中文摘要：

以拟南芥野生型（WT）和H2S体内生成的关键酶编码基因LCD敲除突变体为实验材料，研究了内源H2S在干旱胁迫下对种子萌发和幼苗生长过程中抗氧化能力的影响．结果表明：lcd突变体与wT相比，干旱胁迫下种子的萌发受到显著抑制，萌发率下降约40％；幼苗体内的MDA含量显著增加，达到WT的1．56倍，差异极显著；同时幼苗体内的H2O2明显增加．正常条件下，lcd与WT相比各抗氧化酶活性均没有显著差异；干旱胁迫后，lcd的POD、CAT、SOD和APX的活性分别升高2．11、1．48、2．22和1．37倍，差异极显著；且与胁迫后的WT相比，这些指标也表现出显著性增高．以上结果表明内源HzS作为信号分子通过对抗氧化系统的调节，影响拟南芥种子萌发和幼苗生长发育．

英文摘要：

Arabidopsis thaliana wild-type （WT） and knockdown mutant of LCD, a L-cysteine desulfhydrase encoding gene to catalyze the reaction to produce HzS in vivo,were used as experimental materials. The re- sult indicated the effect of endogenous H2 S on seed germination and seedling growth under drought stress. Moreover,the results showed that the seed germination was inhibited significantly in lcd compared to WT under drought stress,with germination rate decreasing by about 40%;the MDA content of the seedlings was more 1.56 times in lcd than that in WT with extremely significant difference; at the same time the H2 O2 content also increased significantly. Under the normal conditions, all antioxidant enzyme activities in lcd and WT showed similar values. The POD,CAT, SOD and APX activity enhanced about 2. 11,1.48, 2.22 and 1.37 folds in lcd after drought stress,respectively,which showed significant difference compared with that in WT. All together,these results suggest that endogenous H2S as gasotransmitter can affect the seed germination and seedling development through regulation of antioxidant system in A. thaliana.