Physiological basis of the pattern of vegetative growth of a blue-green alga.

Abstract

Fragmentation of algal filaments results in a stimulation of heterocyst formation, both absolutely and relative to cell division. This appears to be due neither to release of substances promoting heterocyst formation nor to such other effects of fragmentation as injury. Apparently, the spacing of heterocysts during normal vegetative growth of the alga is caused by heterocysts inhibiting nearby vegetative cells from differentiating into heterocysts.