论文部分内容阅读
【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 objective of this study was to investigate the response mechanism of chlorophyll fluorescence characteristics and energy allocation to different genotypes of cotton seedlings under low temperature and poor light stress and to provide a theoretical basis for the selection of cotton low temperature tolerant cultivars and selection of identification indexes and methods of low temperature tolerance. 【Method】 Six different genotypes of cotton seedlings were used as test materials, and the chlorophyll fluorescence parameters were measured within 12 h by low temperature and low light intensity of 100μmol / (m2.s) at 5 ℃. 【Result】 Under low temperature and low light stress, the initial fluorescence Fo and the relative limiting value L (PFD) of photosynthetic function were increased, and the maximum photochemical efficiency of PSII Fv / Fm, the actual PSII photochemical efficiency ΦPSII, the photosynthetic electron transfer rate ETR, photochemical quenching coefficient qP, the non-photochemical quenching coefficient NPQ firstly increased and then decreased. At the same time, PSI excitation energy distribution coefficient σ, antenna thermal dissipation rate Drate increased, PSII excitation energy distribution coefficient β and photochemical rate Prate decreased. 【Conclusion】 Low temperature and poor light stress led to the decrease of photochemical activity of PSII in cotton seedling leaves and the inhibition of photosynthetic electron transport. More light energy was used to dissipate the heat of the antenna and interfere with the distribution and transfer of excitation energy between PSI and PSII. According to the analysis of various indicators, Xinluzhong 28 and Zhongmianhuo 50 showed good light distribution, utilization ability and low temperature tolerance under low temperature and low light stress. Xinluzao 42 and Zhongmian 43 Second, the new land as early as 33 and the new land as early as 19 worse.