Accumulation of reserve polymers by Nostoc muscorum CALU 304 cells grown in mixed culture with plant tissue

In cells of the cyanobacterium Nostoc muscorum CALU 304 grown in mixed cult ure with rauwolfia callus tissue, morphological and functional changes indu ced by the plant tissue were studied. Due to the effect of the plant partne r, cyanobacterial growth was stimulated under unfavorable conditions, heter ocysts evolved and nitrogenase activity was induced during incubation on ni trogen-containing medium, and reserve polymers accumulated. The results obt ained suggest that, in the presence of rauwolfia callus, the routine regula tion of nitrogen assimilation was altered in cyanobacterial cells. First, c yanophycin accumulated due to utilization of exogenous bound nitrogen; then , heterocysts evolved and nitrogenase activity appeared against the backgro und of high content of intracellular nitrogen.