Antifungal activity of Rhizobium

Antifungal activity of three different Rhizobium isolates was tested against eight different fungi. Some of these fungi are potential phytopathogens on legumes. Inhibition zones were observed in several cases. Similar results were obtained with the cell-free extract of the media on which Rhizobium had been grown.

Les champignons et leur écologie dans un sol ensemencé en trèfle rouge

The ecology of fungi in a soil seeded with red clover has been investigated. The dilution plate technique was used with a medium supplemented with streptomycin sulfate. A total of 67 species belonging to 43 genera were recovered. The most frequently isolated species were in decreasing order: Pénicillium spp., Coniothyrium spp., Trichoderma viride, Gliocladium roseum, Rhizopus nigricans, Fusarium oxysporum, and Fusarium culmorum. Ten species of fungi not previously reported in Canada were isolated from soils.The ecology of fungi is discussed in relation to soil moisture content, soil texture, depth of soil sampling, and period of the year.

Effect of carbon and nitrogen nutrition on growth and sporulation of Trichoderma viride Pers. ex Fries

Three isolates of Trichoderma viride Pers. ex Fries were grown in liquid cultures. The isolates grew best on media containing glucose, sucrose, cellobiose, and mannitol.Asparagine and ammonium nitrate proved to be the best sources of nitrogen for the three isolates although isolate 1503 did not show any significant preferences for the five sources of nitrogen. The amounts of carbon and nitrogen in the basal medium significantly influenced the growth of the three isolates. However, the addition of asparagine alone did not produce a better growth than in the control. There is no correlation between sporulation and dry weight of culture, the amounts of carbon in the medium, and C/N ratio. Implications of the findings are briefly discussed.

FORMATION OF MICROENDOSPORES IN CERATOCYSTIS ULMI (BUISM.) C. MOREAU

A morphological study of several isolates of Ceratocystis ulmi has revealed that spores and hyphae of this fungus contain minute cytoplasmic particles that behave like spores (microendospores). The different stages of development of these microendospores are described and some implications of the findings are briefly discussed.