Aluminium tolerance of different Paxillus involutus Fr. strains originating from polluted and nonpolluted sites

The caps of the sporocarps of P. involutus originating from the polluted site (Lubori) and from the control site in Kornik and Puszcza Nadnotecka accumulated high amounts of aluminium and revealed symptoms of bioconcentration. However in caps of the sporocarps from the control sites a lower amount of Al was accumulated than in caps from the polluted sire (Lubon). A significantly lower concentration of Al was found in stems of sporocarps originating from the special control site in Puszcza Nadnotecka. Mycelia of 11 strains isolated from sporocarps collected at the polluted and control sites were cultivated on a liquid medium containing 100 mg L-1 Al. All strains showed high bioconcentration of Al despite of the place of origin. In a subsequent experiment 10 strains of P. involutus originating from polluted soil and 8 strains derived from the control sites were grown in agar media containing 10, 100, 500 and 1000 mg/L-1 of Al. The radial growth rates during culture, the final colony dry weight and the metal tolerance indices calculated on the basis of measured parameters were determined. P. involutus strains appeared to be very tolerant to the presence of Al in the medium and were able to grow even at the highest Al concentration. Increasing aluminium level in the medium to different extent influenced growth of tested strains, however the site of the origin did not influence the response of P. involutus to aluminium: among 18 strains tested, the most tolerant were selected both from the polluted and from the unpolluted sites. The results are discussed with reference to the high intraspecific variability of different physiological features of the ectomycorrhizal fungus P. involutus.