ABUNDANCE AND DIVERSITY OF ECTOMYCORRHIZAS IN NATIVE AND NURSERY CULTIVATED NOTHOFAGUS NERVOSA SPECIMENS

FERNÁNDEZ NATALIA; FONTENLA SONIA; GALLO LEONARDO; MARCHELLI PAULA

Belo Horizonte, Brasil

Congreso; 6th International Conference on Mycorrhizas (ICOM6); 2009

The establishment, survival and growth of different tree species depend on ectomycorrhizas (ECM). Nothofagus nervosa is a Patagonian species that was overexploited and its populations were reduced, determining the implementation of domestication programs. ECM can be important for the successful establishment of outplanted seedlings, so they must be considered in these programs. The aim of the project is to analyze the abundance and diversity of ECM in N. Nervosaand to select strains which would have significant application in domestication processes. The first step was to analyze the percentage of ECM and to compare it among plants of different ages belonging to 4 categories: seedlings, young and old native individuals and young nursery cultivated plants (NCP). Then, ECM were classified in different groups according to its macromorphology, so as to evaluate if the ECM composition changed among plant categories. In autumn 2008, 5 trees of each category were selected from a native forest and from two field trials: one established within a native forest and the other beneath a Pinus plantation. Seedlings were collected with complete root systems and the rest of the plants were sampled by taking 3 soil cores per tree. Roots were sieved from the soil cores and ECM were quantified and classified. Every sample had ECM. In the native forest, more than 90% of the root tips examined per plant were colonized and 22 morphological groups were described, 18 of them were present in the NCP. Young NCP established under the exotic plantation showed a significantly lower colonization (~67%) and only 3 ECM groups were observed. ECM abundance and composition varies between these places, being the percentage values and the biodiversity much higher in the native forest.