Laboratory Culture of Porphyra lacerata (Rhodophyceae, Bangiales)

The life history of red alga Porphyra lacerata Miura collected from Mogi, Nagasaki Prefecture, was studied in laboratory culture. The culture studies were initiated with using the free-living conchocelis thalli. Fragments of conchocelis thalli were inoculated to oyster shells in culture vessels. Regenerated branchelets penetrated into shells and developed to new conchocelis thalli. The growth morphology and growth rate of shell-living conchocelis thalli was similar to those of P. yezoensis. The optimum temperature for the induction of conchosporangia was ranged from 25-27.5℃ in P. lacerata which was higher than in P. yezoensis (20-25℃). The liberated conchospores germinated into leafy thalli which grew to about 1 cm in length and matured after one month in culture. Matured thalli were monoecious and released both carpospores and monospores in lower temperatures (15-20℃). The matured thalli attained to about 4-9 cm in length after three months in culture. The thickness of the vegetative thalli was comparatively thinner than the other Porphyra species. The chromosome number of P. lacerata was counted to be two in vegetative and antheridial cells and four in carpospore germlings and conchosporangia