Endoplasmic reticulum and microtubule formation in dividing cells of higher plants-a postulate.

In spite of the increase in volume of literature on the fine structure of events during division in cells of higher plants, the presence of any kind of a centriole or centriole-like structure has not been demonstrated. However, recent studies have contained data which point to a relationship between membranous elements (usually smooth endoplasmic reticulum) and spindle microtubules in polar regions of dividing cells. These previously reported data, together with data in this present work, are combined into the formulation of an hypothesis relative to the possible role of membranes, particularly smooth endoplasmic reticulum, as cell centers in the assembly and disposition of spindle microtubules in dividing cells of higher plants.