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- Title
AN INVESTIGATION OF THE CELL WALL COMPONENTS OF <em>ACTINOCYCLUS SUBTILIS</em> (BACILLARIOPHYCEAE).
- Authors
Andersen, R. A.; Medlin, L.K.; Crawford, R.M.
- Abstract
The frustule of Actinocyclus subtilis (Greg.) Ralfs has been examined in detail with light and electron microscopy. The complex valve structure can only be appreciated fully by means of thin-sections. The loculate areola is closed to the inside by a basket of organic material, which is supported by a system of radiating, lightly silicified ribs. The basket is easily destroyed by acid cleaning, thus leaving an open hole (foramen). The loculus is connected to the outside by a system of interconnecting channels, whose external openings are too small to be resolved by the SEM. Between the locules of the valve face is a complex system of bullulae. The labiate processes are slightly tilted from the vertical axis vis α vis the valve mantle. Fibrillar material and mucilage are present within each labiate process, observations not reported previously. Histochemistry indicates that acid mucopolyaccharides are present within the lumen of the labiate process. We propose that the secretion of mucilage is related to the rotational, but directed movement noted in this centric diatom. The pseudonodulus is a solid silica plate subtended on the inside by a disc of organic material external to the cytoplasm. The relationship between Actinocyclus, Hemidiscus, Roperia, Charcotia and Azpeitia is discussed based on these new findings of valve morphology. Also the relationship between the families Hemidiscaceae and Coscinodiscaceae is discussed.
- Subjects
ACTINOCYCLUS; DIATOMS; PLANT cell walls; DIATOM frustules; HEMIDISCACEAE; CENTRALES
- Publication
Journal of Phycology, 1986, Vol 22, Issue 4, p466
- ISSN
0022-3646
- Publication type
Article
- DOI
10.1111/j.1529-8817.1986.tb02490.x