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Reconsideration of the taxonomy of ellipsoidal species of Chlorella (Trebouxiophyceae, Chlorophyta), with establishment of Watanabea sen. nov.
Author(s) -
Hanagata Nobutaka,
Karube Isao,
Chihara Mitsuo,
Silva Paul C.
Publication year - 1998
Publication title -
phycological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.438
H-Index - 44
eISSN - 1440-1835
pISSN - 1322-0829
DOI - 10.1111/j.1440-1835.1998.tb00117.x
Subject(s) - pyrenoid , biology , botany , chlorophyta , algae , chlorophyceae , chloroplast , genus , annulus (botany) , cell wall , taxonomy (biology) , biochemistry , gene
SUMMARY Subcultures of SAG 211–9b and 1AM C‐211, ultimately derived from CCAP 211/9b, a strain isolated by Pringsheim in 1939 and identified as Chlorella sac‐charophila (Kruger) Migula were observed using light and electron microscopy. Their morphology proved to be basically identical. Both have two forms of cells, one (E‐form) narrowly to broadly ellipsoidal, the other (S‐form) ovoid to spheroidal. The cell wall of both forms is composed of a single smooth layer. The chloroplast of young cells is trough‐like or saucer‐shaped with a smooth margin, while that of mature cells is band‐ or cup‐shaped with deep incisions. The thylakoid lamellae are loosely stacked and neither form has a pyrenoid. Both types of cells are capable of producing autospores: eight to 16 in E‐form cells, two to four in S‐form cells. These morphological features are different from those of C. saccharophila , which has a pyrenoid and produces only one form of autospores. In the absence of any existing genus that includes Chlorella‐like algae with a simple cell wall, no pyrenoid, and two forms of mature cells and autospores, a new genus, Watanabea , is proposed with the type species W. reniformis .