硅对过量锰胁迫下水稻根系抗氧化系统和膜脂质过氧化作用的调控机理  

Silicon-mediated antioxidant reactions and membrane lipid peroxidation in roots of rice(Oryza sativa L.) exposed to excess manganese

作　　者：李萍[1,2] 宋阿琳[1] 李兆君[1] 梁永超[1] 

机构地区：[1]中国农业科学院农业资源与农业区划研究所,北京100081 [2]山西农业大学农学院,太谷030801

出　　处：《环境科学学报》2011年第7期1542-1549,共8页Acta Scientiae Circumstantiae

基　　金：国家科技支撑计划(No.2006BAD02A15)~~

摘　　要：揭示Mn胁迫下Si对水稻根系抗氧化系统的影响机制,可为减轻水稻Mn毒害提供重要的理论依据和技术支持.因此,本研究通过水培试验,采用两个对Mn耐性不同的水稻品种,研究Si(1.5mmol·L-1)对Mn(2mmol·L-1)胁迫下水稻根系抗氧化系统的影响.结果表明,在Mn胁迫下,敏感品种新香优640(XXY)根系的超氧化物歧化酶(SOD)活性、抗坏血酸(AsA)和非蛋白巯基(NPT)含量显著增加,但过氧化物酶(CAT)和抗坏血酸过氧化物酶(APX)酶活性显著降低,谷胱甘肽(GSH)含量也显著降低,最终导致膜脂过氧化加剧,丙二醛(MDA)含量升高,质膜完整性遭到破坏,根系受到伤害.Mn胁迫下,耐性品种株两优99(ZLY)根系的GSH和AsA含量增加,但CAT酶活性和NPT含量降低,导致MDA含量升高,根系受到伤害.加Si后增强了水稻根系抗氧化系统活性,降低了MDA和过氧化氢(H2O2)含量,缓解了水稻根系受到的伤害.总体而言,Mn胁迫下,施Si处理可加强水稻根系抗氧化系统的防御能力,使根尖质膜保持完整,减轻膜脂质过氧化伤害,缓解根系受到的伤害,且这种缓解效应在敏感品种XXY根系中更为显著.The aim of the present work was to study the mechanism of the silicon-mediated antioxidant system in roots of rice grown under excess manganese（Mn） stress and Mn tolerance regulated by silicon（Si）.Two rice varieties that differ in Mn tolerance were cultured in nutrient solution to study the effects of Si（1.5 mmol · L-1） on antioxidant systems of rice roots under excess Mn stress（2 mmol · L-1）.For the Mn-sensitive cultivar（XXY）,excess Mn significantly increased the activities of superoxide dismutase（SOD）,the concentrations of ascorbate（AsA） and non-protein thiols（NPT）,while it significantly decreased the activities of catalase（CAT） and ascorbate peroxidase（APX） and the concentrations of glutathione（GSH）,thus leading to accumulation of high levels of malondialdehyde（MDA） in root tissues and destruction of plasma membrane integrity.However,excess Mn significantly increased the concentrations of GSH and AsA,but significantly decreased the activities of CAT and the concentrations of NPT,thus leading to accumulation of high level of MDA in the Mn-tolerant cultivar（ZLY）.The addition of Si significantly decreased the concentrations of MDA and H2O2 in Mn-stressed root tissues,thereby mitigating the damage.Under excess Mn stress,application of silicon enhances the antioxidant activities of rice roots,and reduces lipid peroxidation and damage to the integrity of the apical membrane,thereby enhancing rice resistance to manganese toxicity.This alleviative effect is more pronounced in Mn-sensitive rice（XXY） than in Mn-tolerant rice（ZLY）.

关 键 词：锰胁迫 硅 水稻根系 抗氧化系统 膜脂质过氧化 

分 类 号：X171.5[环境科学与工程—环境科学]