CONICET | Buscador de Institutos y Recursos Humanos

Undaria pinnatifida (Harvey) Suringar is an edible Brown kelp cultured off the coasts of Korea, China and Japan. While its proliferation is encouraged and indeed nurtured in several places, in other is seen as a terrible nuisance species, a threat to the health and therefore the focus of containment and eradication efforts. U. pinnatifida is widely distributed in Europe, Asia, Mexico, Australia and New Zealand. In December 1992, was detected for the first time in Argentina, in Puerto Madryn. Since then, ecological and morphological studies have been done, but the present is the first study on epi-endophytic algae on thalli from Argentinian coasts. Collections of Laminariocolax aecidioides growing in sporophytes of U. pinnatifida were made during June and December 2004. They were macroscopically observed as dark zones formed by confluent points, 1-2 mm in diameter that covered U. pinnatifida fronds partially. In nature, L. aecidiodes presented filamentous vegetative thalli, uniseriate and branched. L. aecidioides is described from laboratory cultures. Small fragments of the cortical layer of U. pinnatifida were excided and cultured in PES medium. Cultures were maintained at 21 ±1°C, with an illumination regime of 12:12 h LD and a photon flux density of 15 µmol m-2s-1. Isolates developed into filamentous-branched microscopic thalli. They were sporophytes that reproduced by both unispores and plurispores from unilocular and plurilocular sporangia. L. aecidiodes presented a cycle life constituted by two microscopic generations and isogamy. The sporophytic diplod phase presented 16 chromosomes and the gametophytic haploid phase 8 chromosomes.