EFFECTS OF TEMPERATURE AND LIGHT INTENSITY ON THE FORMATION AND RELEASE OF SPORES OF GRATELOUPIA TURUTURU

We discovered for the first time that Grateloupia turuturu filaments, developed from discoid crusts, had the ability to form spores under laboratory condition,which defined as " disc-filamentospore”. We investigated the formation of disc-filamentospores and the effects of various temperatures (6, 12, 16, 20, 24, 30℃) and light intensities (10, 30, 45, 60, 90, 120 μmol/(m².s)) on the release of disc-filamentospores. The results indicated that carpospores that formed and released from cystocarps of female gametophyte of G. turuturu, first developed into discoid crusts. The discoid crusts were induced to form filaments of monolayer cells, which formed massive plurilocular sporangiums and released large amounts of disc-filamentospores.Temperature and light intensity significantly affected the releasing efficiency of disc-filamentospores with the maximum level at 16℃ and 60 μmol/(m²·s). The releasing number of disc-filamentospores reduced when the temperature was lower than 12℃ or higher than 24℃. The light intensity with less than 30 μmol/(m²·s) or more than 90 μmol/(m²·s) significantly inhibited the releasing efficiency of disc-filamentospores. Our results improved the asexual reproduction process of Grateloupia turuturu and provided more abundant theoretical basis for its germplasm preservation, artificial breeding and aquaculture. Finally, we suggest a plausible solution to investigate the origin and evolution of Grateloupia turuturu.