%0 Journal Article
%T 外源24-表油菜素内酯对低氧胁迫下黄瓜幼苗氮代谢的影响
%A 马月花
%A 郭世荣
%A 杜南山
%A 山溪
%A 孙锦
%A 王磊
%A 王颖
%A 束胜
%J 南京农业大学学报
%D 2015
%R 10.7685/j.issn.1000-2030.2015.04.003
%X [目的]本文的目的是研究外源24-表油菜素内酯(EBR)对低氧胁迫植株氮代谢的影响。[方法]以低氧耐性较弱的‘中农6号’黄瓜品种为材料,采用营养液通N2形成低氧逆境的方法,深入探讨了EBR对低氧胁迫下植株叶片和根系中与氮代谢相关的酶活性的影响。[结果]低氧处理显著降低了植株叶片的总氮含量,EBR使胁迫植株叶片总氮积累恢复至对照水平。低氧处理后,硝态氮含量在叶片中增加而在根系中降低,铵态氮的变化趋势与硝态氮相反,而EBR显著促进了胁迫植株根系的铵态氮积累。低氧胁迫下,植株根系硝酸还原酶(NR)和谷氨酰胺合成酶(GS)活性升高,随后恢复至对照水平,而谷氨酸合成酶(GOGAT)活性显著低于对照。叶片NR活性受到低氧抑制,亚硝酸还原酶(NiR)、GOGAT、氧化型谷氨酸脱氢酶(NAD+-GDH)活性则先升高,随后降低;叶片还原型谷氨酸脱氢酶(NADH-GDH)活性也受到低氧促进,至处理末期时显著高于对照植株。EBR显著提高了胁迫植株根系的NR活性及叶片的NiR、NAD+-GDH活性。[结论]黄瓜植株通过增强硝酸还原,加强氮代谢缓解低氧胁迫伤害;EBR通过增强根系NR活性及叶片NAD+-GDH活性,提高了植株的低氧耐性。</br>[Objectives]This paper was to investigate the effect of exogenous 24-epibrassinolide on nitrogen metabolism of cucumber seedlings under hypoxia stress. [Methods]A hypoxia-sensitive cucumber genotype(Cucumis sativus‘Zhongnong 6’)was used and we investigated the effect of EBR on activity of key enzymes involved in nitrogen assimilation of plants under hypoxia. [Results]Total N content of leaves was decreased remarkably under hypoxia while EBR restored it to the control level. NO-3 content was increased in leaf but reduced in root. The change of NH+4 content was contrary to that of NO-3. EBR improved NH+4 accumulation in root under hypoxia stress. The activity of root nitrate reductase(NR)and glutamine synthetase(GS)was increased at the beginning of the stress,but recovered to that of the control level after 9 d hypoxia. While glutamate synthase(GOGAT)activity was reduced significantly at the end of the stress. Under hypoxia,activity of leaf NR was inhibited greatly,while nitrite reductase(NiR),GOGAT and oxidized glutamate dehydrogenase(NAD+-GDH)activity showed a trend of increasing-decreasing with the prolongation of the stress. After 9 d hypoxia stress,activity of leaf reduced glutamate dehydrogenase(NADH-GDH)was raised significantly. EBR greatly improved activity of root NR,leaf NiR and NAD+-GDH of the plants under hypoxia. [Conclusions]The cucumber plants acclimated to hypoxia by improving nitrate reduction and nitrogen metabolism. EBR protected the plants from oxygen limitation by accelerating activity of root NR and leaf NAD+-GDH
%K 黄瓜
%K 低氧胁迫
%K 24-表油菜素内酯
%K 氮代谢&lt
%K /br&gt
%K cucumber
%K hypoxia stress
%K 24-epibrassinolide
%K nitrogen assimilation
%U http://nauxb.njau.edu.cn/oa/darticle.aspx?type=view&id=201504003