摘要
通过叶绿素荧光技术研究了二硫苏糖醇 ( 1 ,4 dithiothreitol,DTT)对大豆叶片光系统I(PSI)和光系统Ⅱ (PSⅡ )间激发能分配的影响。结果显示 :DTT处理没有影响叶片最大光化学效率 (Fv/Fm) ,但光下叶绿素荧光降低比率 (Rfd)下降 ;强光下 ,DTT处理叶片PSⅡ开放反应中心激发能捕获效率 (Fv′/Fm′)比对照高 3 0 %～ 40 % ;分配给PSⅠ的激发能比对照叶片低约 3 0 % ,分配给PSⅡ的激发能比对照叶片高 2 0 %左右 ,激发能分配严重偏离平衡状态 ;DTT处理叶片PSⅡ的激发能压力 ( 1 -qP)较对照高 ,但非光化学猝灭(qN)明显比对照低 ;进一步的实验揭示DTT的引入抑制了玉米黄质 (Z)的生成和状态转换 (qT)。据此 ,推测DTT可能通过抑制天线色素的调节能力导致两光系统间激发能分配失衡。
Chlorophyll fluorescence technique was used to investigate the effect of 1,4-dithiothreitol(DTT) on the distribution of excited energy between photosystem I(PS I) and photosystem II (PS II) in soybean leaves under high irradiance. The maximum PS II quantum yield(F v/F m) was hardly affected by the presence of DTT (Table 1,Fig.1), however, the chlorophyll fluorescence decrease ratio (R fd ) depressed drastically under 1 400 μmol m -2 s -1 irradiance(Fig.2). Efficiency of excitation captured by open PS II centers (F v′/F m′) was enhanced about 30%-40% by DTT treatment(Fig.3a), whereas photochemical quenching (q P) was depressed by about 40% (Fig.3b) by high irradiance. DTT treatment caused a 30% decrease in allocation of excited energy to PS I under strong light(Fig.4a) and a 20% increase to PS II(Fig.4b). Serious imbalance of excited energy distribution was observed in DTT-treated leaves(Fig.5). Though high excitation pressure(1-q P) resulted from DTT treatment(Fig.6a) , non-photochemical quenching(q N) was lowered(Fig.6b). Other experiments revealed that DTT completely inhibited the formation of zeaxanthin (Z)(Table 2), and also depressed the state transition(q T) significantly(Fig.7). It is suggested that the imbalance of excitation distribution between the two photosystems induced by DTT was mainly due to the enhancement of excitation energy capture by PS II antenna, and the imbalance induced the depression of R fd and activity of photosynthesis.
出处
《植物生理与分子生物学学报》
CAS
CSCD
2003年第6期561-568,共8页
Journal Of Plant Physiology and Molecular Biology
基金
国家重点基础研究发展规划项目 (G19980 10 10 0 )资助
关键词
叶绿素荧光
二硫苏糖醇
激发能分配
叶黄素循环
状态转换
chlorophyll fluorescence
1,4-dithiothreitol
excited energy distribution
xanthophyll cycle
state transition
