In order to clarify that the increase of glutamine synthetase (GS) activity can improve salt tolerance in tobacco, this paper took cultivar tobacco K326 as control and studied TaGS1/TaGS2 transgenic tobacco salt tolerance and its mechanism. Results showed that under salt stress, TaGS1/ TaGS2 transgenic tobaccos, especially TaGS2 transgenic tobacco, had stronger root system and higher biomass than K326, and its ability to resist salt was superior to K326. TaGS1/TaGS2 transgenic tobacco had better carbon and nitrogen metabolism with higher chlorophyll content, stomatal conductance, net photosynthetic rate, GS activity, and soluble protein content. Content of proline and water of TaGS1/TaGS2 transgenic tobaccos were higher than that of K326, while content MDA of TaGS1/ TaGS2 transgenic tobaccos were lower than that of K326. Hence TaGS transgenic tobacco had stronger leaf osmotic regulation ability and plasma membrane protection ability. It was concluded that overexpression of TaGS1/TaGS2 could improve salt tolerance in tobacco, and its higher GS activity was the physiological basis to maintain high carbon and nitrogen metabolism and resistance to salt stress.%为了阐明提高谷氨酰胺合成酶(GS)活性是否可以提高烟草的耐盐能力,本试验以烟草栽培品种K326为对照,研究TaGS1/TaGS2转基因烟草抗盐能力及其机制.结果表明,盐胁迫条件下,过表达TaGS1/TaGS2烟草与对照相比,根系较发达,烟株生物量较高,TaGS2转基因烟草尤为显著;转基因烟草的叶绿素含量、气孔导度、净光合速率、GS活性、可溶蛋白含量等碳氮代谢功能均显著优于野生型K326;且转基因株系脯氨酸含量及含水量较高,MDA含量较低,叶片渗透调节能力和质膜保护能力比K326强.研究表明TaGS1/TaGS2的过表达提高了烟草的耐盐能力,其高GS活性是维持碳氮代谢抵抗盐胁迫的生理基础.
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