Journal of Integrative Agriculture ›› 2021, Vol. 20 ›› Issue (5): 1216-1228.DOI: 10.1016/S2095-3119(20)63216-6

所属专题: 麦类耕作栽培合辑Triticeae Crops Physiology · Biochemistry · Cultivation · Tillage

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  • 收稿日期:2019-11-11 出版日期:2021-05-01 发布日期:2021-04-12

Changes of oxidative metabolism in the roots of wheat (Triticum aestivum L.) seedlings in response to elevated ammonium concentrations

LIU Yang1, 2*, LI Yu-xiang2*, LI Yi-xiang1, TIAN Zhong-wei1, HU Jin-ling1, Steve ADKINS3, DAI Ting-bo1   

  1. 1 Key Laboratory of Crop Physiology and Ecology in Southern China/College of Agriculture, Nanjing Agricultural University, Nanjing 210095, P.R.China
    2 College of Agriculture, Shihezi University, Shihezi 823003, P.R.China
    3 School of Agriculture and Food Sciences, the University of Queensland, Gatton QLD 4343, Australia
  • Received:2019-11-11 Online:2021-05-01 Published:2021-04-12
  • Contact: Correspondence DAI Ting-bo, Tel: +86-25-84396466, E-mail: tingbod@njau.edu.cn
  • About author:* These authors contributed equally to this study.
  • Supported by:
    This study was funded by a project of the National Natural Science Foundation of China (31471443), the Jiangsu Collaborative Innovation Center for Modern Crop Production, China (JCIC-MCP) and the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (PAPD).

摘要:

试验采用温室水培的方式,以豫麦49(高铵迟钝型)和鲁麦15(高铵敏感型)为材料,设置了5.0 mM NH4+-N(EAC)和NO3--N(CON)两个处理,研究了小麦幼苗根系氧化代谢对高铵胁迫的响应机制。结果表明,高铵胁迫下,两个小麦品种根系生长显著降低,其中鲁麦15降低程度高于豫麦49。高铵胁迫增加了两个小麦品种根系单脱氢抗坏血酸还原酶活性和脱氢抗坏血酸还原酶活性,但降低了处理12天后的根系抗坏血酸(ASA)含量和GDP-甘露糖焦磷酸酶(GMPase)活性,其中鲁麦15根系ASA含量和GMPase活性分别降低了62.0和71.4%,豫麦49根系ASA含量和GMPase活性分别降低了38.8和62.2%,说明高铵胁迫提高了ASA再生,但减少了ASA合成。此外,EAC增加了两个小麦品种根系DHA/ASA,活性氧(ROS)含量,丙二醛含量和抗氧化物酶活性。与豫麦49相比,鲁麦15根系中ROS含量和可溶性糖含量相对增加较多,而抗氧化物酶活性增加较少,说明鲁麦15根系氧化代谢紊乱更严重。结果表明,高铵胁迫下,GMPase活性降低导致ASA生物合成的减少可能是ROS过量积累和氧化还原失衡的原因之一,进而抑制小麦幼苗根系生长。与高铵敏感型品种鲁麦15相比,豫麦49具有较强的氧化胁迫保护能力,维持较低水平DHA/ASA,进而保持较好的氧化还原平衡状态,因此更耐高铵。


Abstract:

To elucidate the response of oxidative metabolism, triggered by elevated ammonium (NH4+) concentrations, on root growth of wheat seedlings, Yumai 49 (NH4+-tolerant) and Lumai 15 (NH4+-sensitive) cultivars were supplied with either 5.0 mmol L–1 NH4+-N (EAC) or 5.0 mmol L–1 NO3-N (CON) under hydroponic conditions.  Root growth in both cultivars was significantly reduced under EAC, and the negative effect was greater in Lumai 15.  EAC enhanced the activities of monodehydroascorbate reductase and dehydroascorbate reductase in the roots of both cultivars, while it decreased ascorbic acid (ASA) content and GDP-mannose pyrophosphorylase (GMPase) activity at the 12th day after treatment in Lumai 15 by 62.0 and 71.4%; and in Yumai 49 by 38.8 and 62.2%, respectively, indicating that the regeneration of ASA was increased, but the biosynthesis of ASA was reduced under EAC treatment.  Moreover, EAC increased DHA/ASA, reactive oxygen species (ROS), and malondialdehyde contents, as well as antioxidant enzyme activities in the roots of both cultivars.  Relatively greater increases in ROS and soluble sugar, and lower antioxidant enzyme activities in Lumai 15 indicate severe disruption of oxidative metabolism when compared to Yumai 49.  Results reveal that the reduction of ASA biosynthesis via decreased GMPase activity under the EAC condition probably acts as a trigger for accumulated ROS and imbalanced redox status, resulting in root growth inhibition during wheat seedling growth stage.  Yumai 49, being an NH4+-tolerant cultivar, had the stronger capacity to protect itself from oxidative stress, which allowed it to retain a lower DHA to ASA ratio by maintaining a better redox homeostasis than could be maintained in the NH4+-sensitive cultivar Lumai 15.

Key words: elevated ammonium concentrations ,  oxidative metabolism ,  redox homeostasis ,  root morphology ,  wheat