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| Cd胁迫下外源谷胱甘肽对紫花苜蓿氮代谢及Cd累积特征的影响 |
| Effects of exogenous glutathione on nitrogen metabolism and cadmium accumulation in Medicago sativa under cadmium stress |
| 投稿时间：2022-03-08 |
| DOI：10.13254/j.jare.2022.0108 |
| 中文关键词: 紫花苜蓿，Cd胁迫，谷胱甘肽，氮代谢，Cd累积特征 |
| 英文关键词: Medicago sativa, Cd stress, glutathione, nitrogen metabolism, Cd accumulation characteristics |
| 基金项目:国家自然科学基金项目 （31860112） |
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| 中文摘要: |
| 为研究镉（Cd）胁迫下外源谷胱甘肽（GSH）对紫花苜蓿（Medicago sativa）氮代谢及Cd累积特征的影响，以4种紫花苜蓿为植物材料，设置对照、Cd处理和混合处理（Cd+GSH）开展水培试验。结果表明，Cd胁迫影响紫花苜蓿氮代谢，谷氨酸合成酶活性较对照处理最高降低43.79%。Cd胁迫下喷施GSH后，总氮、氮代谢关键酶活性、游离氨基酸和可溶性蛋白较Cd处理均有不同程度地变化，其中谷氨酸合成酶活性较Cd处理最高增加79.05%。外源GSH影响紫花苜蓿体内Cd的化学形态与亚细胞分布：施加GSH后盐酸提取态占比较Cd处理最高增加14.81个百分点；外源GSH处理下液泡中的Cd含量占比较Cd处理最高上升11.91个百分点； GSH处理还能显著提高紫花苜蓿植物螯合肽（PCs）含量，有效阻止Cd以游离态的形式进入细胞器。研究表明，Cd胁迫下外源GSH可提高紫花苜蓿硝酸还原酶等氮代谢关键酶活性，维持氮代谢正常进行；外源GSH可能通过提高PCs的合成水平和减轻Cd毒害，间接对氮代谢进行调控。 |
| 英文摘要: |
| To study the effects of exogenous glutathione（GSH）on nitrogen metabolism and cadmium（Cd）accumulation in Medicago sativa under Cd stress, four Medicago sativa varieties were used as plant materials. The treatments were control, Cd, and mixed（Cd+GSH） . The results showed that Cd stress had higher impact on the four Medicago sativa varieties for total nitrogen content and activity of major nitrogen metabolism enzymes with up to 43.79% reduction in glutamate synthase activity. After spraying GSH under Cd stress, total nitrogen, key enzyme activities of nitrogen metabolism, free amino acids, and soluble protein all changed to different degrees compared with Cd treatment, with the highest increase of 79.05% in glutamate synthase compared with Cd treatment. Exogenous GSH affected the chemical form and subcellular distribution of Cd in Medicago sativa, with the highest increase of 14.81 percentage points in the hydrochloride extracted state after GSH application compared with the Cd treatment. The proportion of Cd content in vesicles under exogenous GSH treatment increased by 11.91 percentage points compared with the Cd treatment. GSH treatment also significantly increased the content of phytochelatin in Medicago sativa plants, effectively preventing Cd from entering the organelle in its free form. This study shows that exogenous GSH under Cd stress can increase the activity of key enzymes of nitrogen metabolism such as nitrate reductase in Medicago sativa and maintain normal nitrogen metabolism. Cd toxicity can be mitigated by compartmentalisation. Exogenous GSH may indirectly regulate nitrogen metabolism in this way. |
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