二角盤星藻二角變種單細胞形成之探討

Abstract

群落形綠藻二角盤星藻二角變種Pediastrum duplex Meyen var. duplex Meyen在實驗室培養和在自然水域中都很容易形成單細胞。培養基中的離子濃度太高或太低，高溫（34至35℃），弱光以及劇烈攪拌都會增加單細胞的比率。培養基中的氮、磷濃度會影響藻種的生長速率及單細胞的形成。單細胞之生長速率和光合作用速率都比群落者低，顯示單細胞的形成可能是藻種適應不良環境的一種策略。藻種用SDS、EDTA、pronase、纖維素?及果膠?處理時，可以產生單細胞；遊走孢子用ruthenium red染醣類及用coomassie blue染蛋白質時，均呈正反應。顯示游走孢子排列成群落時，彼此有識別物質，此識別物質可能是一種醣蛋白。當環境不良時，可能此醣蛋白不能合成或其性質會受到改變，使得遊走孢子彼此不能識別；或者是細胞間的連接物質不能合成，使得細胞不能相互連接，而形成單細胞。

The colony-forming Pediastrum dupelx var. duplex (strain 2060) easily forms unicell under cultural as well as natural condition. The culture conditions of extremely high or low ion concentration, higher temperature than 33 C, lower intensity of illumination and vigorous agitation might enhance the yield of unicell. The concentrations of N and P in culture medium might influence the growth rate of this alga and also the formation of unicell. The formation of unicell was considered to be an adaptation of this agla to stress environment. The unicells were characterized by the lower growth rate and lower photosynthetic rate than colony cells. The treatment of cells with SDS, EDTA, pronase, cellulase and pectinase might give rise to a high yield of unicell. Zoospores show positive reaction to ruthenium red and coomassie blue staining. These implied that the recognition substance enabling zoospores to arrange correctly in the vesicle might be a glycoprotein. It was proposed that the unicell formation was due to the failure of zoospore recognition, which was possibly resulted either from the inhibition of the glycoprotein synthesis or from the denaturization of existing glycoprotein.