硝普钠对低温胁迫下枇杷幼果线粒体AsA-GSH循环代谢的影响

Effects of Exogenous Sodium Nitroprusside on AsA-GSH Circulation Metabolism in Mitochondria of Young Loquat Fruits under Low Temperature Stress

探讨外源一氧化氮供体硝普钠(sodium nitroprusside,SNP)处理对低温胁迫下"早钟6号"枇杷(Eriobotrya japonica Lindl.cv.Zaozhong No.6)幼果线粒体抗氧化系统的影响。以不同浓度的SNP处理"早钟6号"枇杷幼果后再经-3℃低温胁迫处理,测定幼果线粒体的抗氧化物质和抗氧化酶活性的变化。结果表明,低温胁迫下,经0.2和0.5 mmol/L SNP处理的枇杷幼果线粒体过氧化氢(H2O2)和丙二醛(MDA)含量均低于对照(CK),而还原型谷胱甘肽(GSH)和抗坏血酸(AsA)含量以及抗坏血酸过氧化物酶(APX,EC 1.11.1.11)、谷胱甘肽还原酶(GR,EC 1.6.4.2)、脱氢抗坏血酸还原酶(DHAR,EC 1.8.5.1)和单脱氢抗坏血酸还原酶(MDHAR,EC 1.6.5.4)活性均高于CK,但采用1.0 mmol/L较高浓度的SNP处理对提高枇杷幼果抗氧化能力的作用不明显。适当的外源NO处理可提高枇杷幼果线粒体GSH和AsA抗氧化剂的含量以及APX、GR、DHAR和MDHAR酶的活性,降低H2O2和MDA含量,减轻细胞的氧化损伤,增强枇杷幼果在低温胁迫下的抗寒能力。

The effects of exogenous nitric oxide donor SNP （sodium nitroprusside） on antioxidant systems in young loquat （Eriobotrya japonica Lindl. cv. Zaozhong No. 6） fruit mitochondria under low temperature stress were investigated in this study. The antioxidant content and antioxidant enzyme activity of mitochondrion of young loquat fruits were determined after pretreated with different concentrations of SNP and cold stress under -3 ℃. The results indicated that the concentrations of hydrogen peroxide （H202） and malondialdehyde （MDA） of young loquat fruits treated with 0.2 or 0.5 mmol/L SNP were lower than those in the CK while the content of reduced glutathione （GSH） and ascorbate （AsA） , the activities of ascorbate peroxidase （APX, EC 1.11.1.11）, glutathione reductase （GR, EC 1.6.4.2）, dehydroascorbate reductase （DHAR, EC 1.8.5.1） and monodehydroascorbate reductase （MDHAR, EC 1.6.5.4） were higher than those in the CK. However, the effect of higher concentrations of SNP （1.0 mmol/L） treatment on antioxidant capacity of young fruits was not obvious. Appropriate exogenous NO treatment enhanced the cold-resistant capacity of mitochondrion of young loquat fruits by raising the concentrations of GSH and AsA, the activities of APX, GR, DHAR and MDHAR, reducing the concentrations of H202 and MDA. And it reduced the damages that cells suffered from low temperature press, enhanced the cold-resistance capability of the young loquat fruits under low temperature stress.