庐山外生菌根真菌的分布

根据不同的季节对庐山林区的真菌进行了点与面的调查。共报道了庐山的外生菌根真菌１４属３１种，对它们发生时期、菌的生长习性和分布进行详细的报道。尤其它们的分布与海拔高度、植被类型和土壤类型息息相关，这为进一步对该林区森林生态系统中与这些菌类有关的物质转化和能量循环的探讨和研究提供了相关的依据。

Influence of Ectomycorrhizal Fungi on Absorption and Balance of Essential Elements of Pinus tabulaeformis Seedlings in Saline Soil

Pinus tabulaeformis seedlings were grown under a factorial design to measure biomass accumulation and P, Na and K concentrations of plants, with 3 different ectomycorrhizal fungus (EMF) strains (Boletus edulis, Xerocomus chrysenteron and Gomphidius viscidus) and two P treatments (with or without extra P). Growth and mineral nutrition of pine seedlings were stimulated by three EMF under salinity stress. Na concentrations were changed and plant K and P concentrations were increased significantly by EMF. Adding extra P made no difference in accumulation of seedlings biomass, and did not assist element absorption of plants. Although three strains of EMF can all enhance the tolerance of pine seedlings to salinity stress, they may utilize different mechanisms because of different performance in absorption of elements. The increased P and K accumulation and the balance of ion concentrations might be due to the enhanced tolerance of EMF-inoculated plants to saline conditions.

Mobilization of Inorganic Phosphorus from Soils by Ectomycorrhizal Fungi

Ectomycorrhizal(EM) fungi could form symbiosis with plant roots and participate in nutrient absorption; however, many EM species commonly found in forest soils, where phosphorus(P) concentration and availability are usually very low, particularly in tropical and subtropical areas, have not yet been investigated for their efficiencies to mobilize soil P. In this study, fungal growth, P absorption,efflux of protons and organic acids, and soil P depletion by four isolates of EM fungi isolated either from acidic or calcareous soils were compared in pure liquid culture using soil as a sole P source. Boletus sp. 7(Bo 7), Lactarius deliciosus 3(Ld 3), and Pisolithus tinctorius 715(Pt 715) from acidic and P-deficient soils of southwestern China showed higher biomass and P concentration and accumulation than Cenococcum geophilum 4(Cg 4) from a calcareous soil of Inner Mongolia, northern China, after 4 weeks of liquid culture. Oxalate, malate, succinate, acetate, and citrate concentrations in the culture solutions varied significantly with fungal species,and oxalate accounted for 51.5%–91.4% of the total organic acids. Organic acids, particularly oxalate, in the culture solutions may lead to the solubilization of iron-bound P(Fe-P), aluminum-bound P(Al-P), and occluded P(O-P) from soil phosphates. Fungal species also varied greatly in proton efflux, which decreased the culture solution pH and may dissolve calcium-bound P(Ca-P) in soil.This could be the reason for the increment of both inorganic P in the culture solutions and Olsen P in the soil when EM fungi were present. Total inorganic P, the sum of Al-P, Fe-P, O-P, and Ca-P, in the culture solutions was positively correlated with the total concentration of organic acids in the culture solutions(r = 0.918*, n = 5), but negatively with both the total inorganic P in soil(r =-0.970**, n = 5) and the culture solution pH(r =-0.830*, n = 5). These suggested variable efficiencies of EM fungal species to mobilize inorganic P fractions from soil, which could make EM trees to utilize inorganic P in the same way like EM fungi and adapt to the soils with various P concentrations and availabilities.

The role of soil-borne fungi in driving the coexistence of Pinus massoniana and Lithocarpus glaber in a subtropical forest via plant-soil feedback

Aims Plant–soil feedback(PSF)is a key mechanism that can facilitate tree species coexistence and diversity.Substantial evidence suggests that species-specific soil-borne pathogens around adult trees limit the performance of home(conspecific)seedlings relative to foreign(heterospecific)seedlings.However,the underlying mechanism remains largely elusive.Methods Here,we conducted a reciprocal transplant pot experiment using seedlings and from two tree species,Pinus massoniana and Lithocarpus glaber that are dominant and coexist in a subtropical,evergreen,broad-leaf forest in Gutianshan,Zhejiang Province of eastern China.We examined how seedlings from the two tree species responded to soils originating from underneath their own versus the other tree species,using a full-factorial design.Additionally,we added a fungicide(benomyl)to half of the pots to evaluate the role of soil-borne fungi on seedling growth.Important Findings We found that the seedlings from L.glaber grew better in soils that were collected from beneath the canopy of P.massoniana,while seedling growth of P.massioniana was not affected by soil origin.The addition of fungicide benomyl resulted in a shift towards more positive PSF effects for L.glaber,indicating that L.glaber seedlings performed better in their own soils than in soils from P.massoniana in the absence of fungi.Our findings highlight the importance of soil-borne pathogenic and ectomycorrhizal fungi in driving PSF,and indicate that PSF may promote the coexistence of two subtropical tree species by reducing the performance of L.glaber in own soils.

Gut passage of epigeous ectomycorrhizal fungi by two opportunistic mycophagous rodents

Mycophagists can influence fungal diversity within their home ranges by ensuring the continued and effective dispersal of spores from one site to another. However, the passage of spores through the digestive tract of vertebrates can affect the activity and viability of the spores ingested. This phenomenon has been rarely documented in opportunistic mycophagists consuming epigeous fungi. Using laboratory experiments, we investigated the activity and viability of spores of two epigeous ectomycorrhizal fungal species （Laccaria trichodermophora and SuiUus tomentosus） after passage through the digestive tract of two opportunistic mycophagous small rodents, the volcano mouse Peromyscus alstoni and the deer mouse P maniculatus. We found that passage through the gut of either species of rodent had a significant effect on spore activity and viability for both fungal species. The proportion of active spores （0.37-0.40） of L. trichodermophora in the feces of both species of rodents was less than that recorded for the control （0.82）. However, the proportion of active spores （0.644）.73） of S. tomentosus in the feces of each species of rodent was higher than in the control （0.40）. On the other hand, the viability of spores was lower （0.26-0.30 in L. trichodermophora and 0.604）.69 in S. tomentosus） for both fungi when consumed by either rodent relative to the controls （0.90 in L. trichodermophora and 0.82 in S. tomentosus）. These findings suggest that these rodent species may be effective dispersers of both epigeous fungi [Current Zoology 57 （3）： 293-299, 2011].