NOZAKI H, KUROIWA T

MORPHOLOGY AND SEXUAL REPRODUCTION OF GONIUM-MULTICOCCUM (VOLVOCALES, CHLOROPHYTA) FROM NEPAL
PHYCOLOGIA 30 (5): 381-393 SEP 1991

Abstract:
Strains of Gonium (Volvocales, Chlorophyta) were isolated from a soil sample collected in Nepal. They generally produced 16- or 32-celled colonies with multipyrenoid cells, but 8-celled colonies were occasionally observed. Vegetative morphology observed by light and electron microscopy and embryogenesis indicated that this entity is referable to multicoccum Pocock, but differs in some respects from the original description of G. multicoccum. In addition, sexual reproduction in these Nepalese strains was unusual with regard to gametic union and zygote germination. Isogametes lacked tubular mating structures (mating papillae), which are seen in the anterior region of the gametes in other Gonium species as well as in other isogamous genera of the volvocacean and astrephomenacean algae. Plasmogamy was initiated by direct attachment between the surfaces of the two gametic protoplasts. The attaching sites were apparently randomly located on the gametic protoplasts. The germinating zygote usually gave rise to four separate biflagellate gone cells, rather than a colony of four.

SAKO Y, SHRESTHA K, UCHIDA A, et al.

ISOZYME ANALYSIS OF MATING POPULATIONS OF GONIUM-PECTORALE (CHLOROPHYTA)
J PHYCOL 27 (2): 309-315 APR 1991

Abstract:
Intraspecific variation among 36 strains of the freshwater alga Gonium pectorale Muller (Chlorophyceae) isolated from three geographically different locations in Tibet, Nepal, and Japan was investigated by isozyme analysis. Variation in isozyme patterns of eight enzyme systems (malate dehydrogenase, glutamate dehydrogenase, tetrazolium oxidase, lactate dehydrogenase, octanol dehydrogenase, xanthine dehydrogenase, phosphoglucomutase, and malic enzyme) of axenic and clonal cultures was revealed by polyacrylamide gel electrophoresis. Unweighted average linkage clustering, based on Jaccard's similarity coefficient, illustrated the high similarity between most strains from Nepal and all strains from the Ryukyu Islands (Japan). However, there was relatively low similarity between strains from Tibet and those from Nepal and Japan. Strains from the Ryukyu Islands (Japan) grouped into two clusters, and most Nepalese strains formed a single cluster, but Tibetan strains were heterogenous.