• ALGAE
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• v.39 no.1
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• pp.31-41
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• 2024

Acadian marine plant extract powder (AMPEP) and Kelpak are commercial biostimulants derived from brown algae Ascophyllum nodosum. This study was to determine if AMPEP and Kelpak can induce thermal resistance in Pyropia yezoensis. P. yezoensis blades were exposed to different concentrations (control: 0, low: 0.001, high: 1 ppm) of AMPEP and Kelpak at 10℃ for 6 and 7 days, respectively. Those blades were then cultivated in von Stosch enriched seawater medium at different temperatures (10, 15, 20, and 25℃) with 12 : 12 L : D photoperiod and 100 µmol m^-2 s^-1 of photosynthetically active radiation for additional 15 days. Results showed that P. yezoensisreproduced archeospores at 20 and 25℃ at all biostimulant conditions within 15 days. At lower temperatures (10 and 15℃), only AMPEP-treated P. yezoensis reproduced archeospores. P. yezoensis exposed to 1 ppm Kelpak exhibited higher phycoerythrin and phycocyanin contents than control and 0.001 ppm conditions at 15℃. AMPEP-treated conditions showed higher phycoerythrin and phycocyanin contents than control at 10℃. These results suggest that AMPEP and Kelpak may not enhance the thermal resistance of P. yezoensis. However, AMPEP stimulated archeospores release at lower temperatures. The treatment of AMPEP and Kelpak also increased the pigment contents in P. yezoensis. These results suggest that the use of seaweed-derived biostimulants can provide some economic benefits in P. yezoensis aquaculture. The enhancement of archeospores formation by AMPEP at lower temperature may also increase the productivity since Pyropia farming relies on the accumulation of secondary seedings via asexual reproduction.

• ALGAE
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• v.21 no.2
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• pp.193-208
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• 2006

Porphyra pulchella sp. nov. Ackland, West, Scott and Zuccarello was obtained at Mimosa Rock National Park, New South Wales; Westgate Bridge, Victoria, Australia; and Waihau Bay, North Island, New Zealand. It occurs mainly in mangrove habitats and is very small (± 1 mm) in field collections. In laboratory culture at 21 ± 2°C tiny blades (0.5-3.0 mm) reproduced exclusively by archeospores liberated from vegetative cells of the upper sector of the blades. The archeospores displayed amoeboid and gliding motility once discharged. At 14 ± 2°C the blades grew to 25 mm and produced longitudinal spermatangial streaks mixed with ‘phyllosporangial’ streaks. The discharged ‘phyllospores’ showed amoeboid motility and germinated forming asexual blades. A conchocelis phase with typical bangiophycidean pit connections was observed in blade cultures after 8-10 weeks at 14 ± 2°C. Conchocelis filaments produced conchosporangia and these released amoeboid conchospores that developed into archeosporangiate blades. Molecular data indicate that all 3 isolates are genetically identical.

• ALGAE
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• v.26 no.1
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• pp.79-86
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• 2011

Physiological studies on the hybrid by crossing between two dioecious species, Porphyra pseudolinearis and P. dentata from Korea were conducted at constant temperatures (5, 10, 15, 20, and $25^{\circ}C$), at photon flux densities (10, 20, 40, and $80\;{\mu}mol\;m^{-2}s^{-1}$) under photoperiods (14 L : 10 D and 10 L : 14 D). In the hybrid, higher growth of conchocelis was observed at 20 and $40\;{\mu}mol\;m^{-2}s^{-1}$ under 14 L : 10 D. Conchosporangial branches were produced under $10-80\;{\mu}mol\;m^{-2}s^{-1}$ at only $25^{\circ}C$, and were abundant when the conchocelis was cultured under 10 L : 14 D. Foliose thalli of the hybrid grew well at the conditions of $10-20^{\circ}C$, 10 L : 14 D and $15-20^{\circ}C$, 14 L : 10 D. The foliose thalli grew very slowly at $5^{\circ}C$ and $30^{\circ}C$, 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 $10-2^{\circ}C$ under both photoperiods, and gave rise to form conchocelis filament. Monoecious thalli were observed at $10^{\circ}C$ under 14 L : 10 D. Neither monospores nor protothalli were produced from the conchocelis in culture.

• Journal of Aquaculture
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• v.13 no.4
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• pp.353-357
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• 2000

Porphyra pseudolinearis and P. dentata from Korea were crossed and the hybrid was cultured at different temperatures (5, 10, 15, 20 or $25^{\circ}C$), photon flux densities (10, 20, 40 or 80${\mu}$mol m$^{-2}$s$^{-1}$) under photoperiods (14L:10D and 10L:14D). In the hybrids, the conchocelis grew faster at 2$0^{\circ}C$ and 40$\mu$mol m$^{-2}$ s$^{-1}$ at $25^{\circ}C$ only, and were abundant, when cultured under 10L:14D. Foliose thalli of the hybrid grew rapidly at conditions of 10-2$0^{\circ}C$, 10L:14D and 15-2$0^{\circ}C$, 14L:10D but slowly at 5 and 2$0^{\circ}C$. No archeospores were observed any tested culture condition. Spermatangial and zygotosporangial sori were formed at the marginal portion o mature thallus. Zygotospores from the hybrid were released at 10-2$0^{\circ}C$ under both photoperiods, and gave rise to form conchocelis filament. Monoecious thalli were observed at 1$0^{\circ}C$ under 14L:10D. Neither monospores nor protothalli were produced from the conchocelis in culture.

• Journal of Aquaculture
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• v.13 no.4
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• pp.295-301
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• 2000

Mature foliose thalli of P. suborbiculata f. Iatifalia were collected at Chindo, Chonnam Prefecture on 24 February 1996. Growth and reproduction were observed at selected temperatures (5~30tt photon flux densities (10-80 ${\mu}$mol m$^{-2}$s$^{-1}$) and photoperiods (14L:I00, 10L:140). The thalli grew fastest at 15 t under both photoperiods and produced archeospores at 10-$25^{\circ}C$ under both photoperiods, but zygotospores at 10-15$^{\circ}C$ under 10L:140 and at only 15$^{\circ}C$: under 14L:I00. Size and shape of the thalli at 1$0^{\circ}C$: under short photoperiod were similar to the field materials. The optimum temperature and photoperiod for growth of the conchocelis colony were 20-$25^{\circ}C$: under both photoperiods. The foliose thalli and the conchocelis filaments could not survive at 30 t. Conchosporangial branches were produced at 15-$25^{\circ}C$ under 14L:100 and 10L:140.