葎草幼苗光合生理特性对铬胁迫的响应  

Physiological and ecophysiological responses of Humulus scandens seedlings to chromium stress

作　　者：王碧霞[1] 胥晓[1] 李霄锋 

机构地区：[1]西华师范大学生命科学学院西南野生动植物资源保护教育部重点实验室,四川南充637009 [2]张家口市农业环境与农产品质量管理站,河北张家口075000

出　　处：《草业学报》2014年第4期181-188,共8页Acta Prataculturae Sinica

基　　金：四川省教育厅项目(12ZB142);西华师范大学创新团队资助

摘　　要：以葎草幼苗为对象,采用盆栽法研究不同铬浓度（Cr^3＋）（分别为0,50,200,300,500mmol/L）下葎草幼苗叶片光合生理特性的变化。结果表明,1）在低浓度（50mmol/L）Cr^3＋胁迫下,植株的净光合速率（Pn）、瞬时水分利用率（WUEi）显著高于对照,而气孔导度（Gs）、蒸腾速率（Tr）、气孔限制值（Ls）、胞间CO2浓度（Ci）及叶绿素含量与对照无显著差异。2）在中浓度（200-300mmol/L）Cr^3＋胁迫下,各光合参数及叶绿素含量呈下降趋势,且光下最小荧光（Fo′）、光下最大荧光（Fm′）、初始荧光（Fo）、最大荧光（Fm）、可变荧光（Fv）、PSⅡ的潜在活性（Fv/Fo）、最大光化学量子产量（Fv/Fm）和光化学淬灭（qP）逐渐减小,但Ls和WUEi随胁迫浓度的加重呈先升后降的趋势,Ci呈先降后升的变化,而ETR和丙二醛（MDA）含量则呈上升趋势,此时非光化学淬灭（qN）的变化没有规律。3）在高浓度（500mmol/L）Cr^3＋胁迫下,Pn、Tr、Ls、WUEi、MDA含量、叶绿素含量及qN均下降,Ci上升,且Fo′、Fm′、Fo、Fm、Fv、Fv/Fo、Fv/Fm和qP也显著增加。因此,低浓度Cr^3＋在一定程度上促进葎草幼苗生长,但随着Cr^3＋浓度增加,植株的气体交换参数、MDA含量、叶绿素含量及叶绿素荧光参数等光合生理特性具有显著不利影响,尤其是在高浓度Cr^3＋胁迫下,植株的生长受到严重抑制。The ecophysiological characteristics and photosynthesis of Humulus scandens seedlings under chromium stress（0,50,200,300,and 500mmol/L Cr^3＋）were studied.Under 50mmol/L stress,the net photosynthetic rate（Pn）and instant water use efficiency（WUE）increased significantly compared with the CK butstomatal conductance（Gs）,transpiration rate（Tr）,stomatal limitation（Ls）,intercellular CO2concentration（Ci）and chlorophyll contents were not significantly different.Under 200-300mmol/L stress,actual maximal fluorescence（Fm′）,actual minimum fluorescence（Fo′）,dark fluorescence yield（Fo）,maximal fluorescence yield（Fm）,variable fluorescence（Fv）,potential activity of PSⅡ（Fv/Fo）,maximum quantum yield of PSⅡ（Fv/Fm）and proportion yield of PSⅡ（qP）gradually decreased with an increase of Cr^3＋stress,while Lsand WUEiinitially increased but then decreased,whereas Ciinitially decreased but then increased.The opposite side of electron transport rate（ETR）and malonaldehyde（MDA）showed a tendency to increase,while the coefficient of non-photochemical quenching（qN）showed irregular changes.In particular,the Pn,Tr,Ls,WUEi,content of MDA and qNdeclined significantly in 500mmol/L Cr^3＋stress,but the Ciand other chlorophyll fluorescence parameters suddenly increased.In summer,there was a clear difference of gas change,content of MDA and chlorophyll and chlorophyll fluorescence parameters.Although some physiological indexes declined in the H.scandens seedlings with increasing Cr^3＋stress,but showed a positive response,keep certain photosynthesis under high Cr^3＋stress,and its tolerance to Cr^3＋stress was the strongest.

关 键 词：铬胁迫 葎草 气体交换 叶绿素含量 叶绿素荧光参数 

分 类 号：Q945.78[生物学—植物学]