以野生型拟南芥(Arabidopsis thaliana)及其突变体(atrbohD、atrbohF、atrbohD/F、atl-cdes、atd-cdes)和过表达株系(OEL-CDes、OED-CDes)为材料,利用药理学实验,结合分光光度法和激光共聚焦显微技术,探讨硫化氢(hydrogen sulfide,H2S)在干旱诱导的拟南芥气孔关闭中的作用及其与过氧化氢(hydrogen peroxide,H2O2)的关系.结果表明,H2S清除剂次牛磺酸(hypotaurine,HT)及合成抑制剂氨氧基乙酸(aminooxy acetic acid,AOA)、羟胺(hydroxylamine,NH2OH)和丙酮酸钾(potasium pyruvate,C3H3KO3)+氨水(ammonia,NH3)均可不同程度抑制干旱诱导的气孔关闭；干旱对OEL-CDes和OED-CDes植株气孔关闭的诱导作用明显,而atl-cdes和atd-cdes叶片气孔对干旱胁迫反应的敏感性下降；干旱胁迫能明显增加拟南芥保卫细胞中H2O2水平及叶片中H2S含量,提高D-/L-半胱氨酸脱巯基酶活性及基因表达量,而对突变体atrbohD、atrbohF和atrbohD/F没有显著影响.清除H2O2可减弱干旱胁迫对H2S含量和D-/L-半胱氨酸脱巯基酶活性的诱导效应.研究结果表明H2S位于H2O2下游参与干旱诱导拟南芥气孔关闭的信号转导过程.%Using the Arabidopsis thaliana wild-type; mutants atrbohD, atrbohF, atrbohD/F, atl-cdes, and atd-cdes; and D-/L-cysteine desulfhydrase overexpression plants, we investigated the roles of hydrogen sulfide (H2S) in drought-induced stomatal closure in A. thaliana. We used a pharmacological experiment combined with laser scanning confocal microscopy and spectrophotography. The H2S scavenger hypotaurine and H2S synthesis inhibitors aminooxy acetic acid, hydroxylamine, potasium pyruvate and ammonia all inhibited drought-induced stomatal closure. Drougnt-induced stomatal closure was greater in overexpression than wild-type plants, with the effect not obvious in atl-cdes and atd-cdes. Moreover, drought stress enhanced the level of hydrogen peroxide (H2O2) in guard cells and increased the content of H2S and the activity and expression of D-/L-cysteine desulfhydrase in leaves but had no significant effect in atrbohD, atrbohF, and atrbohD/F. The H2O2 scavenger decreased drought-induced H2S production and the activity of D-/L-cysteine desulfhydrase in leaves. H2S may function downstream of H2O2 in the signal transduction pathway of drought-induced stomatal closure in A. thaliana.
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