不同光强下盐胁迫对桑树幼苗叶片活性氧和叶绿素荧光特性的影响  

Effects of salt stress with different light intensity on active oxygen and chlorophyll fluorescence characteristics in leaves of Moros alba L seedlings

作　　者：逄好胜 张会慧[1] 田野[1] 敖红[1] 孙广玉[1] 

机构地区：[1]东北林业大学生命科学学院,黑龙江哈尔滨150040

出　　处：《中南林业科技大学学报》2014年第8期42-47,共6页Journal of Central South University of Forestry & Technology

基　　金：国家科技支撑项目(2011BAD08B02-3);国家自然科学基金(30771746;31070307);黑龙江省自然科学基金重点项目(ZD201105)共同资助

摘　　要：以桑树(Morus alba L.)为试验材料,分别研究了200、500和1 000μmol·m-2 s-1光强下,不同浓度盐胁迫对桑树幼苗叶片活性氧(ROS)代谢和叶绿素荧光参数的影响。结果表明:桑树幼苗叶片的ROS代谢和叶绿素荧光特性明显受到光强的影响。200μmol·m-2 s-1和500μmol·m-2 s-1下,超氧化物歧化酶(SOD)和抗坏血酸过氧化物酶(APX)有效降低了桑树幼苗叶片中的超氧阴离子(O2·-)和H2O2,且叶绿素荧光参数也没有发生明显变化,因此,弱光下桑树幼苗叶片抗氧化系统功能的增强在防止盐胁迫诱导的PSⅡ光抑制方面发挥了重要的作用。1 000μmol·m-2 s-1下,随着盐浓度的增加,桑树幼苗叶片O2·-大量产生,相应SOD活性增强,SOD的歧化作用导致了H2O2含量大量增加,同时在强氧化胁迫下,叶绿体内清除H2O2的APX活性却受到抑制,叶绿体内过量的H2O2可能破坏了电子传递链上的电子传递,并且PSⅡ发生了明显的光抑制。因此强光是引起盐胁迫下桑树幼苗叶片PSⅡ光抑制的重要原因之一,而强光引起盐胁迫下PSⅡ光抑制与ROS的代谢紊乱有关。By taking the seedlings of Morus alba L as the tested materials,the effects of the stresses of different concentration salt on reactive oxygen species（ROS） and chlorophyll fluorescence characteristics under different light intensities（200,500 and 1000 μmol·m-2s-1） were studied. The superoxide anion（O2·-） and H2O2 in leaves of mulberry seedlings were obviously decreased by superoxide dismutase（SOD） and ascorbate peroxidase（APX）,and the chlorophyll fluorescence parameters did not change obviously under 200 and 500 μmol·m-2s-1; therefore,the enhancement of antioxidant system function in leaves of mulberry seedlings played an important effect on preventing salt-induced of PS Ⅱ photoinhibition under weak light; As the increase of salt concentration,the O2·-contents abundantly produced,and the correspondingly SOD activities enhanced under 1000 μmol·m-2s-1; the dismutation of SOD led to H2O2 content increased significantly; meanwhile,APX activities which were mainly responsible for eliminating H2O2 were inhibited in chloroplasts under strong oxidative stress,the excessive H2O2 in chloroplasts possible damaged electron transports in the electron transport chain,and led to obvious PS Ⅱ photoinhibitions; hence,the high light was an important cause of PS Ⅱ photoinhibition in leaves of mulberry seedlings inducing by salt stress; however,PS Ⅱ photoinhibition caused by high light under salt stress were related to the metabolic disturbance of ROS.

关 键 词：桑树 光强 盐胁迫 活性氧 叶绿素荧光 

分 类 号：S718.43[农业科学—林学]