Growth and Heterocyst Production in Anabaena cylindrica Lemm

Abstract

A study has been made of the cytology of the heterocysts of Anabaena cylindrica Lemm. at different stages during the growth of this alga in culture. The techniques used include that of Feulgen, a modified Sakaguchi test for arginine derivatives, ultra-violet photomicrography, and micro-incineration. It has been shown that the formation of a heterocyst begins with the mobilization of material so that its protoplasm becomes homogeneous. The protoplast eubquently becomes depleted of all materiala demonstrable by the methods used. At intermediate stages in development substances become concentrated near the connexions of the heterocyst and a central transverse zone, retaining material longer than the reat of the protoplasm, becomes apparent. The structure and development of heterocysts is discussed.