低温弱光胁迫对棉花幼苗叶绿素荧光特性及能量分配的影响  

Effects of Low Temperature and Weak Light Stress on Chlorophyll Fluorescence Characteristics and Energy Allocation in Cotton Seedlings

作　　者：武辉[1] 周艳飞[1] 侯丽丽[1] 范志超[1] 石俊毅[1] 阿丽艳.肉孜 张巨松[1] 

机构地区：[1]新疆农业大学农学院/教育部棉花工程研究中心,乌鲁木齐830052

出　　处：《新疆农业科学》2012年第3期393-399,共7页Xinjiang Agricultural Sciences

基　　金：国家"十一五"科技支撑项目(2009BADA4B01-3)

摘　　要：【目的】探讨低温弱光胁迫下不同基因型棉花幼苗叶绿素荧光特性及能量分配的响应机制,为棉花耐低温品种选育及筛选耐低温鉴定指标和方法提供理论依据。【方法】以6种不同基因型棉花幼苗为试材,通过5℃、100μmol/(m2.s)低温弱光处理,测定12 h内叶绿素荧光相关参数。【结果】低温弱光胁迫提高了初始荧光Fo、光合功能相对限制值L(PFD),显著降低了PSII最大光化学效率Fv/Fm、PSII实际光化学效率ΦPSII、光合电子传递速率ETR、光化学猝灭系数qP等指标,非光化学猝灭系数NPQ则呈现先升后降的趋势;同时,PSI激发能分配系数σ、天线热耗散速率Drate增大,PSII激发能分配系数β、光化学速率Prate降低。【结论】低温弱光胁迫导致棉花幼苗叶片PSII光化学活性降低,光合电子传递过程受抑,更多的光能用于天线热耗散,且干扰了PSI和PSII间的激发能分配和传递。综合各指标分析,新陆中28号与中棉所50号在低温弱光胁迫下表现出良好的光能分配、利用能力,耐低温能力较强,新陆早42号与中棉所43号次之,新陆早33号和新陆早19号较差。【Objective】The aim of this study was to investigate the response mechanism of chlorophyll fluorescence characteristics and energy allocation in leaves of cotton seedlings under low temperature and weak light stress,and to provide a theoretical basis to screen suitable indexes for evaluating chilling-tolerance of cotton varieties.【Method】Chlorophyll fluorescence parameters in leaves of cotton seedlings of six different genotypes were determined under 5℃、100 μmol/（m2·s） in 12 hours.【Result】Under low temperature and weak light stress,the initial fluorescence（Fo） and the PFD limitation（L（PFD）） increased significantly,whereas the maximal efficiency of PSII photochemistry（Fv/Fm）,photochemical efficiency of open reaction centers of PSII（Fv′/Fm′）,quantum yield of PSII electron transport（ΦPSII）,electron transport rate（ETR）,photochemical quenching（qP） decreased dramatically,and the level of non-photochemical quenching（NPQ） increased at the initial stage and decreased at the later stage.At the same time,PSI distribution index of excitation energy（σ） and antenna heat dissipation rate（Drate） increased significantly,PSII distribution index of excitation energy（β） and Photochemical effieiency（Prate） decreased.【Conclusion】The results indicate that low temperature and weak light stress decreased the activity of PSII reaction center and photochemical electron transfer rate,inhibited pathways of photosynthetic electron transport,and distribution balance of excitation energy between PSI and PSII,which led to the structural damage of photosynthetic apparatus and functional descend in photosynthetic ability.Analysis of these chlorophyll fluorescence parameters of the leaves of all the cotton genotypes showed that these varieties performed cold tolerance in the order： Xinluzhong28 and Zhongmiansuo50Xinluzao42 and Zhongmiansuo43Xinluzao33 and Xinluzao19.

关 键 词：棉花 幼苗 基因型 低温弱光胁迫 叶绿素荧光 能量分配 

分 类 号：S562[农业科学—作物学]