螺旋状群体を形成するAulacoseira ambigua （Grunow） Simonsen単藻培養株に見られた群体の形状変化

抄録

Colonies of Aulacoseira ambigua (Grunow) Simonsen is known to take two forms, linear and helical ones. Whether this difference is regulated by gene or environment, however, has not been known. We observed that helical colonies of A. ambigua became loose during cultures of isolated strains. Although helical colonies of this species observed in Lake Biwa are various in the helix pitch, such loosely wavy colony has not been observed yet. Our finding implies that the helical and linear colonies of this species can be environmental variations, but further research is needed to confirm this because the complete conversion from helical to linear colonies, and vice versa, have not yet been observed.