ABSTRACT

This article studies the effect and mechanism of Si on drought and salt tolerance of Glycyrrhiza uralensis by focusing on the pathways of proline metabolism and nitrogen assimilation. G. uralensis was analysed under control, 70 mM NaCl, 15% PEG-6000 and 70 mM NaCl+15% PEG-6000 with or without Si. The results showed that Si increased P5Cs and δ-OAT activities by 16.29% and 5.85% under drought-salt stress, respectively. Si increased PDH by 28.14% under salt stress and increased proline by 27.6% and 33.0% under drought and drought-salt stresses in proline metabolism. In addition, Si increased NO₃⁻ by 36.9%, 42.63% and 44.07% under drought, salt and drought-salt stresses, respectively, increased GOGAT by 50.9% under salt stress, increased GDH by 34.78% and 25.44% under salt and drought-salt stresses in the process of N assimilation. Moreover, Si decreased H₂O₂ and MDA contents by 15.27%, 15.57%, 25.18% and 43.05%, 7.59%, 21.44% under drought, salt and drought-salt stresses, respectively. In sum, Si could increase the proline content by increasing P5Cs activity; meanwhile, Si also regulated the synthesis pathway of proline by improving N assimilation. Thus, the tolerance of G. uralensis to drought-salt stress was further enhanced by eliminating excessive ROS and reducing lipid peroxidation impairment.

摘要

本文通过脯氨酸代谢和氮同化途径研究Si对甘草耐旱耐盐的影响及其机制。G. uralensis在对照、70 mM NaCl、15% PEG-6000 和 70 mM NaCl+15% PEG-6000（含或不含硅）下进行分析。结果表明，Si在干旱盐胁迫下分别使P5Cs和δ-OAT活性提高了16.29%和5.85%。在脯氨酸代谢中，Si在盐胁迫下使PDH增加28.14%，在干旱和干旱-盐胁迫下使脯氨酸增加27.6%和33.0%。此外，Si增加了NO ₃ ^-N 过程中干旱、盐分和旱盐胁迫下分别增加 36.9%、42.63% 和 44.07%，盐胁迫下 GOGAT 增加 50.9%，盐和旱盐胁迫下 GDH 增加 34.78% 和 25.44%同化。此外，在干旱、盐分和干旱盐胁迫下，Si分别使H ₂ O ₂和MDA含量降低了15.27%、15.57%、25.18%和43.05%、7.59%、21.44%。总之，Si可以通过增加P5Cs活性来增加脯氨酸含量；同时，Si还通过改善N同化来调节脯氨酸的合成途径。因此，通过消除过量的 ROS 和减少脂质过氧化损伤，G. uralensis对干旱盐胁迫的耐受性得到进一步增强。