Abstract: | Investigations of the content of inhibitory substances in some Poplar clones by thin-layer chromatography and the use of micro-organisms . Poplar leaves and stems (T 39 Wettstein Züchtung, T 213 PבForndorf’, T 217 Pבvernirubens’) from fertilized plots (P N K) and unfertilized plots were tested microbiologically and by thin-layer chromatography. Leaf extracts contained phenolic compounds which influenced the growth of Septotinia podophyllina Whetz. Stem extracts were found to contain other substances influencing the growth of Cryptodiaporhthe, populea (Sacc.) Butin. Fertilizing frequently influenced phenol production in bark extracts but only seldom in leaf extracts. |