ISSN:
1615-6102
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Differentiation of immobile zoospores into future basal cells of vegetative filaments ofOedogonium is described. Once flagella are shed, the constriction disappears from around the dome which soon starts pushing out rhizoid(s); these may become long and/or numerous if cells cannot attach themselves to a substrate. The flagellar apparatus, including the basal bodies, slowly disintegrates within the dome without involving lysosomal structures. A wall is secreted around the elongating cell; several distinguishable types of vesicular components are discharged into it at the dome. Some are derived from hypertrophied golgi bodies, and others from the numerous basal particles (characteristic of zoospores) which had undergone changes in appearance and cytochemical reactivity. The growing rhizoids flatten and extend, finger-like, across the surface of flat substrates, or wrap around vegetative filaments of other alga. The thick holdfats wall is secreted around them, usually forming a structure like a flattened cone; meanwhile the holdfast's interior containing much endoplasmic reticulum becomes increasingly subdivided into a labyrinth by ingrowing folds of wall. Microtubules and extensive arrays of smooth reticulate membranes are present near these walls. The hypertrophied golgi bodies in the holdfast soon revert to their usual smaller size. Eyespots degenerate, and the apical wall develops the circumferential discontinuity which will be the site of the future ring. In unattached germlings, the large accumulation of rough endoplasmic reticulum in the holdfast often shows evidence of breakdown, being replaced by masses of smooth membranes or else homogeneous “souplike” cytoplasm devoid of membranes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01279208
