Changes in mineral composition of six strains of Pleurotus after substrate modifications with different share of nitrogen forms.

The chemical characteristics of substrate are one the most significant factors influencing the growth and development of cultivated mushroom species. The aim of this study was to determine the mineral composition of six Pleurotus species (P. cistidiosus, P. djamor, P. ostreatus, P. ostreatus var. florida, P. pulmonarius and P. sajor-caju) growing on three wheat straw substrates with the addition of agricultural fertilizer rich in ammonium and with addition of salt solution rich in nitrates. Significant differences in the concentration of Al, Ca, Cu, Ir, Ni, Ru, Sn and Te were observed in all substrates used in this experiment. Cultivation on chemically-enriched substrates did not result in changes in yield with the exception of P. sajor-caju, which had a lower yield when grown on ammonium-rich substrate. No macroscopic alterations in fruit bodies were observed for any species regardless of the applied substrate. A higher concentration of selected elements was not correlated with their higher content in particular mushroom species, or such a relationship was present only in selected mushroom species. The efficiency of element accumulation depends on their concentration in the substrate (positive values of r_s), although the mushroom species and the nitrogen form concentration may also have a significant impact (negative r_s values). The obtained results show that cultivation of different Pleurotus strains on substrates enriched with a different share of ammonium and nitrate may cause changes in their mineral composition in spite of the similarity in the concentration of the majority elements in substrates. [ABSTRACT FROM AUTHOR]