Influence of Temperature and Photoperiod on the Life History of porphyra variegata (Kjellman) Kjellman (Bangiales, Rhodophyta) in Culture

Abstract

Life history of Porphyra variegata (Kjellman) Kjellman was completed in culture from Ken-nich, Hokkaido, Japan. Growth and reproduction of both foliose phase and conchocelis phase were observed at various temperatures (5, 10, 15, 20, and 25°C) with a photon flux density of 40µmol·m−2s−1under photoperiods (14L: 10D and 10L: 14D). The optimum growth of the conchocelis filaments occurred at 10°C. Conchocelis filaments produced conchosporangial branches after 6-9 weeks at 5°C and 10°C under a short photoperiod of 10L: 14D. Conchospores were released in great nombers from the conchosporangia at 10°C under short photoperiods of 10L: 14D and 8L: 16D. Conchospore germlings developed into the foliose thallus and reached to 1-5 cm in length after 3-5 months at 5°C and 10°C under long and short photoperiods. The foliose thallus produced only sexual spores as zygoto-spores. Reproductive organs were not produced from small globular thalli at 15°C. Asexual spores were not produced from the foliose thallus. © 1999, The Japanese Society of Fisheries Science. All rights reserved.