Light and electron microscopic studies on the development and liberation of Janczewskia gardneri Setch. spermatia (Rhodophyta)

Abstract

Jallczewskia spermatia occur in conceptacles and are formed by spermatangial mother cells that originate directly from the inner conceptacular cell layer or from uniseriate filaments. Each spermatangial mother cell produces several spermatangia. Young spermatia are enclosed within an electron dense spermatangial wall and are connected to their respective mother cells by a small septal plug. Reduced chloroplasts are present in the mother cells and in some developing spermatia. As the spermatia mature, the spermatangial wall gelatinizes at the apex of the s!)er matangium. Subsequently or concomitantly a two-layered spermatial wall forms which ruptures the sperm a tangium-mother cell pit connection. Rough endoplasmic reticulum aggregates in the posterior end of the spermatium to form spermatial vesicles containing fibrillar material, whereas dictyosome vesicles contribute to the fibrillar material accumulation in later stages. Shortly before or after release from the spermatangial mother cells, the spermatial vesicle becomes extracytoplasmic and a three-layered spermatial wall is formed which gelatinizes and expands to form a mucilage layer that surrounds the spermatia. The pre·fertilization, released spermatia lack a distinct wall, are spherical and possess an intact interphase nucleus, starch grains, numerous dictyosomes, and electron dense bodies of unknown function.

Morphological and photosynthetic variations in the process of spermatia formation from vegetative cells in Porphyra yezoensis Ueda (Bangiales, Rhodophyta) and their responses to desiccation

“…The cell wall of the vegetative cells of P. yezoensis resisted staining and most ridges on the cell surfaces became smaller and flatter during the process of differentiation into a sperm cell, indicating that the cell wall becomes thinner as the differentiation process progresses. The tendency for cell size to increase may be evidence that the wall surrounding the newly formed spermatia in P. yezoensis is an extension of the spermatangial mother cell wall (Kugrens 1974;Kim and Fritz 1993;Delivopoulos 2000). The cell walls appear to become thinner, and the cell surface flatter as the differentiation process progresses (Figs.…”

Fibrous vacuole associated organelles (FVAOs) in the Florideophyceae: a new interpretation of the ‘appareil cinétique’

“…The most probable origin is ER since ER is abundant and dictyosomes are not present in the dev e lop mental stage in which the FV AOs are fi rst de tected. Although they did not anticipate the com plexity of the FVAO, Kugrens (1974) and Young (1977) suspected that the 'appareil cinetique' was made up of ER, and Simon-Bichard-Breaud (l972b) noted that the 'crypte flagellaire' was produced fr om ER. Not only is the derivation of the organelle different fr om that expected of a flagellum, but it is also not composed of micro tubules nor obviously associated with them.…”

“…A number of workers began investigations to determine if the structures observed in B. hamifera spermatangia were present universally in red algal male repro ductive cells and whether the 'appareil cinetique' was indeed a flagellum. Even though the over whelming conclusion was that the structures were not routinely present, that the 'appareil cine tique' was not a flagellum and that, therefore, the 'crypte flagellaire' was not a specialized structure fo r containing a flagellum (Kugrens, 1974;Ku grens & West, 1972;Peel & Duckett, 1975;Pey riere, 197 4;Young, 1977), no consensus of opin ion as to the actual nature of the structures was reached. Consequently, the idea that flagella may be present in red algae has been perpetuated to this date (Margulis, 1981).…”

Ultrastructure of auxiliary and gonimoblast cells during carposporophyte development in the red alga Cryptopleura ruprechtiana (Delesseriaceae, Ceramiales, Rhodophyta)

“…The thalli were fixed immediately for 5h in 5% glutaraldehyde buffered by a mixture of equal amounts of 0.2 M Na-cacodylate buffer and seawater, which was adjusted to pH 7.0 (Kugrens 1974). The material was rinsed in decreasing concentrations of seawater in buffer and the final rinse was in 0.1M Na-cacodylate buffer.…”