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作 者 ：武云杰，张小全，段旺军，杨铁钊*

期 刊 ：西北植物学报 2012年 10期 页码：2082~2088

关键词：烤烟；氨气挥发；氨气补偿点；质外体；谷氨酰胺合成酶(GS)抑制剂；

Keywords:flue-cured tobacco, ammonia volatilization, NH3 compensation point, apoplast, GS inhibitor,

摘 要 ：以烤烟品种K326为试验材料，利用氨气收集装置测定烟叶的氨气挥发量，并利用谷氨酰胺合成酶（GS）抑制剂（Glufosinate）处理叶片和质外体提取等方法，研究了叶片氨气挥发及其与氮代谢相关生理指标的关系。结果表明：（1）随着叶片的衰老，氨气挥发量在叶龄70 d时最大(10.96 μg·m^-2·h^-1)，与衰老初期（叶龄40 d）相比增加了2.15倍；质外体NH₄⁺浓度和pH、氨气补偿点逐渐上升，GS和硝酸还原酶（NR）活性下降，谷氨酸脱氢酶（GDH）活性升高，可溶性蛋白和总氮降解，叶片NH4⁺浓度升高。（2）GS抑制剂处理后，叶片组织NH₄⁺浓度和氨气补偿点升高，氨气挥发量增大，与对照相比差异显著。（3）氨气挥发量与质外体NH₄⁺浓度、质外体pH和氨气补偿点呈极显著或显著正相关，与GS活性呈显著负相关，与GDH活性呈显著正相关，与叶片组织NH₄⁺浓度等其他指标相关性不显著。研究认为，烤烟叶片衰老期间氨挥发量大幅上升，挥发量的大小受气孔氨气补偿点、GS和GDH活性的直接调控，以及其他氮素代谢相关指标的间接调控，其中GS起主导作用。

Abstract:With K326 varieties in flue-cured tobacco as the test materials,ammonia collection device and glutamine synthetase (GS) inhibitor (Glufosinate) handling leaves and the apoplast extraction method to study the relationships between ammonia volatilization and physiological parameters related with nitrogen metabolism.The results show that:(1)GS plays a leading role as the leaf senescence,the amount of ammonia volatilization in the age of 70 d is the largest (10.96 μg·m^-2·h^-1),increased of 2.15 times compared to that of aging initial (age 40 d);Apoplastic NH₄⁺ concentration and pH,ammonia compensation point gradually increased;GS and nitrate reductase (NR) activities decreased,glutamate dehydrogenase (GDH) activity increased;soluble protein and total nitrogen degradation,leaf NH₄⁺ concentration increased.(2) With GS inhibitor,leaf tissue concentrations of NH₄⁺ and ammonia compensation point increased,the amount of ammonia volatilization was increased significantly,compared with the control.(3)The amount of ammonia volatilization and apoplastic NH₄⁺ concentration,apoplastic pH and ammonia compensation point were significant or extremely significant and positively correlated;And the activity of GS was negative significantly correlated;And GDH activity was positively correlated with the concentration of NH₄⁺;and blade organization NH₄⁺ concentration and other index is not significantly related.In summary,flue-cured tobacco leaves during senescence of ammonia volatilization volume increased significantly.It is regulated directly with ammonia compensation point,GS and GDH activities,as well as adjusted indirectly with other nitrogen metabolism indexes,in which GS plays the leading role.

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