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草业学报 ›› 2021, Vol. 30 ›› Issue (9): 86-96.DOI: 10.11686/cyxb2020322

• 研究论文 • 上一篇    下一篇

一氧化氮对干旱胁迫下紫花苜蓿氮代谢的影响

赵颖1,2,3(), 辛夏青1(), 魏小红1,2,3()   

  1. 1.甘肃农业大学生命科学技术学院,甘肃 兰州 730070
    2.甘肃省作物遗传改良与种质创新重点实验室,甘肃 兰州 730070
    3.甘肃省干旱生境作物学重点实验室,甘肃 兰州 730070
  • 收稿日期:2020-07-07 修回日期:2020-08-25 出版日期:2021-08-30 发布日期:2021-08-30
  • 通讯作者: 魏小红
  • 作者简介:Corresponding author. E-mail: weixh@gsau.edu.cn
    赵颖(1991-),女,宁夏永宁人,博士。E-mail:zhaoy@gsau.edu.cn
    辛夏青(1992-),女,山西左云人,硕士。E-mail: xinxiaqing4@163.com第一联系人:共同第一作者 These authors contributed equally to this work.
  • 基金资助:
    国家自然科学基金项目(31560663)

Effects of nitric oxide on nitrogen metabolism in alfalfa under drought stress

Ying ZHAO1,2,3(), Xia-qing XIN1(), Xiao-hong WEI1,2,3()   

  1. 1.College of Life Science and Technology,Gansu Agriculture University,Lanzhou 730070,China
    2.Gansu Key Laboratory of Crop Improvement & Germplasm Enhancement,Lanzhou 730070,China
    3.Gansu Provincial Key Laboratory of Aridland Crop Science,Lanzhou 730070,China
  • Received:2020-07-07 Revised:2020-08-25 Online:2021-08-30 Published:2021-08-30
  • Contact: Xiao-hong WEI

摘要:

为揭示NO对渗透胁迫下紫花苜蓿含氮化合物及氮代谢过程的调控机制,以紫花苜蓿为材料,通过外源施加NO供体硝普钠(SNP)和NO清除剂(c-PTIO)对紫花苜蓿种子及幼苗进行处理,研究NO在PEG模拟的渗透胁迫下紫花苜蓿氮类化合物含量及氮代谢关键酶活性变化规律中的影响。结果表明:与PEG处理相比,外施0.1 mmol·L-1 SNP,紫花苜蓿萌发期及幼苗期可溶性蛋白含量分别平均提高了 16.91%和8.87%,游离氨基酸含量平均降低14.92%和0.68%;硝酸还原酶(NR)、谷氨酰胺合成酶(GS)及谷氨酸合成酶(GOGAT)活性在萌发期分别提高了23.85%,47.87%,60.06%,在幼苗期分别提高了16.31%,23.56%,72.89%;而萌发期和幼苗期谷氨酸脱氢酶(GDH)活性分别降低了35.89%和33.35%。PEG胁迫下添加c-PTIO加剧了PEG胁迫对紫花苜蓿含氮物质积累的抑制,对NR,GS,GOGAT活性的影响差异不显著,GDH活性在萌发期及幼苗期分别平均升高了18.26%和4.62%。由此说明,外源NO通过调节氮代谢关键酶活性促进PEG胁迫下紫花苜蓿氮素向蛋白质合成的方向转运积累,提高紫花苜蓿抗旱性。

关键词: 紫花苜蓿, 一氧化氮, 干旱胁迫, 氮代谢

Abstract:

This experiment investigated the regulatory effects of nitric oxide on nitrogen compounds and nitrogen metabolism in alfalfa (Medicago sativa) under osmotic stress. External applications of NO donor sodium nitroprusside (SNP) and an NO scavenger (c-PTIO) to alfalfa seeds and seedlings were used to manipulate and study the behavior of endogenous NO-regulated nitrogenous substances and enzymes involved in nitrogen metabolism in alfalfa under PEG-induced simulated drought stress. It was found that, compared with PEG treatment, exogenous application of 0.1 mmol·L-1 SNP increased the concentration of soluble proteins in the germination and seedling stages by an average of 16.91% and 8.87%, respectively, and decreased free amino acid concentration by an average of 14.92% and 0.68%, respectively. The activities of nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT) were increased by up to 23.85%, 47.87%, and 60.06%, respectively, during the germination period, and by up to 16.31%, 23.56%, 72.89%, respectively, in seedlings. The activity of glutamate dehydrogenase (GDH) was decreased by up to 35.89% during germination and up to 33.35% in seedlings. The addition of c-PTIO under PEG stress exacerbated the inhibition effect on nitrogenous substances. The NO scavenger c-PTIO effects on NR, GS and GOGAT activities were not significant, while the activity of GDH was increased by an average of 18.26% and 4.62% during germination and in seedlings, respectively. Hence, the data indicate that NO promotes alfalfa nitrogen metabolism under PEG stress by regulating the activity of key enzymes in nitrogen metabolism, thus promoting the transport and accumulation of nitrogen for protein synthesis.

Key words: Medicago sativa, nitric oxide, PEG stress, nitrogen metabolism