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Development, function and specificity of actinorhizae and
mycorrhizae on Alnus jorullensis H.B.K from Argentina
talk/poster session 7
DOMINGUEZ de TOLEDO1, L.;E. NOUHRA1,
R. MOLINA2 & A. BECERRA3
1Instituto Multidisciplinario de Biologia
Vegetal. Casilla de Correo 495. 5000, Cordoba, Argentina
2USDA Pacific Northwest Research Station,
Forestry Science Laboratory, Corvallis, OR. 97331
3Fac. Cs. Ex. Fis. y Nat. U.N.C. Av. V.Sarsfield
299. 5000, Cordoba, Argentina
ICOM1 Abstract
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 1300 m. 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 grown in sterile soil and
inoculated with Oregon cultures of Frankia and spores of A.
diplophloeus. N-fixing nodules and 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
distinct ectomycorrhiza types.