Due to the small number of studies on the role of coumarins in associative symbiotic relationships, some aspects of the infl uence of synthetic coumarins on the physicochemical and cultural properties of Azospirillum baldaniorum Sp245 were studied for the fi rst time. To reveal the role of hydroxylation in position 7 of the fused aromatic ring – 1-(2-oxo-2H-chromen-3-yl)butan-1,3-dione, comparative studies of the eff ect of the original and hydroxylated coumarins on the culture of a model strain of azospirilla were carried out.
