have from four-seven cisternae, and their peripheral regions liberate small and not very dense vesicles, that become dispersed in the cytoplasmic matrix (Fig.
In addition to lacking mitochondria, dictyosomes
, and non-microtubular cytoskeletal structures, this species has some ultrastructural peculiarities including paired nuclei and basal bodies that lack the triplets of microtubules which characterize basal bodies in almost all other cells (10).
In colleters of the innermost stipule pair (P3) the cells have thin walls; dense cytoplasm; large nuclei; numerous mitochondria with well-developed cristae; dictyosomes
and smooth endoplasmic reticulum (SER) (Fig.
hirsuta root hairs, Ridge (1988) identified three vesicle types in the sub-apical region: pyriformis vesicles found primarily in the apical dome; coated secretory vesicles located anywhere between the nucleus and the tip; coated vesicles [these were also described by Bonnett and Newcomb (1966) and Newcomb and Bonnett (1965)] associated with dictyosomes
and the plasma membrane, in regions of cytoplasm away from the apical dome.