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Revista chilena de historia natural

versión impresa ISSN 0716-078X

Resumen

VALENZUELA, EDUARDO; LEIVA, SERGIO  y  GODOY, ROBERTO. Seasonal variation and enzymatic potential of microfungi associated with the decomposition of Nothofagus pumilio leaf litter. Rev. chil. hist. nat. [online]. 2001, vol.74, n.4, pp. 737-749. ISSN 0716-078X.  http://dx.doi.org/10.4067/S0716-078X2001000400001.

The seasonal variation and enzymatic potential of microfungi isolated from senescent leaves and leaf litter of Nothofagus pumilio was studied. The study was performed in a N. pumilio forest located in a microcatchment of the Antillanca Valley, Puyehue National Park (40º 47' S, 72° 12' W, 1,120 m of altitude). Senescent leaves recently collected from N. pumilio trees were enclosed in litter bags and subjected to natural degradation on the forest leaf litter during 1 year (March 1997-March 1998), with seasonal sampling. The isolation of microfungi was performed through the dilution plate technique using malt extract agar (2 %) as the isolation medium. The enzymatic degradation potential of microfungi was determined in vitro by testing amylase, cellulase, pectinase, protease, laccase, extracellular oxidase, peroxidase, cytochrome oxidase, phosphatase, esterase and tyrosinase activities. The mycoflora of the senescent leaves was dominated by Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Phialophora group hoffmanni and Rhodotorula aurantiaca. The most abundant species found in the leaf litter were Hormonema prunorum, Mortierella ramannniana var. angulispora, Penicillium para-herquei and Trichoderma polysporum. The Moniliales and sterile micelia exhibited the highest enzymatic degradation potential, being the lowest Sphaeropsidales and yeasts. Individually, the species with the highest degradative potential were Alternaria alternata, Cladosporium cladosporioides, Hormonema prunorum and Phialophora malorum. Cellulase and amylase activities were the most important. Extracellular oxidase and peroxidase were the ligninolitic enzymes with the highest enzymatic potentials

Palabras llave : Nothofagus pumilio; decomposition; leaf litter; microfungi; degradative potential.

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