Production of Cytokinin-like Substances by Cylindrocarpon destructans (Zins.) Scholt. Isolates Pathogenic and Nonpathogenic to Fir (Abies alba Mill.) seedlings

The production of cytokinin-like substances by different strains of Cylindrocarpon destructans either pathogenic or non pathogenic to fir (Abies alba Mill.) was studied. The cytokinins were extracted from the fungal culture media and separated by means of column chromatography. The biological activities in different fractions were assayed by callus growth of soybean (Glycine max Merill var. Acme). The amount of these substances was calculated on the basis of fresh weight of callus obtained from cultures containing authentic cytokinin. Cytokinin-like substances were detected in 5 of 6 pathogenic isolates tested and in 2 of 5 non-pathogenic isolates. On the basis of their occurrence in particular column fractions, most of the substances seem to be identical or similar to zeatin and zeatin riboside. In addition the fungi studied produced other, not identified cytokinin-like substances. The synthesis of Ri P can not be excluded. However the method applied did not allow to separate Ri P from zeatin and zeatin riboside.