Algae. 1998; 13(2): 207-211.
Life History and Growth of the Epiphytic Thallus of Porphyra lacerata (Bangiales, Rhodophyta) in Culture
Masahiro Notoya, Kazuhiro Nagaura
Laboratory of Applied Phycology, Tokyo University of Fisheries
This is the first on small epiphytic foliose thalli of Porphyra lacerata from Banda, Chiba Prefecture, Japan. Matured foliose thalli from the field were 17 mm × 24 mm in maximum length and width, and occurred as epiphytes on Myelophycus simplex or Ishige okamurae. They were clearly smaller than those of epilithic thalli from Enoshima, Kanagawa Prefecture. Zygotospores and conchospores were cultured to observe their life history at various temperatures(5,10,15,20, 25 and 30℃) and two photoperiods (14L:10D and 10L:14D) under a photon flux density of 40 μmol m super(-2) s super(-1). Typical biphasic cycle of the P. lacerata-type was observed. The foliose thalli produced archeospores at 10-25℃ under both photoperiods, and produced zygotospores at 10-15℃ under short photoperiod and at 10-20℃ under long photoperiod. The foliose thalli and the conchocelis filaments could not survive at 30℃. The maximum size of foliose thallus, 22 mm × 25 mm(length × width) was observed at 10℃ under a 10L:14D after 15 weeks in culture. The size and shape of thalli in culture were similar to the field materials, epiphytic on Myeolphycus simplex. Hus' formula in cultured thalli, was 64(a/4,b/4,c/4) or 32(a/4,b/2,c/4) in spermatangium and 8(a/2,b/2,c/2) or 4(a/2,b/1,c/2) in zygotosporangium, respectively. Zygotospore germlings grew to conchocelis filanments. It grew quickly at 15℃ under long photoperiod. Conchosporangial branches were produced at 25℃ under both photoperiods. Conchocelis produced neither monospores nor protothalli.
Keywords : Bangiales, epiphytic thallus, life history, Porphyra lacerata, Rhodophyta