摘要
观测了离体小麦叶片衰老进程中685nm光诱导荧光动力学的变化,发现曲线的第二峰首先消失,F_v(F_p-F_t)、F_p-F_t和F_v/F_o比值迅速下降,达最大荧光P点的时间缩短。推测衰老叶片中PQ分子数目的减少是光合能力丧失的主要原因。用6-BA处理叶片,阻止了F_v和F_v/F_o比值的下降,与对照相比,衰老第三天仍保持第二峰;此外,核黄素使第二峰消失,而核黄素+BA与BA效果相似;同时叶片衰老时SOD活性的下降和膜脂过氧化作用均被延缓,据此探讨了BA作为自由基清除剂延缓叶片衰老的可能机理。
The kinetics of 685 nm chlorophyll fluorescence emission from wheat (Triticum aestivum L.) leaves were measured during senescence. It were found that the second peak (S to M rise) in induction curves disappered firstly, variable fluorescence (Fv:Fp-Fo), Fp-Ft and the ratio of Fv/Fo were decreased rapidly, and the time taken to reach P posnt of the curve reduced. All these indicated that fewer plastoquinone (PQ) molecules in old leaves were responsible for this decline in photosynthetic capability. Treatments of detached wheat and maize (Zea mays L.) leaves with 6-BA, not only could strongly inhibit the decrease of the ratio of Fv/Fo and Fv, but also sustain the second peak. In addition, the second peak disappered when the leaves were treated with riboflavin after 3 days in darkness, but BA + riboflavin kept it. Meanwhile the decrease of superoxide dismutase activity and the increase of lipid peroxidation was also delayed. Thus, the possible mechanism of BA in preventing senescence as the scavenger of free radicals was discussed.
出处
《北京大学学报（自然科学版）》
CAS
CSCD
北大核心
1991年第6期700-706,共7页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
国家自然科学基金
关键词
叶片
衰老
叶绿素
荧光动力学
F685nm kinetics
Photosynthetic electron transport
6-Benzyladenine (BA)
Scavenger of free radicals
Leaf senescence
