Growth and development of Porphyra marcosii (Bangiales, Rhodophyta) under different temperatures and photoperiod
2011
Monotilla, W.D. | Notoya, M.
This is the first report on the growth and development of Porphyra marcosii Cordero (Bangides, Rhodophyta) a tropical Porphyra species from the Coast of Burgos, Ilocos Norte, Philippines, Blade and conchocelis cultures were incubated at different temperatures (5, 10, 15, 20, 25 and 30 deg C) and two photoperiod regimes (14L:10D or LD) and (10L:14D or SD) at a photon flux density (PFD) of 60-80 umol/sq m/s. Conchocelis filaments grew at 15-30 deg C under both photoperiods. Conchosporangial formation and maturation was restricted to 30 deg C under SD conditions. Induction of conchospore release was at 20-30 deg C with optimum conchospore production under SD. Thallus blades grow at 15-30 deg C under both photoperiods. Blade archeospores were copiously released at 20-30 deg C and developed into new blade germlings. Male and female gametes were produced at 20-25 deg C and germinated after fertilization into free-living conchocelis under both photoperiods. 'Phyllospores' from the blades were produced at 30 deg C and directly developed into conchocelis forming a conchocelis subcycle. The conchocelis also produced conchosporangia producing conchospores that grew into 1) normal blade germlings, and 2) a compact callus-like free-living conchosporangia'. Subsequently, these released conchospores that germinated into another generation of blade germlings. This tropical Porphyra species exhibited a typical bi-phasic P. lacerata-type life history with considerable variations not commonly observed in most Porphyra species. The reproductive variations were considered adaptation to environmental pressures prevailing in its local habitat.
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