杨楷 郑宏斌 黄莺 冯新维 明堂

摘 要：试验采用土培方式，设置5个氮素水平来研究不同施氮量对烤烟氮代谢关键酶活性的影响。结果表明：施氮量在一定范围内对烤烟氮代谢关键酶活性均有促进作用，但过高则产生抑制，且不同酶、不同生育时期的作用浓度并不相同。移栽后7d，烟叶硝酸还原酶活性（NRa）随施氮量的增加呈先增加后降低的变化趋势，施氮量≤5.45g/株时，增施氮肥可促进NRa，有利于NO.-3向NH3的转化;>5.45g/株时，则因反应产物NO.-2或NH.+4浓度的增加抑制了NRa;烟叶谷氨酰胺合成酶活性（GSa）在旺长期和现蕾期时均随施氮量的增加呈先增加后降低的变化趋势，且GSa分别在5.45g/株、8.18g/株施氮量下达到最大值5.777U/g、18.713U/g，施氮量≤10.91g/株條件下增施氮肥可促进谷氨酸含成酶（GOGATa），≥10.91g/株时，则因Glu浓度过高抑制GOGATa。

关键词：烤烟;施氮量;酶活性

中图分类号：S572文献标识码：A

文章编号：1008-0457（2020）03-0075-05 国际DOI编码：10.15958/j.cnki.sdnyswxb.2020.03.013

Effect of Nitrogen Application on the Activity of Key Enzymes in Nitrogen Metabolism of Flue-Cured Tobacco

YANG Kai .1，3，ZHENG Hongbin.2，HUANG Ying .1，3*， FENG Xinwei .1，3， MING Tang .1

（1.College of Tobacoo Science，Guizhou University， Guiyang，Guizhou 550025，China;2.China Tobacco Zhejiang Industrial Co，Ltd.，Hangzhou，Zhejiang 310000，China;3. Key Laboratory of Tobacco Quality Research of Guizhou Province， Guiyang，Guizhou 550025，China）

Abstract：In order to explore the effects of different nitrogen application on the key enzyme activities of nitrogen metabolism in flue-cured tobacco， five nitrogen levels were used to study the effects of different application amount of nitrogen on the key enzyme activities of nitrogen metabolism in flue-cured tobacco by soil culture method. The results showed that the application amount of nitrogen could promote the activity of key enzymes in nitrogen metabolism of flue-cured tobacco within a certain range， but higher amount would produce inhibition effect， and the effect concentrations varied in different enzymes and different growth periods. Seven days after transplanting， NRa of tobacco increased first and then decreased with the increase of nitrogen application. When nitrogen application was ≤5.45g/plant， the additional application of nitrogen could promote NRa， which was beneficial to the conversion of NO.-3 to NH3. When it was >5.45g/plant，NRa was inhibited because of increasing the concentration of NO.-2 or NH.+4. The GSa increased first and then decreased with the increase of nitrogen application during the prosperous period and the bud stage， and that reached the maximum value of 5.777U/g， 18.713U/g under the treatments of 5.45g/plant， 8.18g/plant respectively. The increase of nitrogen application under the condition of nitrogen application ≤10.91g/plant could promote GOGATa.When it was ≥10.91g/plant，GOGATa was inhibited due to excessive Glu concentration.

Keywords：flue-cured tobacco; nitrogen application amount; enzyme activity

氮代谢是烟草最基本、最重要的代谢之一，其代谢强度、协调程度及在烟叶生长发育过程中的变化动态对烟叶品质形成具有重要影响[1-2]。外源氮浓度对烤烟氮代谢关键酶活性有着重要影响，据岳红宾[3]、许晨曦[4]等报道，随着外源氮素水平的提高，叶片中硝酸还原酶（NR）的活性（NRa）有上升趋势，但王红丽等[5]则认为，NR基因的表达量在不同供氮水平间并无明显差异。何文高[6]研究表明，提高施氮量对烟叶中谷氨酰胺合成酶活性（GSa）起到促进作用;曾孝敏[7]的研究表明，随着施氮量的增加，谷氨酸合成酶GOGATa增加，ANDREA等[8]研究认为，谷氨酰胺或天冬酰胺的体内积累对NR基因表达有负调控作用。由此……