Ried A, Hessenberg B, Metzler H, Ziegler R
Biochim Biophys Acta. 1977 Feb 7;459(2):175-86. doi: 10.1016/0005-2728(77)90020-2.
Action spectra of light reaction I and light reaction II from red algae (marine members of Florideae and Bangiales) were measured with 550 nm (light 2) or 699 nm light 1) background light, using a Teflon-covered platinum electrode for O2 measurement. Care was taken to ensure that maximum enhancement was reached by the background light. The action spectra of light reaction I, we found under these conditions, are very similar to the thallus absorption, whilst the action spectra of light reaction II show, besides strong bands of the phycobilins, only minor bands of chlorophyll a, which account for only 10-20% of the total chlorophyll. The spectra are discussed on the basis of two main types of models of energy distribution over both photosynthetic systems. If this distrubution is considered to be invariable (models 1a and b), one has to assume that almost exactly half of the total chlorphyll is not involved in the supply of the non-cyclic electron transport with excitation energy. This part, however, has to be thought of as incorporated in the thylakoid membrane in a similar manner to the chlorophyll in photosystem I. However, if one supposes an almost complete equilibration in the energy distribution over both systems as long as the primary absorption in photosystem II prevails (models 2a and b), there is no need for the assumption of such photosynthetically 'inactive' or less active chlorophyll. Some evidence is shown that strongly supports model 2.
使用覆盖有特氟龙的铂电极测量氧气，在550纳米（光2）或699纳米（光1）背景光下，测定了红藻（海生的海索面科和红毛菜科成员）光反应I和光反应II的作用光谱。注意确保背景光达到最大增强效果。我们发现在这些条件下，光反应I的作用光谱与藻体吸收非常相似，而光反应II的作用光谱除了藻胆蛋白的强吸收带外，仅显示叶绿素a的微弱吸收带，其仅占总叶绿素的10 - 20%。基于能量在两个光合系统上分布的两种主要模型类型对光谱进行了讨论。如果认为这种分布是不变的（模型1a和b），则必须假设几乎正好一半的总叶绿素不参与为非循环电子传递提供激发能。然而，这部分叶绿素必须被认为是以与光系统I中的叶绿素类似的方式并入类囊体膜中的。但是，如果假设只要光系统II中的初级吸收占主导，两个系统之间的能量分布就几乎完全平衡（模型2a和b），那么就无需假设存在这种光合“无活性”或活性较低的叶绿素。有一些证据有力地支持了模型2。
