POLYPHASIC CHLOROPHYLL a FLUORESCENCE TRANSIENT IN PLANTS AND CYANOBACTERIA *
POLYPHASIC CHLOROPHYLL a FLUORESCENCE TRANSIENT IN PLANTS AND CYANOBACTERIA *
复制标题
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
Reto J Strassert;Alaka Srivastava 'and Govindjee
中科院分区：
文献类型：
--
作者：
Reto J Strassert;Alaka Srivastava 'and Govindjee
已知可变的叶绿素（Chl）a荧光产率与放氧生物的光系统I1（PSII）的光化学活性有关。荧光从最低产量F1上升到最高产量F1的动力学是所有PSII中心中净还原的初级结合质体醌（QA）随时间的积累的监测器。使用无快门系统（植物效率分析仪，Hansatech，英国），它允许数据积累超过几个数量级的时间（40 11秒至120秒），我们已经测量了对数时间尺度上，第一次，完整的多相荧光上升的各种产氧植物和蓝藻在不同的光强度。随着光强的增加，荧光从典型的0-I-P特性曲线变为具有两个中间水平J和I的曲线，这两个水平在高光强下均显示饱和，但强度依赖性不同。在生理条件下，所有生物体的Chl a荧光瞬变都遵循0-J-I-P的顺序。相对于光强和温度的动力学特征表明，0-J相是光化学相，导致QA还原为QA-。建议中间水平I与质体醌池填充的异质性有关。当所有质体醌（PQ）分子被还原为PQH 2时，达到P。加入3-（3-4-氯苯基）1，1-二甲基脲导致O-J-I-P上升转变为O-J上升。发现此处观察到的0-J-I-P的动力学与Neubauer和Schreiber报道的0-1，-12-P的动力学相似（2.自然的。42c，1246-1254，1987）。讨论了荧光步骤0-J-I-P与PSII反应填充质体醌池的生化意义。
The variable chlorophyll (Chl) a fluorescence yield is known to be related to the photochemical activity of photosystem I1 (PSII) of oxygen-evolving organisms. The kinetics of the fluorescence rise from the minimum yield, F,, to the maximum yield, F,, is a monitor of the accumulation of net reduced primary bound plastoquinone (QA) with time in all the PSII centers. Using a shutter-less system (Plant Efficiency Analyzer, Hansatech, UK), which allows data accumulation over several orders of magnitude of time (40 11s to 120 s), we have measured on a logarithmic time scale, for the first time, the complete polyphasic fluorescence rise for a variety of oxygenic plants and cyanobacteria at different light intensities. With increasing light intensity, the fluorescence rise is changed from a typical 0-I-P characteristic to curves with two intermediate levels J and I, both of which show saturation at high light intensity but different intensity dependence. Under physiological conditions, Chl a fluorescence transients of all the organisms examined follow the sequence of 0-J-I-P. The characteristics of the kinetics with respect to light intensity and temperature suggest that the 0-J phase is the photochemical phase, leading to the reduction of QA to QA-. The intermediate level I is suggested to be related to a heterogeneity in the filling up of the plastoquinone pool. The P is reached when all the plastoquinone (PQ) molecules are reduced to PQH2. The addition of 3-(3-4-dichIorophenyl)1,l -dimethylurea leads to a transformation of the 0-J-I-P rise into an 0-J rise. The kinetics of 0-J-I-P observed here was found to be similar to that of 0-1,-12-P, reported by Neubauer and Schreiber (2. Naturforsch. 42c, 1246-1254, 1987). The biochemical significance of the fluorescence steps 0-J-I-P with respect to the filling up of the plastoquinone pool by PSII reactions is discussed.