Biology Department, Nuclear Research Center "Demokritos", Athens, Greece.
Photosynth Res. 1986 Jan;10(3):171-80. doi: 10.1007/BF00118280.
The development and organization of the Photosynthetic units follow a step-wise assembly process. First the core complexes of the PSI and PSII units are formed, followed by their light-harvesting components; then an assembly process of these components into supramolecular structures takes place. Parallel to this, the control of excitation energy distribution between the two photosystems is established. This control is attributed to the modulation of the PSI unit effective cross section, which is possible only when LHC-I is formed and assembled into CPIa. Parallel to the formation of PSI and PSII, the electron carriers are synthesized and the electron transport chain is assembled. The number of PSII units operating per electron transport chain remains constant throughout development and equal to that of the mature chloroplast, but the number of PSI units per chain varies with PSII unit size. During development, when the rate of Chla synthesis is low, relative to the other thylakoid components, or is completely stopped, then the newly formed or preexisting LHC-I and LHC-II proteins are digested and their Chla is used for the formation of PS core complexes.
光合单位的发育和组织遵循逐步组装的过程。首先形成 PSI 和 PSII 单位的核心复合物，然后是它们的光捕获组件；然后这些组件组装成超分子结构。与此同时，两个光系统之间的激发能分布的控制也建立起来。这种控制归因于 PSI 单位有效横截面积的调制，只有当 LHC-I 形成并组装成 CPIa 时才有可能。与 PSI 和 PSII 的形成平行，电子载体被合成，电子传递链被组装。每个电子传递链上运行的 PSII 单位数量在整个发育过程中保持不变，与成熟叶绿体中的数量相等，但每个 PSI 单位的数量随 PSII 单位大小而变化。在发育过程中，当 Chla 合成的速度相对于其他类囊体成分较低或完全停止时，新形成的或预先存在的 LHC-I 和 LHC-II 蛋白被消化，它们的 Chla 用于 PS 核心复合物的形成。
