FLUORESCENCE AND OXYGEN EVOLUTION FROM CHLORELLA PYRENOIDOSA
FLUORESCENCE AND OXYGEN EVOLUTION FROM CHLORELLA PYRENOIDOSA
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DOI：
10.1016/0005-2728(69)90168-6
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发表时间：
1969-01-01
期刊：
影响因子：
--
通讯作者：
MYERS, J
中科院分区：
文献类型：
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作者：
BONAVENTURA, C;MYERS, J
通过同时测量瞬态和稳态释氧速率和荧光速率，研究了蛋白核小球藻光合能量转换过程。 1.1．光 1 和光 2 照明的交替或叠加会引起荧光和 O2 释放速率的快速和缓慢变化。快速变化归因于 Hill-Bendall1 模型以及 Eley 和 Myers2 动力学分析中反应中心条件的变化。缓慢的变化被解释为对照明强度和波长的适应。自适应机制是根据传递到系统 2 的总吸收量子分数 (α) 的缓慢变化来描述的。在低强度下，适应光 2 照明（光 2 状态）的细胞的 α 计算值约为 1。对于适应光1照明（光1状态）的细胞，α为0.9。2.2。发现在光 1 或光 2 激发的光饱和开始时，荧光产量增加伴随着 O2 产量的减少。建议使用 α 的变化来解释稳态条件下观察到的最大荧光产量与瞬态条件下或 3(3,4-二氯苯基)-1,1-二甲基脲抑制的细胞中观察到的 1.5 倍高最大荧光产量之间的差异。 α 的变化也可以解释在给定的 O2 演化稳态速率下观察到光 1 激发的荧光发射率高于光 2 激发的荧光发射率。3.3。系统 2 的能量转换模型被提出来解释我们的观察结果。该模型提出通过反应中心的光化学捕获以及系统 2 的颜料床和反应中心的荧光和无辐射去激发来竞争性耗散吸收的能量。
The process of photosynthetic energy conversion inChlorella pyrenoidosawas investigated by simultaneous measurement of transient and steady-state rates of O2evolution and fluorescence.1.1. Alternation or superimposition of light 1 and light 2 illumination induces both fast and slow changes in fluorescence and rate of O2evolution. The fast changes are ascribed to changes in conditions of the reaction centers in the context of theHill-Bendall1model and the kinetic analysis ofEley and Myers2. The slow changes are interpreted as adaptations to the intensity and wavelength of illumination. The adaptive mechanism is described in terms of slow variation in fraction (α) of total absorbed quanta delivered to System 2. At low intensities, the calculated value of α for cells adapted to light 2 illumination (light 2 state) is approx. 0.9 of α for cells adapted to light 1 illumination (light 1 state).2.2. An increase in fluorescence yield was found to accompany the decrease in O2yield at the onset of light saturation with either light 1 or light 2 excitation. Variation in α is proposed to account for the differences between the maximum fluorescence yield observed in steady-state conditions and the 1.5 times higher maximum yield observed in transient conditions or in cells inhibited by 3(3,4-dichlorophenyl)-1,1-dimethylurea. Variation in α can also explain the observation of a higher rate of fluorescence emission with light 1 excitation than with light 2 excitation for a given steady-state rate of O2evolution.3.3. A model for energy conversion by System 2 is proposed to account for our observations. The model proposes competitive dissipation of absorbed energy by photochemical trapping at reaction centers and by fluorescence and radiationless de-excitation from both the pigment bed and reaction centers of System 2.