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COMPARATIVE CYTOLOGY AND TAXONOMY OF THE ULVOPHYCEAE. IV. MITOSIS AND CYTOKINESIS IN ULOTHRIX (CHLOROPHYTA)
Author(s) -
Sluiman Hans J.,
Roberts Keith R.,
Stewart Kenneth D.,
Mattox Karl R.
Publication year - 1983
Publication title -
acta botanica neerlandica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0044-5983
DOI - 10.1111/j.1438-8677.1983.tb01711.x
Subject(s) - chlorophyta , cytokinesis , botany , biology , algae , cell , cell division , biochemistry
SUMMARY Some observations on the cytokinetic and mitotic mechanism in the filamentous green algae Ulothrix zonata (Weber & Mohr) Kützing and U. tenuissima Kützing are presented. The general pattern of division appears to be similar in both species, and includes a precocious cleavage furrow formed at late interphase. Cross wall formation is not completed until telophase. By late prophase the centriole pair has duplicated, and each daughter pair migrates to a position distinctly lateral to the spindle poles. As soon as the daughter nuclei have separated, formation of the new septum is completed by coalescence of presumably Golgi derived vesicles in the plane of the pre‐mitotically developed cleavage invagination, so there is no ingrowth of the furrow itself. A phycoplast as typically found in certain other filamentous green algae (e.g., Stigeoclonium ) is not formed. A comparable division mechanism has been reported previously in four cases, i.e., in Ulva, Pseudendoclonium, Trichosarcina , and in an alga of uncertain identity (UTEX strain LB 653). It is concluded that these taxa are related organisms, and can be referred to as Ulvophyceae sensu S tewart & M attox . The taxonomic status of a number of doubtful species of Ulothrix is discussed in the light of both light microscopical and electron microscopical evidence.