谷氨酰胺合成酶抑制剂对衰老期烟叶氮代谢的影响

通过质外体提取和测定氮素代谢相关酶等方法，调查了不同浓度谷氨酰胺合成酶（GS）抑制剂（Glufosinate）对2个氮效率烤烟品种氮代谢相关生理指标的影响。结果表明，GS抑制剂可以有效抑制衰老期间烟叶GS活性，使氮素再同化能力下降，促进氮素营养物质的降解，并诱导谷氨酸脱氢酶（GDH）活性升高和硝酸还原酶（NR）活性下降，使叶片NH₄⁺积累，增大了氨气挥发潜力，且随着GS抑制剂浓度的升高，抑制效果更加明显。氮低效品种与氮高效品种相比，衰老速度快，叶片NH₄⁺的积累量小，氨气挥发潜力大，品种间差异显著。GS抑制剂可以加速叶片衰老，促进氮素降解和再转移。

The Influence of Glutamine Synthetase Inhibitors on Nitrogen Metabolism ofTobacco Leaves during Senescence Period

By using the method of apoplast extraction and determination of enzymes related nitrogen metabolism, the influence ofGlufosinate （GS） inhibitor concentrations on nitrogen metabolism physiological indices of flue-cured tobacco varieties with twonitrogen use efficiency were studied. The results show that GS inhibitors could inhibit GS activity of tobacco leaf during senescence,reduce the ability of nitrogen assimilation, promote the degradation of nitrogen nutrient, induct the increasing of glutamatedehydrogenase （GDH） activity and decreasing of nitrate reductase （NR） activity and promote accumulation of leaf NH4＋, increaseammonia volatilization potential. These inhibition effects became more obvious with increasing GS inhibitor concentration.Compared with high nitrogen efficiency varieties, low nitrogen efficiency varieties aged more rapidly and had a lower NH4＋accumulation and ammonia volatilization potential. There was significant difference between varieties. This shows that GS inhibitorscan accelerate leaf senescence and promote nitrogen degradation and transfer.