Influence of Environmental Factors on Ectomycorrhizal Infection in Axenically Cultured Eucalypt Seedlings

Abstract

The paper-sandwich technique for axenic synthesis of ectomycorrhizae was used to study the effect of various environmental factors on mycorrhizal formation by eucalypt seedlings. This technique involves growing plant roots and fungus separately, then bringing them together in a way which immediately initiates infection. Altering either temperature or the carbohydrate status of the fungus markedly affected the proportion of root apices converted to mycorrhizae. However, altering the light regime or nitrogen and phosphorus availability within wide limits did not affect the proportion of root apices converted to mycorrhizae. We conclude that infectibility of similar root apices remained constant throughout these experiments, and that those changes in the environment which affected the proportion of roots becoming mycorrhizal were mediated through effects on the colonisation capacity of the fungal partner.