Department of Plant and Soil Biology, Hilgard Hall, University of California, Berkeley, California 94720.
Plant Physiol. 1985 Nov;79(3):872-8. doi: 10.1104/pp.79.3.872.
The composition and structural organization of thylakoid membranes of a low chlorophyll mutant of Beta vulgaris was investigated using spectroscopic, kinetic and electrophoretic techniques. The data obtained were compared with those of a standard F1 hybrid of the same species. The mutant was depleted in chlorophyll b relative to the hybrid and it had a higher photosystem II/photosystem I reaction center (Q/P(700)) ratio and a smaller functional chlorophyll antenna size. Analysis of thylakoid membranes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the mutant lacked a portion of the chlorophyll a/b light-harvesting complex but was enriched in the photosystem II reaction center chlorophyll protein complex. Comparison of functional antenna sizes and of photosystem stoichiometries determined electrophoretically were in good agreement with those determined spectroscopically. Both approaches indicated that about 30% of the total chlorophyll was associated with photosystem I and about 70% with photosystem II. A greater proportion of photosystem II(beta) was detected in the mutant. The results suggest that a higher photosystem II to photosystem I ratio in the sugar beet mutant has apparently compensated for the smaller photosystem II chlorophyll light-harvesting antenna in its chloroplasts. Moreover, a lack of chlorophyll a/b light-harvesting complex correlates with the abundance of photosystem II(beta). It is proposed that a developmental relationship exists between the two types of photosystem II where photosystem II(beta) is a precursor form of photosystem II(alpha) occurring prior to the addition of the chlorophyll a/b light-harvesting complex and grana formation.
用光谱学、动力学和电泳技术研究了菠菜低叶绿素突变体的类囊体膜的组成和结构组织。将获得的数据与同一物种的标准 F1 杂种进行了比较。与杂种相比，突变体中叶绿素 b 含量减少，并且具有更高的光系统 II/光系统 I 反应中心（Q/P(700)）比和更小的功能叶绿素天线大小。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析类囊体膜表明，突变体缺乏一部分叶绿素 a/b 光捕获复合物，但富含光系统 II 反应中心叶绿素蛋白复合物。电泳确定的功能天线大小和光系统化学计量学的比较与光谱学确定的结果非常吻合。这两种方法都表明，大约 30%的总叶绿素与光系统 I 相关，约 70%与光系统 II 相关。在突变体中检测到更多的光系统 II(beta)。结果表明，在糖甜菜突变体中，较高的光系统 II 与光系统 I 比值显然弥补了其叶绿体中较小的光系统 II 叶绿素光捕获天线。此外，缺乏叶绿素 a/b 光捕获复合物与光系统 II(beta)的丰度相关。提出了两种类型的光系统 II 之间存在发育关系，其中光系统 II(beta)是在添加叶绿素 a/b 光捕获复合物和形成粒状结构之前出现的光系统 II(alpha)的前体形式。
