open access

https://hdl.handle.net/2115/53357

Ultrastructural study of plasmodesmata in the brown alga Dictyota dichotoma (Dictyotales, Phaeophyceae)

英語

Plasmodesmata

2012-10

Springer-Verlag

Planta

236(4)

1013-1026

Plasmodesmata (PD) singular: plasmodesma, from the Greek plasma=cytoplasm and desmos=connection) are intercellular bridges of multicellular plants, directly connecting cytoplasms of neighboring cells. They play a crucial role in cell-to-cell communication and cell development. Although brown algae (Phaeophyceae, Heterokontophyta) are phylogenetically far from the lineage of land plants, they possess a complex multicellularity with PD like green plants. In this study, the ultrastructure and the formation of PD in the brown alga Dictyota dichotoma, were studied using transmission electron microscopy (TEM) and electron tomography with rapid freezing and freeze-substitution. D. dichotoma, possesses plasma membrane-lined simple PD without an internal endoplasmic reticulum (ER) (desmotubule), different from those of land plants. PD were clustered in thin cell wall regions forming pit fields. Fine proteinaceous internal bridges were observed in the cavity. Ultrastructural observations of cytokinesis of D. dichotoma revealed that the PD formation started from an early stage of cytokinesis with the formation of tubular pre-plasmodesmata (PPD) within the membranous sacs (MSs) of the cytokinetic diaphragm. Clustering of these PPD became into the future pit field. As cytokinesis proceeds, electron-dense material extended from the outer surface of the middle part of PPD and finally formed the nascent cell wall. From these results, it is suggested that PPD would be associated with the cell wall development during cytokinesis of D. dichotroma.

学術雑誌論文

Accepted Manuscript

The original publication is available at www.springerlink.com

0032-0935