摘要
增强的紫外线-B(ultraviolet-B,UV-B)辐射对植物生长具有抑制效应的观点已被广泛接受,而低剂量的UV-B辐射是否也可像其它弱胁迫一样促进植物的光合作用,目前还不清楚。本研究运用荧光光谱技术,针对在低剂量UV-B辐射环境中生长的植物,分析其光系统Ⅱ(photosystemⅡ,PSⅡ)中能量吸收及传递的过程。稳态荧光激发及发射光谱显示,增强的低剂量UV-B辐射使荧光发射强度增加,并改变了各个高斯光谱组分的比例。7天的UV-B辐射,使捕光色素蛋白复合物(light-harvesting complexⅡ,LHCⅡ)吸收的大部分能量传递到反应中心(reaction center,RC),是对照组的近两倍。对照组和UV-B处理组的超快荧光动力学曲线拟合结果都得到3组时间组分:小于100 ps,几百ps及几个ns。荧光谱高斯解析及荧光动力学曲线时间拟合结果表明,低剂量的UV-B辐射加快了PSⅡ中LHCⅡ向RC的能量传递,并使传递到RC的能量增加,这将有助于植物的生长。说明低剂量UV-B辐射作为一种弱胁迫,提高了植物利用能量的效率。该结果有助于全面了解UV-B辐射对植物生长,尤其是对其光合作用过程的影响及其机制。
Inhibited effect of ultraviolet-B（UV-B） on plant growth has been accepted widely,while whether low dose UV-B radiation could be a stimulator accelerating photosynthesis of plant just like other stress is still unknown.The influence of low-level UV-B radiation on primary energy transfer progress of photosystem Ⅱ（PS Ⅱ） was studied with fluorescence spectrum technology.The increase of fluorescence intensity in UV-B experiment group was observed by steady-state fluorescence excitation and emission spectra.We found that the proportion of Gauss deconvolution spectrum component of emission spectra were altered by UV-B irradiation,and the most part of energy absorbed by LHCII was transferred to RC under 7-d UV-B radiation,which was the twice as the control.Moreover,ultrafast fluorescence decay curve of control and UV-B groups were analyzed by three groups of time component：less than 100 picoseconds,several hundreds picoseconds and several nanoseconds.The results of Gauss deconvolution component and fluorescence dynamic curve indicate that low dose UV-B radiation speed up energy transfer from light-harvest antenna to reaction center of PSII,and increase energy distribution to reaction center at the same time.It will be benefit for promotion of plant growth.All these results illustrate that low-level UV-B radiation could be a kind of low-level stress to raise energy utilization efficiency of PSII.These results can help us to fully understand the effect of UV-B radiation on plant growth,especially the influence of photosynthesis process and its mechanism.
出处
《生物物理学报》
CAS
CSCD
北大核心
2011年第10期839-848,共10页
Acta Biophysica Sinica
基金
国家自然科学基金项目(30670366
31070362)
陕西省自然科学基金项目(2009JQ3004)
陕西省教育厅基金项目(2010JK856)~~
关键词
低剂量紫外线-B
光系统Ⅱ
荧光
能量传递
Low dose ultraviolet-B
Photosystem Ⅱ
Fluorescence
Energy transfer
