Structure and Chemical Composition of the Spore Wall in Spirogyra (Zygnemataceae, Chlorophyceae)

Abstract

Spores of twenty species of Spirogyra were treated by acetolysis and viewed by scanning electron microscopy. The terms exo-, meso-and endospore should be maintained and based on chemical composition. Exo-and endospore are cellulose and/or pectin containing membranes. The mesospore is acetolysis-resistant and presumably contains sporopollenin.As basic pattern the spore wall in Spirogyra is composed of four layers: one exo-and endospore layer and two mesospore layers. The outer mesospore layer is mostly thin and hyaline, the inner layer thick and brown or yellow coloured and often sculptured. The germination suture is located in the inner mesospore layer. Some variations on this basic pattern were observed in Spirogyra bellis, S. cleveana and S. majuscula. Details of mesospore sculpture were observed and some taxonomic implications are discussed.The observed basic pattern is assumed to be valid for the Zygnemataceae as a whole.

Identity and phylogenetic placement of Spirogyra species (Zygnematophyceae, Charophyta) from California streams and elsewhere1

“…However, the mesospore sculpture of S. africana and S. fluviatilis studied by SEM was very similar (Simons et al. , Kim et al. ).…”

“…Notes: SEM observations showed a three‐layered mesospore with an outer layer thin and hyaline, and two inner, pigmented layers, of which the inner sublayer was finely reticulate (Simons et al. ). The inside of this inner sculptured mesospore layer had spongy structure under SEM (Simons et al.…”

“…The inside of this inner sculptured mesospore layer had spongy structure under SEM (Simons et al. ). According to Rundina () the mesospore of this species was poorly studied, and probably consisted of four layers.…”

SYSTEMATICS OF THE GENUS ZYGNEMA (ZYGNEMATOPHYCEAE, CHAROPHYTA) FROM CALIFORNIAN WATERSHEDS1

“…1982). The mesospore is known to contain the resistant sporopollenin (Ashraf and Godward 1980, Simons et al. 1982).…”

Induction of sexual reproduction in Spirogyra clones - does an universal trigger exist?

“…This procedure should enhance the sculptures of the spore walls. Some hypnozygotes were fixed in ethanol or Strasburger solution and treated mechanically in an attempt to separate the spore wall layers: the hypnozygotes were put on a slide and pressed slightly while moving the cover glass (SimonS et al 1982). Species identification was carried out using the three monographs of tranSeaU (1951), randhawa (1959), and kadlUBowSka (1984).…”