The effects of Eucalyptus globulus oils on fungal enzymatic activity
Canhoto, C.; Bärlocher, F.; Graça, M. A. S.
published: May 13, 2002
ArtNo. ESP141015401012, Price: 29.00 €
The effects of Eucalyptus globulus oils on enzymatic activities and growth of aquatic hyphomycetes were assessed. Culture supernatants of Flagellospora curta, F. penicillioides, Heliscus lugdunensis, Lemonniera aquatica and Lunulospora curvula were tested for activity against carboxymethylcellulose, pectin and xylan. Lipase and phenol-oxidase assays were performed on solid media. No lipase activity was detected in any of the species; eucalypt oils at concentrations up to 2.5 % inhibited the other enzymes of all species except H. lugdunensis. Fungal growth on malt extract agar was totally inhibited when colonies were exposed to oil vapours. We suggest that eucalypt oils contain compounds that limit fungal growth, both by interfering with degradative enzymes and by affecting mycelial viability. In streams, fungal invasion of eucalypt leaves proceeds mainly through stomata. Fungal growth through the leaf's mesophyll may be inhibited by the extended presence of oil vesicles, which could be partly responsible for the prolonged integrity of eucalypt leaves decaying in streams.