A Taxonomic Study on Pediastrum tetras (Ehrenberg) Ralfs

Algae > Volume 9(2); 1994 > Article

Algae 1994;9(2): 145-152.

Mi Ran Kim, Yoon Kyung Chang

Department of Biology, Sookmyung Women's University

ABSTRACT

In order to re-examine the taxonomic characteristics of P. tetras group (P. tetras, P. tetras var. tetraodon) in Korea, 9 strains from 9 sites were isolated and cultured in laboratory. The morphological characteristics which have been applied for delimiting species or varieties of. P. tetras, i. e., degree of incision, cell from and size of processes in marginal cells were not stable enough to delimite species or varieties of P. tetras. All the strains examined produced colonies of both P. tetras type and P. tetras var. tetraodon type in the same culture. There were three types of cell wall ornamentations; wrinkled (st. 1,2,3,4,5), reticulate (st. 8,9), smooth (st. 7) and smooth and wrinkled (st. 6). Although the ultrastructures of the cell wall were variable among and within the strains, the wrinkles and reticulations are unique characteristics of P. tetras which can be applied to delimite this species from others. The 8 isozyme banding patterns of 9 strains examined were identical. Therefore, the 9 strains of P. tetras group were identified as one species, P. tetras (Ehrenberg) Ralfs.

Key words: Pediastrum tetras, taxonomy, morphology, ultrastructure, isozyme banding