硅对盐胁迫下黄瓜根系线粒体呼吸作用及脂质过氧化的影响

以黄瓜根系离体线粒体为研究对象,观察了盐胁迫对线粒体辅酶Q10(CoQ.10)、脂质过氧化物(LPO)、过氧化氢(H2O2)含量和线粒体呼吸功能及其有关酶的影响,以及盐胁迫下添加外源Si后这些指标的变化。试验设对照(CK)、盐胁迫(NaCl)、和盐胁迫加硅(NaCl+Si)。结果表明,盐胁迫下线粒体H2O2和丙二醛(MDA)的含量显著增加,线粒体膜流动性降低,CoQ10含量下降,与能量代谢相关的ATP酶及呼吸酶细胞色素c氧化酶(CCO)显著下降,引起线粒体膜损伤。加入外源Si后,线粒体H2O2和MDA的含量降低,膜流动性增加,CoQ10含量、ATP酶及细胞色素c氧化酶活力增加。表明Si可能通过促进线粒体ATPase与CCO活性的恢复,CoQ10含量的增加及减少氧自由基的损害而对线粒体产生保护作用,提高线粒体的氧化磷酸化及能量代谢,从而提高线粒体的呼吸作用。

Effects of Si on the mitochondria respiration and lipid peroxidation of cucumber (Cucumis sativus L.) roots under salt stress

Using K_2SiO_4(1.0 mmol/L) as Si exogenous supply resource examined the changes of Coenzyme Q10(CoQ10),lipid peroxidation(LPO),hydrogen peroxide(H_2O_2) and respiration in isolated mitochondria of cucumber (Cucumis sativus L.) roots under salt stress.The experiment consists of three treatments,namely: CK,NaCl,and NaCl Si.The results showed that NaCl stress increased H_2O_2 and malondialdehyde(MDA) contents in mitochondria,decreased membrane fluxion;reduced CoQ10 content,depressed activities of ATPase and cytochrome oxidase(CCO).Additional Si supplying for salt-stressed cucumber significantly decreased H_2O_2 and MDA content,inproved membrane fluxion,increased CoQ10 content,and promoted activities of ATPase and CCO.It indicated that additional Si supplying under salt stress could protect mitochondria by resuming the activities of ATPase and CCO,and increasing CoQ10 content,increase oxidative phosphorylation and energy metabolism,consequently mitochondria respiration increased.