Bt棉功能叶氮代谢对Bt蛋白表达及氮肥调节的响应

为评价外源Bt基因插入以及氮肥对Bt棉功能叶Bt蛋白表达及氮代谢的影响,对Bt棉功能叶Bt蛋白含量,硝酸还原酶、谷丙转氨酶和蛋白酶活性,可溶性蛋白质和全氮含量等指标进行了测定。结果表明:Bt棉功能叶Bt蛋白含量在蕾期最高,此后,随生育进程呈显著下降。与常规棉相比,Bt棉功能叶硝酸还原酶活性提高,在前中期谷丙转氨酶活性显著提高且有利于可溶性蛋白质的合成,前期全氮含量显著增加,对蛋白酶活性没有明显影响。Bt棉功能叶Bt蛋白含量与硝酸还原酶活性、可溶性蛋白质和全氮含量呈显著正相关,表明Bt棉前期增强的氮代谢促进了Bt蛋白的表达。施氮肥明显提高Bt棉中后期功能叶硝酸还原酶活性、可溶性蛋白质含量和Bt蛋白的表达。基施和初花期各50%的效应显著大于全部基施,而在基施氮肥基础上,初花期增施50%的氮肥效应最明显。与常规棉比较,施氮肥更有利于Bt棉中后期功能叶硝酸还原酶活性、可溶性蛋白质含量提高。

Response of Nitrogen Metabolism in Functional Leaf to Bt Protein Expression and Nitrogen Fertilizer Adjustment for Bt Cotton

To investigate the effect of Bt gene and N fertilizer on Bt protein and nitrogen metabolism of functional leaf of Bt cotton, Bt protein content, nitrate reductase （NR） activity, glutamic-pyruvie transaminase （GPT） activity, protease activity, soluble protein content and total N content of functional leaf were measured in this study. The results showed that Bt protein content in functional leaf of Bt cottons reached the highest at budding stage. From then on, Bt protein content reduced significantly. Compared with conventional cottons, the NR activity of functional leaf of Bt cottons was enhanced, also the GPT activity and soluble protein content was increased significantly before flowering stage, and the total nitrogen content was increased significantly before budding stage, while there was no significant effect on protease activity. There was a significant positive correlation between Bt protein content and NR activity, soluble protein content and total nitrogen content. It concluded that the enhanced nitrogen metabolism at early stage promoted the Bt protein expression. N fertilizer improved Bt protein expressing, NR activity and soluble protein content of functional leaf of Bt cotton at middle and later stages. 50% of N fertilizer respectively at the basal and the early flowering stages affected much more than that of N fertilizer at all the basal stage. And on all basis N fertilizer, the effect of increasing 50% of the nitrogen fertilizer application at early flowering stage was the most significant. Compared with conventional cotton, N fertilizer was more helpful for the increasing of NR activity and soluble protein content of functional leaf for Bt cotton at middle and later stages.