In the former copper shale mining district of Mansfeld, central Germany, weathering of slag heaps and dumps resulted in groundwater, lakes and streams with extremely high heavy metal and metalloid concentrations (Zn up to 2.6 g l -1; Cu, Pb, Cs, Cd, As up to 13 mg l -1 ). We followed decomposition of Alnus glutinosa leaves in 2 streams, one with a high (H4) and one with a moderate (H9) load of these metals. In H9, mass loss closely followed an exponential decay curve (k = 0.055 d -1 ); in H4, leaf mass remained constant after a very rapid initial decay (k = 0.12) during the first 4 wk. Fungal biomass, estimated by ergosterol measurements, reached values of up to 1.1% (H9) or 0.36% (H4) of total detrital mass, corresponding to 6 and 2%, respectively, of maxima reported from nonpolluted streams. Conidium production by aquatic hyphomycetes was reduced to 10% (H9) and 0.01% (H4) of highest literature values. After 4 wk of stream exposure, leaves had greatly increased levels of As, Cu, Fe, Mn (both streams), Pb and Zn (H4). Gammarus fossarum preferred leaves that had been conditioned in the stream for 2 (H9) or 4 (H4) wk over unconditioned leaves.

Eighteen species of endophytic fungi were isolated from bark, stem and leaf segments of five medicinal plant species growing within the Kudremukh range in the Western Ghats of India. The dominant endophytic fungal species isolated from these plant species were Curvularia clavata, C. lunata, C. pallescens and Fusarium oxysporum. The highest species richness as well as frequency of colonization of endophytic fungi was found in the leaf segments, rather than the stem and bark segments, of the host plant species. The greatest number of endophytic fungal species were found within Callicarpa tomentosa (11 species), whereas Lobelia nicotinifolia harbored the lowest number of fungal endophytes (5 species). This study provides evidence that fungal endophytes are host and tissue specific.

1. At two organically polluted sites in the River Nethravathi, banyan and eucalypt leaves were colonized by one or two species of aquatic hyphomycetes. A total of three or four species were identified at the two sites in samples of water and naturally occurring leaves. 2. Spore production from stream‐exposed leaves by aquatic hyphomycetes was lower by a factor of up to 1 million compared with an earlier study in geographically close but unpolluted streams. 3. Exponential decay rates and loss rates of phosphorus and calcium, were not statistically different from an earlier study in unpolluted streams. Nitrogen increased during decomposition more slowly in the current study. 4. The microbial community on both leaves released enzymes active against starch, pectin, cellulose and xylan. 5. Banyan leaves conditioned for 12 weeks were more palatable to the gastropod Notopala sp. than unconditioned leaves. 6. Together with earlier data from unpolluted streams, the study provides evidence that organic pollution severely restricts diversity of aquatic hyphomycetes and their reproductive output, but does not have an equally strong effect on ecological functions generally associated with this group.

Altogether fifteen species of endophytic fungi were recovered from surface sterilized leaf, stem and bark samples collected from eight medicinal plant species sampled in three different locations of the Western Ghats of India. Ethyl acetate extracts of fermentation cultures of these fungi were tested for the production of antimicrobial compounds using a panel of four bacterial strains and Candida albicans. From fifteen species, eight species of endophytes revealed the production of antimicrobial compounds. Partially purified extracts from solid state fermentation of Alternaria sp., Nigrospora oryzae and Papulospora sp. showed inhibitory activity against both Gram‐positive and Gram‐negative bacteria. In addition, extracts of Alternaria sp., inhibited the growth of Candida albicans. Extracts of Alternaria sp., Nigrospora oryzae and Papulospora sp. are promising enough to deserve further purification and characterization.

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