1967 Volume 13 Issue 1 Pages 53-61
The present observation indicates that, besides the nitrogenous compounds, other biologically active cell constituents like vitamin B12 and auxins may also appreciably contribute to the fertilizing action of the nitrogen-fixing blue-green algae. Of the various intracellular amino acids of Cylindrospermum muscicola, cystine, tyrosine and phenylalanine seem to be available to the rice plants. The alga can synthesize vitamin B12 active compounds, the yield of which was about 1.2 to 1.5μg/g dry weight of the alga. The synthesis of these compounds was promoted by the addition of cobalt salt. The alga also contains interconvertible auxin-like substances which stimulate the root growth of rice seedlings.