的叶片Bt杀虫蛋白表达量显著下降，与对照相比，下降6.8%~7.2%，杂交种泗抗3号也明显下降，岱杂1号则未受影响；18℃下高湿度与低湿度胁迫间没有显著影响。因此蕾期长时低温会对Bt棉抗虫性有一定影响，影响程度与品种及类型密切相关。

Effect on Stresses of 18°C and Different Relative Humidities on Bt Protein Expression at Squaring Stage in Bt Cotton

The objective of this study was to investigate the effect of stresses of 18°C and different relative humidities on the leaf resistance to the insect at squaring stage in Bt cotton. The two conventional cultivars (DP410B and Sikang 1) and two hybrids (Daiza 1 and Sikang 3) from the US and China, respectively, were used. The potted cotton plants were stressed at 18°C and different relative humidities (90%, 70%, and 50%) for 6 hours and 48 hours, respectively, then we determined leaf Bt protein contents. The results showed that the short period (6 hours) stresses of 18°C and different relative humidities obviously had no effect on the leaf Bt protein contents. but the leaf Bt protein contents sharply reduced in the two Bt conventional cultivars after the longer period (48 hours) stresses of 18°C and different relative humidities compared with the control, with the reduction from 6.8% to 7.2%. The leaf Bt protein content of hybrid Sikang 3 markedly decreased while that of hybrid Daiza 1 remained unchanged. There was no difference in the effect between the high relative humidity and low relative humidity at 18°C, so the low temperature duration may affect the Bt cotton resistance to insect at squaring stage, which is closely related to cultivars.