Culture Studies of Four Species of Porphyra(Rhodophyta) from Japan.

Abstract

Porphyra lacerata, P. tenuipedalis, P. suborbiculata, and P. dentata were cultured under various photon flux densities (10-80 μmol m-2s-1), temperatures (10-25°C), and photoperiods (14L: 10D, 10L: 14D) to observe their life cycles. P. lacerata and P. suboribculata both had a similar type of life cycle with a monoecious, foliose thallus producing monospores at an early stage at 10-25°C and a conchocelis-phase which produced only conchosporangial branches. P. dentata had a dioecious, foliose thallus which produced no monospores. P. tenuipedalis had a monoecious, foliose thallus which produced no conchosporangial branches. In these four species, the optimum temperature and photoperiod for growth of the conchocelis- and foliose-phases were similar; 20-25°C under 14L: 10D for the conchocelis-phase and 15-20°C under 1OL: 14D for foliose thalli.