Effect of nutrients and aeration on O-2 evolution and photosynthetic pigments of Anaboena torulosa during akinete differentiation

The addition of a nitrogen (nitrate) and carbon sources (acetate, citrate a nd fructose) and phosphate deficiency (nitrate medium deficient in phosphat e) under unaerated conditions induced akinete differentiation in Anaboena t orulosa. Aerated cultures of this organism in these nutrients did not diffe rentiate akinetes. Oxygen evolution by aerated cultures was higher when com pared to unaerated cultures, which concurred with high chlorophyll content of aerated cultures. Nitrate nitrogen supported high phycocyanin content in unaerated cultures; phycocyanin and allophycocyanin contents were low unde r aerated conditions. The contents of phycocyanin, allophycocyanin, phycoer ythrin and carotenoids gradually decreased at the mature akinete phase. Und er aerated conditions, chlorophyll content rose and the content of all the pigments increased with the growth rate of the organism.