Abstract
The progression of leaf senescence is generally defined by chlorophyll degradation and decline of photosynthetic ability. As some morphological change in chloroplast before degradation is recognized, and many senescence–associated genes are reported, the study on chloroplast along the leaf development and senescence would be useful to understand the role of leaves in this period. We monitored the chloroplasts morphologically by microscopic method of Arabidopsis thaliana. Just after the leaves fully expanded, the chloroplast having waved lamella structure appeared among the typical chloroplasts. Every chloroplast in each leaf looked completed such morphological change when the plant had seeds. The ultra-structure of chloroplast with disorientation of the thylakoid membrane and the curling grana structure was observed by electron microscopy. These chloroplasts looked increasing one by one among the cells, but not appearing simultaneously in a cell. The values of chlorophyll a/b ratio were almost the same through the experiment period.
