低温弱光下辣椒叶片PSII光能吸收和转换变化及与品种耐性的关系

Correlations Between Changes of Absorption and Transformation of Light Energy by PSII in Pepper Leaves and the Variety Tolerance Under Low Temperature and Weak Light

【目的】研究低温弱光下辣椒叶片PSII光能吸收和转换规律,分析其与品种耐低温弱光性的相关性,筛选和建立快速、准确、无损伤的辣椒耐低温弱光性鉴定指标和方法。【方法】以耐低温弱光性不同的12个辣椒品种为试材,以冷害指数作为品种耐性鉴定的依据,应用调制荧光测定技术,采用相关分析的方法,研究低温弱光下辣椒叶片PSII光能吸收和转换规律及其与品种耐低温弱光性的关系。【结果】15℃/5℃、100μmol.m-2.s-1低温弱光处理使辣椒叶片PSⅡ的实际光能转化效率ΦPSⅡ、开放的PSⅡ有效光能转化效率Fv′/Fm′、光化学猝灭系数qP、光下最大荧光Fm′、光下最小荧光Fo′和光下最大可变荧光Fv′均降低,非光化学猝灭系数NPQ和稳态荧光Fs增大,最大光能转化效率Fv/Fm变化不显著。15℃/5℃、100μmol.m-2.s-1低温弱光处理15 d辣椒叶片的ΦPSⅡ和Fv′与辣椒的冷害指数呈极显著负相关,Fv′/Fm′、qP和Fm′呈显著负相关,NPQ呈显著正相关。【结论】15℃/5℃、100μmol.m-2.s-1低温弱光处理15 d辣椒叶片的ΦPSⅡ、Fv′/Fm′、qP、NPQ、Fm′和Fv′等叶绿素荧光参数可用于辣椒耐低温弱光性快速、准确、无损伤的鉴定指标,其中ΦPSⅡ和Fv′为最敏感的指标。

【Objective】 The objective of this study is to explore the correlations between the changes of absorption and transformation of light energy by PSII in pepper leaves and the variety tolerance under low temperature and weak light,and to screen suitable indexes for evaluating chilling-and weak light-tolerance of pepper varieties.【Method】 The correlations between the changes of chlorophyll fluorescence parameters and the tolerance of 12 pepper varieties expressed as injury indexes under low temperature and weak light were studied by using modulated chlorophyll fluorescence techniques and correlation analysis.【Result】 After treated with low temperature（15℃/5℃,day/night） and weak light（100 μmol？m-2？s-1）,the ΦPSⅡ（actual photochemical efficiency of PSⅡ）,Fv′/Fm′（photochemical efficiency of open reaction centers of PSⅡ）,qP（photochemical quenching）,Fm′（maximal fluorescence in light-adapted state）,Fo′（minimal fluorescence in light-adapted state） and Fv′（variable fluorescence in light-adapted state） in leaves of 12 pepper varieties decreased,NPQ（non-photochemical quenching） and Fs（steady-state fluorescence） increased,wherease the Fv/Fm changed little in leaves of 12 pepper varieties.Significant negative correlations between chilling injury indexes and ΦPSⅡ,Fv′/Fm′,qP,Fm′ or Fv′ were observed in 12 pepper variety leaves treated with low temperature and weak light for 15 days;wherease a significant positive correlation between chilling injury indexes and NPQ was observed in pepper leaves treated with low temperature and weak light conditions for 15 days.【Conclusion】 It was proposed that ΦPSⅡ,Fv′/Fm′,qP,NPQ,Fm′ and Fv′ in leaves of pepper treated with 15°C/5°C,100 μmol？m-2？s-1PFD for 15 days could be used as simple and convenient tools for identification and screening a large number of chilling and weak-light tolerant pepper varieties.Among these parameters,ΦPSⅡ and Fv′ were the most sensitive ones.