Key Laboratory of Molecular and Cytogenetics, College of Life Science and Technology, Harbin Normal University, Harbin, 150025, Heilongjiang Province, China.
Key Laboratory of Molecular and Cytogenetics, College of Life Science and Technology, Harbin Normal University, Harbin, 150025, Heilongjiang Province, China.
Plant Physiol Biochem. 2024 Mar;208:108475. doi: 10.1016/j.plaphy.2024.108475. Epub 2024 Feb 28.
Saline-alkali stress significantly affects the growth and yield of alfalfa (Medicago sativa L.). Organic acid secretion is crucial in alleviating abiotic stress-induced damage in plants. In this study, we evaluated the contents of the major organic acids secreted by the roots of tolerant (ZD) and sensitive (LYL) varieties of alfalfa under saline-alkali stress and investigated the effects of these organic acids on the growth, and physiological functions of alfalfa. Our results indicated that the oxalic acid (OA) content was the highest among the organic acids secreted from alfalfa roots under saline-alkali stress, and oxalic acid content was the most significantly different between the two varieties, ZD and LYL, compared to the contents of the other organic acids. Oxalic acid alleviated the inhibition of alfalfa growth caused by saline-alkali stress, improved photosynthetic characteristics, reduced the accumulation of reactive oxygen species, and increased the activity of antioxidant enzymes and content of osmoregulatory substances. Furthermore, oxalic acid resulted in significantly increased expression of genes involved in photosynthesis and antioxidant system in alfalfa under saline-alkali stress. This study revealed the effects of oxalic acid secreted by the root system on stress-related physiological processes, providing valuable insights into the functions of root secretions in plant saline-alkali resistance.
盐碱性胁迫显著影响紫花苜蓿（Medicago sativa L.）的生长和产量。有机酸分泌在缓解植物非生物胁迫损伤中至关重要。本研究评估了耐盐碱性（ZD）和敏感（LYL）苜蓿品种在盐碱性胁迫下根系分泌的主要有机酸含量，并研究了这些有机酸对苜蓿生长和生理功能的影响。结果表明，盐碱性胁迫下苜蓿根系分泌的有机酸中草酸（OA）含量最高，ZD 和 LYL 两个品种间草酸含量差异最显著，与其他有机酸含量相比差异极显著。草酸缓解了盐碱性胁迫对苜蓿生长的抑制作用，改善了光合特性，降低了活性氧的积累，提高了抗氧化酶的活性和渗透调节物质的含量。此外，草酸处理显著增加了盐碱性胁迫下苜蓿光合作用和抗氧化系统相关基因的表达。本研究揭示了根系分泌的草酸对胁迫相关生理过程的影响，为根系分泌物在植物耐盐碱性中的功能提供了有价值的见解。
