‘Seed’ production of Porphyra spp. by tissue culture

Differentiation of archeospores was observed from excised tissue of young thalli of various monoecious Porphyra species ( P. tenera, P. yezoensis, P. suborbiculata, P. okamurae) after 4–8 days in culture at temperatures of 20 and 25 °C. Excised tissue from adult thalli did not differentiate into archeospores, but rather regenerated directly into blades and rhizoids of foliose thalli. Tissues from young thalli of two dioecious Porphyra species ( P. dentata and P. pseudolinearis) also regenerated into blades and rhizoids after manipulation of the culture conditions. In addition, 1–2 celled tissue pieces of both monoecious and dioecious species were also seen to develop directly into blades. Polarity of regeneration of blades and rhizoids was observed in these species. These results suggest that ‘seed’ can be obtained through tissue culture instead of using conventional conchocelis culture for commercial nori aquaculture in Japan.