The influence of Al and Ca on the growth, in axenic culture, of three ectomycorrhizal fungi associated with jack pine (Pinus banksianaLamb.) was examined. Isolates ofHebeloma crustuliniforme(St. Amans) Queacute;l.,Rhizopogon rubescens(Tul.) Tulasne, andSuillus tomentosus(Kauff.) Singer, Snell amp; Dick were obtained from basidiocarps collected in jack pine stands of different ages. Basidiocarps and the soil surrounding them were analyzed for Al and Ca, as well as other elements. Each fungal species was grown for 4 weeks in nutrient solutions containing 37, 185, 370, or 740ensp;mu;M Al combined in a factorial design with 25, 125, 250, or 500ensp;mu;M Ca and maintained at pH 3.8. Growth of all three fungal species was reduced at 370ensp;mu;M Al. Significant interaction was found between fungal species and Al treatment for all six elements measured in mycelial tissue. Stepwise increments in external Al concentration resulted in reduced mycelial concentrations of Ca, Mg, and K, and increased mycelial concentrations of Al, P, and Fe inH.crustuliniforme. High external Al levels resulted in reduced mycelial concentrations of all elements measured except Al and P inR.rubescens. In contrast, forS.tomentosusthe same external Al levels increased the mycelial concentrations of all elements except Ca. The response of the three ectomycorrhizal fungi to Ca also differed. Growth ofH.crustuliniformewas stimulated by stepwise increments in external Ca concentrations from 25 to 500ensp;mu;M. Increments in calcium had no effect on the growth ofR.rubescens. High external levels of Ca acted synergistically with high external Al concentrations to reduce growth byS.tomentosus. Unlike the other two species, the response ofS.tomentosusto Al and Ca could not have been predicted from the soil and basidiocarp analyses. Alterations in Ca to Al ratios of soils may influence the succession of ectomycorrhizal fungi on conifer root systems.Key words: ectomycorrhizae, jack pine, aluminum, calcium, basidiocarps.
展开▼
