Fungal species and element type modulate the effects of environmental factors on the concentration of potentially toxic elements in mushrooms.

Numerous edible mushrooms accumulate Potentially Toxic Elements (PTE), such as cadmium, mercury, and lead, within their sporocarps. This accumulation poses a potential risk of poisoning for humans and is influenced by factors such as the mushroom species, type of element, and the level of industrialization in the region. In our study, we investigated how soil and tree stand characteristics, including C/N ratio, pH, tree diversity, canopy cover, and the proportion of deciduous trees, influence PTE concentration in mushrooms. We collected edible mushrooms from 20 plots situated in the Bialowieza Primeval Forest, one of Europe's best-preserved lowland forests. Plots varied in terms of tree species composition, with other factors minimized. We used ICP-MS (Inductively Coupled Plasma - Mass Spectrometry) technique to analyze the concentration of eight PTE (Ag, As, Cd, Ni, Pb, Sb, Sr, Tl) in eight edible mushroom species (M.procera, L.perlatum, R. butyracea, R.cyanoxantha, R.heterophylla, L.vellereus, A.mellea, and Xerocomellus chrysenteron). Our research revealed that the presence of the effect of specific factors on concentration of PTE and its direction depends on mushroom species and type of PTE. The proportion of deciduous tree species and pH of the topsoil layer emerged as the most influential factors affecting PTE concentration in mushroom samples. Tree species richness in the canopy layer did not affect PTE concentration in mushrooms, except for the concentration of Pb in X. chrysenteron. We observed a consistent profile of PTE concentration in mushrooms with similar ecological roles (ectomycorrhizal, saprotrophic, parasite mushrooms) and from comparable phylogenetic affinities.

Factors affecting composition of fatty acids in wild-growing forest mushrooms.

The importance of mushrooms as a food source is continually increasing. To investigate how environmental factors affect the nutritional value of mushrooms, we harvested them in eastern Poland, south-central Germany, and northwestern Belgium in plots with similar environmental conditions but varying in tree species composition and richness. We used gas chromatography-mass spectrometry (GC-MS) to analyze the fatty acid (FA) content of the mushrooms. Fungal species identity explained the largest part (40%) of the total variation in FA concentration and composition. Environmental factors accounted for 1-12% of variation. The concentration of FA, especially saturated fatty acids, decreased with increasing understory cover and increasing nitrogen concentration in the topsoil. The effect of tree species richness or tree species identity was negligible. Our results suggest that the nutritional value of mushrooms depends mainly on the species identity of fungi, but that their FA content is slightly higher in forests with less undergrowth and in nitrogen-poor soils.