Myxomycetes ocorrentes em microhabitates especiais em Ãreas de Floresta AtlÃntica no Nordeste do Brasil: espÃcies florÃcolas / Floricolous myxomycete biota of four Atlantic Forest conservation units in the states of Pernambuco and ParaÃba; Northeast Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Studies on myxomycetes are focused mainly on lignicolous; foliicolous; and corticicolous species; and many types of substrates and environments are still unexplored. Recent research carried out in moist forests suggests high diversity of species in inflorescences of large tropical herbs. This study aimed to increase the knowledge about the Neotropical distribution of floricolous myxomycete species by verifying the occurrence of this ecological group in different altitudes (30 m - 700 m) of four Atlantic Forest conservation units located in the states of Pernambuco and ParaÃba. The plants studied belonged to the genus Heliconia (Heliconiaceae; Zingiberales). Their inflorescences are large and have a long flowering period; their flowers have relatively large and slightly coarse tepals; protected by hard bracts that create microenvironments which conserve debris and humidity; and extrafloral nectaries favor the development of yeasts and bacteria; providing food for the plasmodia. The presence of myxomycetes was studied in each area in dead parts of inflorescences that were still bound to the mother plant; as well as by cultivation in 368 moist-chambers. A list of 33 floricolous species is presented â based on a revision of world literature â as well as a commented list of the 10 species recorded for the conservation units; these species belonged to Didymiaceae (Didymium; 3 spp.); Physaraceae (Physarum; 5 spp.); Trichiaceae (Arcyria; 1 sp.); and Stemonitaceae (Comatricha;1 sp.). The floricolous speciesâ preference for substrates with a basic pH was confirmed. P. compressum was common to all myxomycete biotas studied; which demonstrated that it is one of the characteristic species of this ecological group. For the first time D. anellus; D. minus; and P. sulphureum are referred as sensu stricto floricolous species; in the world. The two conservation units higher than 400 m had similar myxomycete biotas and were significantly different from those below 100 m. P. compressum and A. cinerea are the most characteristic species of the floricolous myxomycetes groups occurring in the conservation units analyzed. This study confirms that there is a stable; specific group of myxomycetes that occur in the decaying floral parts of Heliconia sp. inflorescences that are still bound to the mother-plant

ASSUNTO(S)

floresta atlÃntica heliconia myxomycete myxomycetes microbiologia floricolous atlantic forest heliconia florÃcola

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