施氮量对烤烟成熟期中部烟叶碳氮代谢及相关基因表达的影响

Effects of nitrogen application rate on carbon and nitrogen metabolisms and related gene expression in middle leaves of flue-cured tobacco at mature stage

为探明不同施氮量处理对烤烟碳氮代谢的影响,以烤烟品种豫烟10号为材料进行试验,施氮量分别设置低氮(22.5 kg/hm^2)、中氮(26.25 kg/hm^2)和高氮(30 kg/hm^2)3个处理,研究烤烟成熟期中部烟叶细胞的超微结构、碳氮代谢产物的变化规律和碳氮代谢途径相关基因的表达模式。结果表明:随土壤氮肥施用量的增加,烟叶细胞中淀粉粒体积增大,烟叶总糖和还原糖含量降低,淀粉和总氮含量增加。碳代谢关键基因AGPase的表达量随烟叶的生长而增加,但增加量随施氮量的增加而逐渐减少;氮代谢关键基因NR的表达量则随施氮量的增加而下降。

To investigate the effects of nitrogen application rate on the carbon and nitrogen metabolisms of flue-cured tobacco, field experiments were conducted on cv. Yuyan 10. Three treatments were set as following： low nitrogen （22.5 kg/hm^2）, moderate nitrogen （26.25 kg/hm^2） and high nitrogen （30 kg/hm^2）. The cell ultrastructure, variations of carbon and nitrogen metabolites and related gene expression patterns of middle leaves of flue-cured tobacco at mature stage were analyzed. The results showed that with the increase of nitrogen application rate, the starch grain volume in cells and the contents of starch and total nitrogen in tobacco leaves increased, while the contents of total sugar and reducing sugar decreased. With the growth of tobacco leaves, AGPase gene （a key gene in carbon metabolism） expression increased, but the increase rate decreased with the increase of nitrogen application rate. NR gene （a key gene in nitrogen metabolism） expression decreased with the increase of nitrogen application rate.