Effect of volatile substances from Origanum majorana and Ocimum basilicum on spore respiration and germination of some soil fungi.

Oxygen uptake by the spores of Fusarium moniliforme, F. oxysporum, F. semitectum, F. solani, Mucor racemosus and Trichoderma viride was increased in the presence of volatile substances extracted from Origanum majorana and Ocimum basilicum. This increase was greater in the presence of volatile substances from O. basilicum than O. majorana, except in the case of F. semitectum where the reverse was true. A drop in the RQ of all the germinating spores was observed in the presence of these substances. Volatile substances from O. majorana reduced the spore germination of M. racemosus whereas the spores of T. viride were stimulated to germinate. Volatile substances from O. basilicum stimulated the spore germination of M. racemosus whereas T. viride spores were not affected.