Studies of some effects of volatile fungal metabolites on the growth and ecology of soil fungi and of plant pathogenic bacteria

al-Tamimi, Kamil Mehdi (1975) Studies of some effects of volatile fungal metabolites on the growth and ecology of soil fungi and of plant pathogenic bacteria. PhD thesis, University of Glasgow.

Abstract

The thesis reports an investigation of the effects of volatile metabolites produced by cultures of a range of species of Trichoderma on the growth of some other fungi in agar culture and on some bacteria in agar culture and in soil. The effects of the culture gases on other species of fungi could be accounted for by the amounts of carbon dioxide produced by the Trichoderma cultures in the conditions used. The differences between the effects of different species could be accounted for by differences in the rate of production of CO2 in the early stages of interactions. The amounts of acetaldehyde and of ethanol produced could also contribute to the effects in some conditions. No other metabolites were found in sufficient concentrations to affect the interactions; this does not discount the possibility of other unidentified metabolites contributing to the interactions in the conditions examined. Those identified were all primary metabolites; small changes in the environment might also result in differences in the production and concentrations of these constituents of the culture gas cloud. This could result in differences in their individual contributions to the total effects. The effects of the Trichoderma culture gases on five species of plant pathogenic bacteria were strongly affected by the medium and conditions in which the tests were carried out. The techniques did not reveal any effects of Trichoderma culture gases on bacterial growth on Bouillon agar or clay soil. In tests with authentic material, Erwinia tracheiphila was found to be inhibited by lower concentrations of primary gaseous metabolites than those needed to inhibit E. aroideae; but in these cases the inhibitory concentrations were greater than those found in Trichoderma culture gases. In other soil cultures the Trichoderma culture gases inhibited the bacteria. The inhibition was greatest on a loam soil and less on a sand, and greater with E.tracheiphila than with E.aroideae. By tests with authentic material in the concentrations found in Trichoderma culture gases, it was shorn that effects and the differences between the effects of gases from cultures of T.viride 1 and T.longibranchiatum WBC 4576 could be accounted for by the amounts of carbon dioxide present in the different conditions.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: S A Hutchinson
• Keywords: Microbiology, Soil sciences, Plant pathology
• Date of Award: 1975
• Depositing User: Enlighten Team
• Unique ID: glathesis:1975-72422
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 24 May 2019 15:12
• Last Modified: 24 May 2019 15:12
• URI: https://theses.gla.ac.uk/id/eprint/72422