摘要
黄瓜幼苗的冷锻炼与低温引起的光抑制李晓萍，陈贻竹，李平，郭俊彦（中国科学院华南植物研究所，广州５１０６５０）关键词：低温引起的光抑制，荧光猝灭，冷锻炼，黄瓜幼苗低温使植物利用光能的能力降低从而引起或加剧光抑制（ｈａｓ等１９８３）。在光抑制中常以叶绿素...
By chlorophyll fluorescence quenching analysis, we studied the susceptibility of cucumber (Cucumis sativus L. ) seedlings to excessive light induced by low temperatue. At 2℃ and 250αmol photons m-2 s-1 the decrease of Fv/Fm in chilling-acclimated seedlings was greater than that in acclimated seedlings, but Fv/Fm recovered more quickly in chilling-acclimated seedlings (Fig. 1 ). This indicates that the decrease of Fv/Fm is not solely the result of damage of the PSII caused by photoinhibition under chilling but is due to the protective response of the photosynthetic apparatus to the stress. At 4℃,a temperature causing chilling damage in cucumber seedlings, both the photochemical quenching (qP ) and the nonphotochemical one (qN) of chlorophyll fluorescence were suppressd. At 12℃,qP was suppressed but qN was not.When the seedlings were acclimated at 12℃ for 2 days and then transferred to 4℃, their qN increased more than 20% under light intensities ranging from 20 to 400 μmol photons m-2 s-1as compered with those of unacclimated seedlings (Figs. 2a, b, c and Table. 1). The results indicate that chilling acclimation enhances the ability of light energy dissipation by nonphotochemical processes under chilling and illumination. This maybe the reason of the greater decrease in Fv/Fm in chilling-acclimated seedlings when photoinhibited in light and at chilling temperature and also one of the causes of increased tolerance induced by chilling acclimation to excessive light.
基金
国家自然科学基金
关键词
黄瓜
幼苗
冷锻炼
低温
光抑制
photoinhibition induced by low temperature, chlorophyll fluorescence quenching, chilling acclimation, cucumber seedling
