Population studies in Gracilariopsis tenuifrons (Gracilariales, Rhodophyta): physiological and molecular approaches

Abstract

Intraspecific diversity includes phenotypic and genotypic expressions in individuals of a species, resulting from acclimation and adaptation processes. Gracilariopsis tenuifrons (C.J. Bird and E.C. Oliveira) Fredericq & Hommersand is an agarophyte widely distributed on the Brazilian coast. Studies that aim to know their diversity, intrapopulational or among the different populations distributed along the coast, should make possible the characterization and selection of strains. The present work has the following objectives: i) evaluate the physiological aspects of non-fertilized female gametophytes of populations from Rio Grande do Norte State, Bahia State and São Paulo State, cultivated in laboratory conditions under different temperatures (20-32°C); ii) evaluate the diversity of three populations (the same ones mentioned in the previous objective), accessing genetic markers, cox 1 and cox 2-3; and iii) evaluate the physiological aspects of unfertilized female gametophytes, cystocarpic plants, male gametophytes and tetrasporophytes from the same population cultivated under laboratory conditions. To achieve the objectives i and iii the following parameters will be analyzed: growth rates (weekly fresh biomass), pigment content and photosynthesis. The accomplishment of these studies should allow the physiological characterization of the selected populations and will be important for the recognition of putative ecotypes. In addition, it may contribute to the choice of the best reproductive stage for strain selection aimed at mariculture of G. tenuifrons. (AU)