氮素水平对烟草幼苗生长发育及碳氮代谢关键酶活性的影响

Effects of Nitrogen Levels on Seedlings Growth and Key Enzyme Activities for Carbon and Nitrogen Metabolism of Flue-cured Tobacco

采用盆栽种植,以烟草K326为试验材料,CO(NH2)2为氮源,研究了4个氮素水平(0.1%、0.2%、0.3%和0.4%)对烟草生长发育及碳氮代谢关键酶活性的影响。结果表明,高氮对烟草幼苗的生长发育造成了一定程度的胁迫,导致植株矮小,叶片发黄;随着氮素处理水平的提高,烟碱含量下降,可溶性糖含量先下降后上升;谷氨酸合成酶活性先上升后下降,谷氨酰胺合成酶和谷氨酸脱氢酶呈上升的趋势,硝酸还原酶活性先降低后升高;而淀粉酶、蔗糖转化酶、蔗糖合成酶和蔗糖磷酸合成酶活性呈上升的趋势。在高氮水平下,碳代谢活性增强,而氮代谢水平降低。相关分析表明,CO(NH2)2水平与烟碱含量呈负相关。

In this experiment,the effects of differentnitrogen levels(0.1%,0.2%,0.3% and 0.4%)on the key enzyme activities of carbon and nitrogen metabolism of tobacco K326 was studied with potted planting based on CO(NH2)2.The results showed that high nitrogen leves inhibted tobacco plants growth and caused toyellow leaves. With the increase of nitrogen treatment level,nicotine content decreased and soluble sugar content first decreased and then increased. The activity of glutamate synthase first increased and then decreased,while that of glutamine synthase and glutamate dehydrogenase increased,and that of nitrate reductase decreased and then increased with increasing nitrogen level. The activities of amylase,sucrose invertase,sucrose synthase and sucrose phosphate synthase increased with increasing nitrogen level. All indicated high nitrogen level induced carbon metabolism,but inhited nitrogen metabolism. The correlation analysis showed that CO(NH2)2 level was negatively correlated with nicotine content.