Rock phosphate effect on English mint (Mentha piperita L.) grown on steamed perlite:vermiculite (1:1, v:v) substrate, with and without rock phosphate, was evaluated in greenhouse experiments. Five treatments were carried out by inoculation with an arbuscular mycorrhizal fungus Glomus mosseae and a phosphorus solubilizing microorganism Penicillium thomii. Plant aerial biomass, phosphorus concentration in plant tissue, and P available in the substrate, were evaluated upon two harvests. After the first harvest, plant aerial biomass did not show significant differences between treatments using rock phosphate as fertilizer, although P content in plants inoculated with P. thomii was higher. The second harvest revealed a higher biomass and plant tissue P content in treatments inoculated with G. mosseae. P. thomii increased P available in the substrate, whereas in the absence of G. mosseae, it did not enhance plant tissue P content. Mycorrhizal colonization was not affected by P. thomii. Microbial inoculation effect on English mint growth was also evaluated. The microbial effect was positive in all treatments when compared with the control without rock phosphate.

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The species that characterized the fungal communities in the leaves of each of the trees were found to be different. The type of substrate had a stronger influence in determining the composition of the fungal community in both types of forests.

To get a better insight into the physiological capabilities of Ciliochorella buxifolia, the most frequent fungus occurring on Scutia buxifolia leaf-litter in a native forest from Argentina, its in-vitro ability to use 10 carbon sources and to produce extracellular enzymes, including its response to tannic acid and to the addition of a water-soluble fraction of Scutia buxifolia leaf-litter, was analyzed. Growth, colony morphology and extracellular enzyme activity as well as differentiation of pycnidia were a function of the C substrate. The fungus responded to the presence of tannic acid in a range between 0.001 and 0.1% (w/v), by increasing growth, but higher phenol concentrations like 0.5% were inhibitory. The activity of extracellular oxidative enzymes increased with the concentration of tannic acid. Furthermore, the fungus showed extracellular laccase and peroxidase activity, being the former increased by water-soluble fraction in association to pycnidia development. Based on these results, Ciliochorella buxifolia is a fungus growing on Scutia buxifolia leaf-litter that is able to metabolize soluble phenolic compounds, which triggers the synthesis of extracellular oxidative enzymes possibly involved in sporulation and detoxification reactions.

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