In current study, we investigated the relationship between hydrogen sulfide (H2S) and nitric oxide (NO) in the regulation of ascorbate-glutathione (AsA-GSH) cycle in wheat seedlings by water stress. Findings showed that water stress significantly stimulated the production of H2S and NO, the transcript levels and activities of enzymes in AsA-GSH cycle, as well as malondialdehyde (MDA) production and electrolyte leakage, but significantly decreased AsA/DHA and GSH/GSSG. Meanwhile, water stress significantly decreased plant height and dry biomass. Except MDA and electrolyte leakage, above changes induced by water stress were reversed by H2S synthesis inhibitor aminooxyacetic acid (AOA) and NO synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME). However, AOA and L-NAME significantly enhanced MDA production and electrolyte leakage, which further decreased plant height and dry biomass of wheat seedlings under water stress. Application of exogenous H2S donor sodium hydrosulfide (NaHS) to AOA-treated plants and application of exogenous NO donor sodium nitroprusside (SNP) to L-NAME-treated plants reversed above effects of AOA and L-NAME, respectively. Application of L-NAME plus water stress significantly decreased NO production induced by water stress. However, application of L-NAME plus water stress had no obvious influence on H2S production induced by water stress, while application of AOA plus water stress significantly reduced the production of H2S and NO induced by water stress. Current findings suggested that H2S acted upstream of NO in the regulation of AsA-GSH cycle in wheat seedlings by water stress.

中文翻译：

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H2S 诱导 NO 参与水分胁迫对小麦幼苗 AsA-GSH 循环的调控

在目前的研究中，我们研究了硫化氢 (H2S) 和一氧化氮 (NO) 在水分胁迫对小麦幼苗抗坏血酸-谷胱甘肽 (AsA-GSH) 循环的调节中的关系。结果表明，水分胁迫显着刺激了 H2S 和 NO 的产生、AsA-GSH 循环中酶的转录水平和活性，以及​​丙二醛 (MDA) 的产生和电解质泄漏，但显着降低了 AsA/DHA 和 GSH/GSSG。同时，水分胁迫显着降低了植物高度和干生物量。除MDA和电解质泄漏外，水分胁迫引起的上述变化被H2S合成抑制剂氨基氧乙酸（AOA）和NO合成抑制剂NG-硝基-L-精氨酸甲酯（L-NAME）逆转。然而，AOA 和 L-NAME 显着增加了 MDA 的产生和电解质泄漏，这进一步降低了水分胁迫下小麦幼苗的株高和干生物量。外源 H2S 供体硫氢化钠 (NaHS) 应用于 AOA 处理的植物和外源 NO 供体硝普钠 (SNP) 应用于 L-NAME 处理的植物分别逆转了 AOA 和 L-NAME 的作用。L-NAME 和水分胁迫的应用显着降低了水分胁迫诱导的 NO 产生。而L-NAME加水分胁迫对水分胁迫诱导的H2S产生没有明显影响，而AOA加水分胁迫的应用则显着降低了水分胁迫诱导的H2S和NO的产生。目前的研究结果表明，H2S 作用于 NO 的上游，通过水分胁迫调节小麦幼苗的 AsA-GSH 循环。