Life cycle of Punctaria latifolia (Chordariaceae, Phaeophyceae) from coast Buenos Aires Province, South America

GAUNA, M.C.; PARODI, E.R

ALGOLOGICAL STUDIES

E. Schweizerbart?sche Verlagsbuchhandlung

Lugar: Stuttgart, Germany; Año: 2010 p. 55 - 66

0342-1120

The objective of this study was to describe the morphology of Punctaria latifolia individuals from the natural environment, their life cycle under culture conditions and the kariology of different phases. The life cycle of Punctaria latifolia was studied under culture conditions (140 µmol m-2 s-1; 12 h/12h; 21 ± 1 °C). Fertile sporophytes were collected in the intertidal zone of Bahía San Blas (Buenos Aires, Argentina, South America), in August and December 2003. These macroscopic laminar plants were found adhered to the rocky substrate and on Spartina alterniflora plants. Sporophytes from natural environment presented both plurilocular and unilocular sporangia, which released plurispores and unispores, respectively. The asexual reproduction was evidenced by the germination of unispores by formation of a single - pole germination that originated microscopic filamentous gametophytes. Terminal and intercalar gametangia released isogametes. Zygotes reconstituted the macroscopic phase. Chromosome counts gave 16 and 8 for sporophytic - and gametophytic- phases, respectively. This species presented haplodiplobiontic heteromorphic life cycle as well as a direct type, when plurispores produced plethysmothalli.