Development, function and specificity of actinorhizae and mycorrhizae on Alnus jorullensis H.B.K. from Argentina

DOMÍNGUEZ DE TOLEDO, L.; NOUHRA, E.; MOLINA, R., BECERRA, A.

California, USA

Conferencia; Primera Conferencia Internacional de Micorrizas (ICOM); 1996

Universidad de California Berkeley

Alnus species are important components in many native forests. Alnus forms both N-fixing nodules (actinorhizae) as well as vesicular-arbuscular mycorrhizae and ectomycorrhizae. Such tripartite or tetrapartite symbioses contribute to succesful colonization of Alnus in nutrient poor or disturbed sites, with subsequent benefits to site quality. Alnus jorullensis occurs in the Andes of South America in wet montane habitats above 1300m. In three related studies we examined occurrence and function of root symbiosis of A. jorullensis in its native forests and following inoculation with forest soil, Frankia, and the ectomycorrhizal fungus Alpova diplophloeus native to A. rubra habitats in Oregon (USA): (1) Roots of A. jorullensis were collected from forests in Catamarca and Tucuman Provinces (Argentina). We describe two ectomycorrhiza types, presence of nodules and colonization by dark septate endophytes; (2) Seedlings of A. jorullensis were greenhouse in sterile soil and inculated with Oregon cultures of Frankia and spores of A. diplophloeus ectomycorrhizae became well developed; (3) Seedlings of A. jorullensis and A. rubra were grown in soil taken from beneath A. rubra and harvested at three times. Both Alnus species developed nodules and shared compatibility for three disctinct ectomycorrhiza types.