白条纹水稻突变体的光合特性分析

Photosynthetic Characterization of White Stripe Mutant ws in Rice Oryza sativa

从水稻组织培养突变体中发现可稳定遗传的白色条纹突变体,其生育期呈现白色和绿色条带相间的表型。电镜观察表明突变体绿色条带叶肉细胞具有正常的叶绿体发育,白色条带叶肉细胞则表现出叶绿体缺失。与野生型相比,突变体单位重量叶片叶绿素含量显著下降,但叶绿素光能吸收强度略有上升。突变体类囊体膜上的光系统II产生的激发能量降低,并将更多的激发能分配给光系统I。突变体保持叶片光合效率稳定的机制是通过提高胡萝卜素与叶绿素比值来补偿光合色素含量和激发能的降低引起的光合效率下降。

A white stripe mutant was found from rice tissue culture mutant library.Its whole growth period showed white and green stripe phenotypes and expressed genetic stability.Electron microscopy observation showed that mesophyll cells of green belt with normal chloroplast development,whilst mesophyll cells of white belt with chloroplast absence.Compared with the wild type,mutant chlorophyll content per unit weight decreased significantly,but light absorption intensity of per unit chlorophyll increased slightly.The excitation energy of photosystem II in thylakoid membrane in the mutant reduced significantly,and more excitation energy was distributed to photosystem I comparing to wild type.The increase of carotene and chlorophyll ratio to cope with the decrease of pigment content,and excitation energy was the main mechanism to keep photosynthetic efficiency stable in mutant.