The light influences the morphological aspects of algae Nostoc gelatinosum (Schousb) Elenk. and Cylindrospermum licheniforme (Bory) Kutz.. The dark regime generates the dimensional reducing of vegetative cells and heterocysts leading to the alteration of biomass, but spores do not suffer significant changes. Cultivating these algae to favorable conditions of natural and artificial light (continuous), results with launching the process of self-regulating dimensional of cells. The most beneficial sources of ilumination are natural and artificial light.
