A technique for dual vesicular-arbuscular endomycorrhizal/ectomycorrhizal infection of Eucalyptus in vitro.

A few species of plant, including Eucalyptus, bear simultaneously on their root system and even on the same root apex, more than one symbiotic microorganism. The development of techniques allowing mixed inoculations is an essential prerequisite for the study of interactions between different symbionts. A simple in vitro technique for rapid synthesis of dual vesicular-arbuscular endomycorrhiza/ectomycorrhiza on a single root apex of Eucalyptus seedlings is described. This technique was derived from the paper-sandwich technique for synthesis of ectomycorrhizas, and was modified to render it compatible with endomycorrhizal infection. Electron microscopy observations of dual endomycorrhiza/ectomycorrhiza showed both symbioses coexisting on the same apex, with no obvious sign of antagonism.