Culture study on the hybrid by interspecific crossing between Porphyra pseudolinearis and P. dentata (Bangiales, Rhodophyta), two dioecious species in culture

Abstract

Physiological studies on the hybrid by crossing between two dioecious species, Porphyra pseudolinearis and P. den- tata from Korea were conducted at constant temperatures (5, 10, 15, 20, and 25°C), at photon flux densities (10, 20, 40, and 80 µmol m-2 s-1 observed at 20 and 40 µmol m-2 ) under photoperiods (14 L : 10 D and 10 L : 14 D). In the hybrid, higher growth of conchocelis was s-1 under 14 L : 10 D. Conchosporangial branches were produced under 10-80 µmol m-2 s-1 at only 25°C, and were abundant when the conchocelis was cultured under 10 L : 14 D. Foliose thalli of the hybrid grew well at the conditions of 10-20°C, 10 L : 14 D and 15-20°C, 14 L : 10 D. The foliose thalli grew very slowly at 5°C and 30°C, respectively. No archeospores were observed at any culture conditions. Spermatangial and zygotosporangial sori were formed at the marginal portion of mature thallus. Zygotospores from the hybrid were released at 10-20°C under both photoperiods, and gave rise to form conchocelis filament. Monoecious thalli were observed at 10°C under 14 L : 10 D. Neither monospores nor protothalli were produced from the conchocelis in culture.