Effects of liming on ectomycorrhizal fungi infecting Pinus sylvestris L.: III. Saprophytic growth and host plant infection at different pH values in unsterile humus

Five ectomycorrhizal fungi were studied in relation to the effects of applications of lime and wood ash to the growth substrate. Growth and survival of inoculated fungi in unsterile humus and relative root colonization frequency by inoculated and indigenous ectomycorrhizal fungi were measured. Growth of the fungi was tested in Petri dish systems with humus taken from a field site treated with lime and wood ash. The infection potential of the fungi was tested by introducing Pinus sylvestris L. seedlings into the growth systems. Paxillus involutus (Fr.) Fr. was the only fungus affected both by the pH increase, and by the different treatments applied, in all aspects of its ecology tested (growth and survival in humus, infection potential and competitive ability). No other fungus grew saprophytically, but they showed the similar changes in infection potential in response to pH whether lime or ash had been used.