Antioxidants in Pinus Pinaster and mycorrhizal fungi during the early steps of symbiosis
Artigo de Conferência
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resumo
Ectomycorrhizal symbiosis between fungi and the roots of some plants could have
important effects in t he levels of antioxidants of both partners [1,2]. In the present work,
the effects of eo-culture period (6, 24 and 72 h) in the antioxidant properties and
antioxidants production duri ng early steps of in vitro mycorrhization (Pinus pinaster -
Pisolithus arhizus and Pinus pinaster - Paxillus involutus) were evaluated. The studied
parameters were determined in each culture element (root, mycelium and medium) in
order to understand the response of each part ner to the symbiot ic association. The
antioxidant properties were determined by assays evaluating free radicals scavenging
activi ty, reducing power, ~-ca rotene bleaching inhibition and lipid peroxidation inhibition
in animal brain homogenates. The concent rations in phenolics, tocopherols and suga rs
were obtained by Folin Ciocalteus assay, HPLC-fluorescence and HPLC-RI, respectively. P.
arhizus proved to be more compatible with P. pinaster than P. involutus, since the
antioxidant activity in the latter species increased from 48 to 72 h, while P. arhizus
antioxidant properties decreased at the same period (less oxidative stress). Despite P.
involutus proved to be less suitable to be included in forestation programs using
mycorrhization processes, it revealed a higher potential for bioactive compounds
production in the early steps of symbiosis. A maximal phenolics content was obtained
after the first 6 h and, considering bioactive compounds production purposes, the eoculture
should be stopped at t hat time. Tocopherols (except y-tocopherol) contents
showed high similarities among culture medium and mycelia. This tendency could not be
observed regarding sugars contents, which might indicate that the differences in t he
chemical responses that characterize each mycorrhization might be related more directly
with sugar (primary metabolites) exchanges.
