外源H_(2)O_(2)对不同亚种水稻种子萌发及幼苗生长的影响

Effect of exogenous H_(2)O_(2) on seed germination and seedling growth of different rice subspecies

本研究以籼稻(Oryza sativa subsp.indica)‘华占’、‘9311’以及粳稻(O.sativa subsp.japonica)‘越光’、‘中华11’为材料,探讨外源过氧化氢(H_(2)O_(2))对两个亚种种子萌发和幼苗发育的影响。结果表明:质量分数为0.1%的H_(2)O_(2)对4个品种种子萌发具有促进作用,对籼稻种子萌发的促进作用尤为显著;水稻幼苗经H_(2)O_(2)处理后生长受到明显抑制,叶片中过氧化物酶(POD)和过氧化氢酶(CAT)活性下降,丙二醛(MDA)和内源H_(2)O_(2)含量升高,且粳稻中MDA含量变化较籼稻显著,表明H_(2)O_(2)对粳稻细胞质膜的氧化损伤更严重;6个抗氧化酶基因在幼苗叶片中表达下调,过氧化氢酶基因(CATA)在粳稻中下调更明显,谷胱甘肽-S-转移酶基因(GSTU36)在籼稻中下调更明显。以上结果表明,不同品种水稻种子萌发和生长过程中对H_(2)O_(2)的敏感性不同,籼稻受外源H_(2)O_(2)影响较粳稻明显;在响应环境氧化胁迫时,籼、粳稻幼苗的抗氧化酶基因表达也存在差异性。

Four rice(Oryza sativa)varieties(‘Huazhan’,‘9311’,‘Koshihikari’and‘Zhonghua 11’)from two subspecies(indica and japonica)were used to investigate the effect of exogenous hydrogen peroxide(H_(2)O_(2))on seed germination and seedling growth in this study.The seed germination was promoted by H_(2)O_(2) with mass fraction of 0.1%,especially in indica rice.After H_(2)O_(2) treatment,the activities of peroxidase and catalase declined,while the contents of malondialdehyde(MDA)and endogenous H_(2)O_(2) increased in seedling leaves.There was distinct change of MDA content in japonica rice,indicating that more serious oxidative membrane damage was caused than that in indica rice by H_(2)O_(2).In addition,six antioxidant enzyme genes were down-regulated,among which catalase(CATA)and glutathione S-transferase(GSTU36)were more significantly in leaves of japonica and indica subspecies,respectively.These results suggest that different rice varieties have different sensitivity to H_(2)O_(2),and indica rice was more affected by exogenous H_(2)O_(2) than japonica rice.Moreover,the gene expression of antioxidant enzymes was also different in response to environmental oxidative stress in indica and japonica rice seedlings.