Altered Nitrogenous Pools Induced by the Azolla-Anabaena Azolla Symbiosis

The free amino acid and ammonia pools of Azolla caroliniana were analyzed by quantitative column chromatography on columns capable of separating all of the nitrogenous constituents normally found in physiological fluids. Comparisons were made of plants containing symbiotic algae and grown on nitrogen-free media, plants grown on media containing nitrate, and algae-free plants also grown on nitrate media. The major feature of the data was a very high level of intracellular ammonia found in plants which contain N(2)-fixing algal symbionts. In addition to the more usual amino acids, serine and cystathionine were found in the free amino acid pool.