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草业学报 ›› 2023, Vol. 32 ›› Issue (7): 175-187.DOI: 10.11686/cyxb2022352

• 研究论文 • 上一篇    

狗牙根叶与根氮代谢对不同干旱胁迫的响应机制

张一龙1(), 李雯1, 喻启坤1, 李培英1,2,3(), 孙宗玖1,2,3   

  1. 1.新疆农业大学草业学院,新疆 乌鲁木齐 830052
    2.新疆草地资源与生态自治区重点实验室,新疆 乌鲁木齐 830052
    3.西部干旱区草地资源与生态教育部重点实验室,新疆 乌鲁木齐 830052
  • 收稿日期:2022-08-31 修回日期:2022-09-19 出版日期:2023-07-20 发布日期:2023-05-26
  • 通讯作者: 李培英
  • 作者简介:E-mail: 823797457@qq.com
    张一龙(1997-),男,新疆阿勒泰人,在读硕士。E-mail: 871298780@qq.com
  • 基金资助:
    国家自然科学基金项目(31960362);新疆农业大学研究生创新项目(XJAUGRI2021022)

Nitrogen metabolism response mechanism to different drought stresses in leaves and roots of Cynodon dactylon

Yi-long ZHANG1(), Wen LI1, Qi-kun YU1, Pei-ying LI1,2,3(), Zong-jiu SUN1,2,3   

  1. 1.College of Grassland Science,Xinjiang Agricultural University,Urumqi 830052,China
    2.Key Laboratory of Grassland Resources and Ecology of Xinjiang,Urumqi 830052,China
    3.Key Laboratory of Grassland Resources and Ecology of Western Arid Region,Urumqi 830052,China
  • Received:2022-08-31 Revised:2022-09-19 Online:2023-07-20 Published:2023-05-26
  • Contact: Pei-ying LI

摘要:

干旱会影响植物氮代谢过程,从而制约其生长及品质。为了明确狗牙根在干旱胁迫下其叶与根氮代谢指标的变化,探讨狗牙根叶与根氮代谢对不同干旱胁迫的响应机制,筛选关键抗旱氮代谢指标,丰富狗牙根抗旱氮代谢理论,本试验将不同抗旱性狗牙根在不同干旱梯度处理下培养10 d,测定其叶及根有机氮化物(脯氨酸、可溶性蛋白、游离氨基酸)、无机氮化物(全氮、硝态氮、铵态氮)、氮代谢相关酶活性(硝酸还原酶、亚硝酸还原酶、谷氨酰胺合成酶、谷氨酸合成酶)等生理指标。结果表明:随着干旱胁迫加剧,各供试材料的叶及根全氮降低,有机氮化物增加,叶片硝态氮先降后升,根系硝态氮降低,叶、根铵态氮、氮代谢酶则呈先增后降趋势。抗旱材料在胁迫下因具有较高的氮代谢酶活性及无机氮化物含量,加速了氮代谢进程,致使抗旱材料叶、根的有机氮化物含量快速上升且显著高于敏旱材料。干旱下狗牙根通过对根系吸收的氮素进行转运再分配、同化,与其地上部分共同抵御干旱。冗余分析表明谷氨酸合成酶(GOGAT),谷氨酰胺合成酶(GS)与中度胁迫时抗旱材料叶、根的相关性较强,脯氨酸、游离氨基酸、可溶性蛋白与重度胁迫时抗旱材料有较强的相关性。通径分析得根系可溶性蛋白(决策系数为-0.739)、叶片(0.530)与根系游离氨基酸(0.498)与干旱下狗牙根抗旱性关联度高。本试验结果可丰富、补充狗牙根抗旱氮代谢响应研究,也可为其抗旱资源选育提供参考。

关键词: 狗牙根, 干旱胁迫, 氮代谢, 氮化物含量, 氮代谢酶活性

Abstract:

Drought will affect plant nitrogen metabolism, thereby seriously restricting plant growth and forage quality. In order to clarify the changes in nitrogen metabolism indexes of Cynodon dactylon leaves and roots under drought stress, this experiment explored the nitrogen metabolism response mechanism of C. dactylon strains with differing drought resistance to different levels of drought stress, and varieties were screened for the key traits. C. dactylon plants were grown for 10 days under different water gradient treatments, and physiological data such as organic nitrides (proline, soluble protein, free amino acid), inorganic nitrides (total nitrogen, nitrate nitrogen, ammonium nitrogen), and the activities of nitrogen metabolism related enzymes [nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthetase (GOGAT)] were collected for leaves and roots. It was found that with increased intensity of drought stress, total nitrogen of leaf and root decreased, organic nitride increased, the leaf nitrate nitrogen initially decreased and then increased, the root nitrate nitrogen decreased, and the ammonium nitrogen and nitrogen metabolic enzymes in leaves and roots initially increased and then decreased. Under moderate and severe stress, drought resistant materials accelerated the process of nitrogen metabolism due to their high nitrogen metabolism enzyme activity and inorganic nitride content, resulting in the rapid increase of organic nitride content in leaf and root of drought resistant strains to levels significantly higher than those of drought sensitive materials. Under drought, C. dactylon was able to largely overcome negative impacts on leaves by transporting, redistributing and utilising the nitrogen absorbed by the root. Redundancy analysis showed that GOGAT and GS were strongly associated with leaf and root drought resistance traits in drought resistant materials under moderate stress. Meanwhile, under severe stress, drought resistance was correlated proline, free amino acid and soluble protein levels. Path analysis showed that root soluble protein (decision coefficient -0.739), leaf (0.530) and root free amino acid (0.498) were highly correlated with drought resistance of C. dactylon under drought. The results of this experiment enhance understanding of drought resistance and related nitrogen metabolism responses of C. dactylon, and also provide reference for the breeding of drought resistant resources.

Key words: Cynodon dactylon, drought stress, nitrogen metabolism, nitride content, nitrogen metabolizing enzyme activity