摘要
Cd^(2+)使叶绿体低温(77K)荧光发射光谱中 F686/F736及 F696/F736和激发光谱中F480/F436比值降低,说明 Cd^(2+)不利于激发能向 PSⅡ传递。SDS-PAGE 分析表明,Cd(2+)处理后叶绿体类囊体膜中光系统Ⅱ捕光叶绿素蛋白质复合物 LHCⅡ的部分寡聚体解聚成单体,且 LHCⅡ的总量也减少了。分析表明 Cd^(2+)使属于 LHCⅡ的多肽减少。已知LHCⅡ在光能吸收、传递以及激发能在两个光系统间的分配和调节方面起着重要作用,Cd^(2+)引起部分 LHCⅡ解聚和总量减少,必然导致由 LHCⅡ捕获和向光系统Ⅱ中心传递的能量减少。
The fluorescence emission and excitation spectra at 77 K showed that Cd^(2+) treatment re- duced the ratio of F686/F736,F696/F736 and F480/F436 in spinach chloroplasts.It is suggested that Cd^(2+) impeded the excitation energy transfer from light harvesting chlorophyll to PSⅡ trap. The chlorophyll protein complexes of spinach chloroplasts were resolved by SDS-PAGE.It showed that the total amount of LHCⅡ decreased after Cd^(2+) treatment.A decrease of 27 kD polypeptide in LHCII was also found by the treatment of Cd^(2+).Since LHCⅡ play an im- portant role in the absorption and transfer of light energy and the distribution of excitation energy between PSⅡ and PSⅠ,a decrease of LHCⅡ certainly may cause a decrease of excita- tion energy transfer from LHCⅡ to PSⅡ reaction center.
基金
国家自然科学基金
关键词
镉离子
类囊体膜
色素蛋白质
菠菜
Cadmium ions
Thylakoid membranesvChlorophyll protein complexes
