Karyotypic analysis of two algae species Scenedesmus incrassatulus Bohl. and Scenedesmus antennatus Bréb. (Chlorophyta, Chlorococcales)

Abstract

The karyotypes (number, morphology and size of the chromosomes) of two algae species of Scenedesmus genus, S. incrassatulus and S. antennatus, were studied. The karyotype of S. incrassatulus (n = 4) was asymmetric, characterized by two large metacentric, one large submetacentric and one small metacentric chromosomes. The karyotype assembly of S. antennatus (n = 6) reveals two metacentrics and four submetacentrics. This karyotype was symmetric. The general chromosomal formulae of both species, as well as the total average metaphase length of their haploid set are presented. The results of chromosomal studies of other related species are compared and discussed. Data from the karyotypic analysis showed that S. incrassatulus, S. antennatus and S. obliquus are separate biological species from taxonomical point of view.