Growth and reproductive responses of the conchocelis phase of Pyropia hollenbergii (Bangiales, Rhodophyta) to light and temperature

Effects of light and temperature on conchocelis growth of Pyropia hollenbergii were evaluated with the hypothesis that conchocelis phase is most adapted to environmental extremes as compared to the gametophyte phase. Growth rates were measured weekly over a 3-month experimental period. Our results have shown that the best growth rate was 6.4 to 7.5 % area day−1 at 25 °C, at photon fluence rates between 50 and 150 μmol photons m−2 s−1 and at a photoperiod of 15:9 h L: D. The upper temperature tolerance limit of Py. hollenbergii was at 33 °C at a photon fluence rate between 10 and 50 μmol photons m−2 s−1 and photoperiods of 9:15 and 12:12 h L:D. At a temperature of 5 °C, growth was inhibited (