IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Ulva lactuca (Ulvophyceae) epiphyted by Myrionema strangulans (Chordariales, Phaeophyceae) from Patagonian coasts
Autor/es:
SINISCALCHI A.G; GAUNA, M.C; CROCE, M.E.; PARODI E.R
Lugar:
Halifax
Reunión:
Congreso; 4th Congress of the International Society for Applied Phycology; 2011
Institución organizadora:
International Society for Applied Phycology
Resumen:
Brown spots produced by the presence of Myrionema strangulans Greville (Chordariales, Phaeophyceae) were observed on Ulva lactuca L. fronds. M. strangulans thalli formed epiphytic discs constituted by vegetative filaments radiating from central to peripheral zone. These epiphytic discs were formed by two strata: monostromatic basal and filamentous erect. From monostromatic stratum reproductive structures and hyaline hairs were generated. These thalli formed both pluriloculars and uniloculars sporangia. M. strangulans was an exclusively epiphytic organism and showed a prevalence of infection of 100% on U. lactuca fronds. Different degrees of infection were established, from the highest to the lower degree of epiphytism. In the cases of strong epiphytism, the host?s cuticle exhibited rupture and perforations, massive depigmentation, and cellular disarray. Under culture conditions zoids from plurilocular and unilocular sporangia germinated. The development of both kinds of cell led to illustrate the life cycle of the epiphytic species. The species exhibited a haplo-diplontic and heteromorphic life cycle, with three different thalli morphologies. Haploid and diploid chromosome numbers were also determinated, being 22 and 44, respectively. The interaction between M. strangulans and U. lactuca has been reported worldwide, but no specific papers were published. Thus, the aim of this paper is to describe this interaction between both organisms, and mainly to describe the life cycle of epiphytic species.