Studies of pathogenic and antagonistic microfungal populations and their potential interactions in the mycorrhizoplane of Norway spruce (Picea abies (L.) Karst.) and beech (Fagus sylvatica L.) on acidified and limed plots

摘要

A field trial was conducted in an 80-year-old Norway spruce (Picea abies) stand and a 140-year-old Fagus sylvatica stand during 1990-91 at Hoglwald, southern Germany, to investigate the connection between tree decline and root damage caused by soilacidification and an increase in pathogenic root colonizing fungi. The microfungal populations connected to the mycorrhizoplane of P. abies and F. sylvatica were investigated on P. abies plots that had been treated with acidified water or were limed anduntreated F. sylvatica plots. Eight microfungal species known as either pathogenic or antagonistic (Trichoderma viride, T. hamatum, T. polysporum, Cylindrocarpon destructans, Sesquicillium candelabrum, Mycelium radicis atrovirens, Tolyplocladium geodes and Oidiodendron maius), were isolated from the mycorrhizoplanes and their abundance in the 5 different plots compared. Acidification enhanced the frequency of Mycelium radicis atrovirens and Oidiodendron maius but reduced Trichoderma viride. Liming promoted Sesquicillium candelabrum and Cylindrocarpon destructans. Detailed analysis of the population patterns indicated that changes in the frequency of particular fungal species were caused not only by a shift in chemical soil factors but also by antagonistic interactions between the microfungi, thus reducing pathogenic attacks on rootlets.