Abstract
The preprophase band (PPB) of plants is a ring-like band of microtubules that underlies the plasma membrane in prophase. Although the PPB disappears in prometaphase, the newly formed cell plate attaches to the former PPB site at cytokinesis. The PPB plays an important role in determination of division site in a plant cell. Clathrin-coated vesicles (CCV) as well as structurally related non-coated vesicles (NCV) were frequently observed at the PPB. To understand the role of the vesicles in the PPB development, we quantitatively analyzed effects of cytochalasin D on the distribution and the morphology of these vesicles in high-pressure frozen onion epidermal cells by electron tomography. Our data suggest that the NCVs fuse each other and actin cytoskeleton is involved in formation of the CCVs and the fusion of the NCVs. These result support the idea that the NCVs are involved in the endocytic pathway.
