Physiological properties of planktic species of Anabaena (Cyanobacteria) and their taxonomic value at species level

Fifty axenic strains of planktic Anabaena were determined for their physiological growth characteristics, including growth temperature range, salinity tolerance and heterotrophic ability. The taxonomic value of these physiological properties was evaluated by combining with their morphological characteristics. Except for A. affinis LEMMERMANN, all species showed good correlation between the morphological and growth temperature characteristics. A. affinis could be distinguished into two groups by temperature characteristics. An examination of salinity tolerance showed that most species could grow in salinity up to 1/5 (0.78% of salinity) or 1/3 sea-water medium (1.28% of salinity). Two species (A. solitaria and A. circinalis) grew only up to 1/10 sea-water medium (0.43% of salinity). None of planktic species ofAnabaena grew either in dark with addition of organic substances such as organic acids and sugars, or in the light with 3'-(3-4-dichlorophenyl)1', 1'-dimethyl urea (DCMU) and the above organic substances. The newly established species A. eucompacta Li et WATANABE was shown to have distinctly different temperature and salinity properties from the morphologically similar species, A. compacta (NYGAARD) HICKEL.