• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.704-711
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• 2015

We examined the effects of temperature and light intensity on gametophyte growth of Ecklonia cava Kjellman. The growth of female and male gametophytes was investigated before maturation. Gametophytes prepared from Munseom, Jeju, Korea in October 2014 were separated by sex and maintained under the following conditions: 15℃, 20 μmol·m^-2·s^-1, and a 12-h/12-h light/dark cycle. The experiments were conducted at five temperatures (10, 15, 20, 25, and 30℃) and three light intensities (5, 20, and 40 μmol·m^-2·s^-1). Daily growth rates were estimated by the increase in filamentous frond area. The optimal growth conditions for female gametophytes were 20℃ and 40 μmol·m^-2·s^-1; the optimal conditions for male gametophytes were 15℃ and 20 μmol·m^-2·s^-1. The relative growth rates (RGR) of female and male gametophytes decreased at 25℃ and 30℃, respectively. At 30℃, RGRs of gametophytes decreased by approximately 1.0% day^-1. In addition, RGRs of male gametophytes were higher than those of female gametophytes. These results indicate that female gametophytes were more sensitive to temperature and light intensity than male gametophytes. Moreover, these results suggest that E. cava growth rates could decrease as a result of global warming.

• Ocean and Polar Research
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• v.42 no.2
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• pp.133-139
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• 2020

The aim of this study is to examine the physiological characteristics of an agarophyte Agarophyton vermiculophyllum (Ohmi) Gurgel, J.N. Norris et Fredericq in the early life stage of tetrasporophytes (2n) and gametophytes (n) to select appropriate seedlings for mariculture. Growth experiments were carried out at the combinations of four temperatures (20, 25, 30, and 35℃) and three light intensity levels (20, 60, and 100 µmol photons m^-2 s^-1) in the two ontogenetic stages: discoid holdfasts and erect sporelings. Holdfast areas and sporeling lengths of tetrasporophytes and gametophytes were estimated after 14 days in culture. Relative growth rates (RGRs) for holdfast areas were 7.08-28.38% day^-1 for tetrasporophytes and 11.58-23.67% day^-1 for gametophytes. At 35℃, holdfasts of tetrasporophytes survived with RGRs of 7.08-23.28% day^-1 but those of gametophytes died. Maximal holdfast growth of tetrasporophytes occurred at 30℃ and 100 µmol photons m^-2 s^-1, which were different from gametophytes (25℃ and 100 µmol photons m^-2 s^-1). RGRs of tetrasporophytic sporelings were 2.93-11.11% day-1 and were between 0.78-10.82% day-1 for gametophytes. Maximal growth of A. vermiculophyllum sporelings occurred at 25℃ and 60 µmol photons m^-2 s^-1 for tetrasporophytes, and at 20℃ and 100 µmol photons m^-2 s^-1 for gametophytes. In conclusion, the present results indicate that carpospores could be used as resources of spore-seedling methods having genetic diversity for mass field cultivation because tetrasporophytes showed higher-temperature tolerance and faster-growing ability than gametophytes of A. vermiculophyllum in the discoid holdfast and sporeling stages.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.2
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• pp.219-221
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• 2017

In 2015, white cottony tufts were observed on gametophytes of the kelp Saccharina japonica. Wet mount and histopathology examination revealed numerous fungal hyphae and mycelium around the gametophytes. The gametophytes surrounded by fungal hyphae were generally round and empty. A specific 610-bp fragment of the internal transcribed spacer (ITS)-5.8S rDNA-ITS gene of fungi was amplified by polymerase chain reaction and the nucleotide sequence showed 100% identity with those of Acremonium sclerotigenum, Acremonium sp. and Ascomycota sp. When fungus-infected gametophytes were mixed with healthy gametophytes, a high transmission rate (100%) resulted. This is the first report of mycosis of gametophytes in Korea.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.2
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• pp.115-122
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• 2020

Eisenia bicyclis, a perennial macroalga is a primary producer of in the ocean, It has been identified as a key species that plays a vital role in maintaining the ecosystem stability. Also, it is an important target in marine afforestation projects and useful marine organisms. In addition, E. bicyclis is used as a health food for humans. This study investigated the effect of water temperature, light (photon irradiance), and duration of light (photoperiod) on the growth of gametophytes and young sporophytes of E. bicyclis. The germination and growth of the zoospores of E. bicyclis were examined at five temperatures (5℃, 10℃, 15℃, 20℃ and 25℃), four intensities of photon irradiance (10, 20, 40, and 80 μmol m-2s-1), and photoperiods (14:10 and 10:14 light/dark cycles). The zoospores released from mature plant germinated into the gametophytes under all experimental conditions. The gametophytes were able to grow at water temperature 5℃-25℃ and mature at 10℃-20℃. The optimal range of water temperature for the maturation of the gametophyte was 15℃-20℃. At 25℃, E. bicyclis gametophytes grew rapidly but did not mature. The optimal culture conditions for the growth of young sporophytes grew slowly in low temperature and photon irradiances.

• Ocean and Polar Research
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• v.37 no.3
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• pp.201-209
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• 2015

To examine the effects of increased $CO_2$ concentration and seawater temperature on the photosynthesis and growth of forest forming Ecklonia cava (Laminariales, Phaeophyta), sporophytic discs and gametophytes were cultured under three $pCO_2$ concentrations (380, 750, 1000 ppm), four temperatures (5, 10, 15, $20^{\circ}C$ for sporophytes; 10, 15, 20, $25^{\circ}C$ for gametophytes), and two irradiance levels (40, $80{\mu}mol$ photons $m^{-2}s^{-1}$) for 5 days. Photosynthetic parameter values ($ETR_{max}$, $E_k$, and ${\alpha}$) were generally higher as sporophytic discs were grown under low temperature and increased $CO_2$ concentration at 750 ppm. However, photosynthesis of Ecklonia sporophytes was severely inhibited under a combination of high temperature ($20^{\circ}C$) and 1000 ppm $CO_2$ concentration at the two photon irradiance levels. The growth of gametophytes was maximal at the combination of 380 ppm (present seawater $CO_2$ concentration) and $25^{\circ}C$. Minimal growth of gametophytes occurred at enriched $pCO_2$ concentration levels (750, 1000 ppm) and high temperature of $25^{\circ}C$. The present results imply that climate change which is increasing seawater temperature and $pCO_2$ concentration might diminish Ecklonia cava kelp beds because of a reduction in recruitments caused by the growth inhibition of gametophytes at high $pCO_2$ concentration. In addition, the effects of increased temperature and $pCO_2$ concentration were different between generations - revealing an enhancement in the photosynthesis of sporophytes and a reduction in the growth of gametophytes.

• ALGAE
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• v.37 no.2
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• pp.163-174
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• 2022

Light-emitting-diodes (LEDs) are a lighting source useful for the precise evaluation of light quality effect on biological systems. Despite the importance of light spectra on the regeneration of land plant protoplasts ("naked cells"), this factor has not been tested yet on protoplasts from multicellular algae. This study reports on the effects of pure primary colors (red, blue, and green), dichromatic (red plus blue, RB, 1 : 2) and white LEDs on protoplast regeneration from male and female Undaria pinnatifida gametophytes. We also evaluated the effect of different light spectra on pigment composition (chlorophyll a, chlorophyll c, and fucoxanthine), and the light intensities under the best condition on the regeneration process. In the early stages, blue or RB LEDs increased the percentage of dividing female protoplasts, whereas red, blue, and RB LEDs enhanced that of dividing male protoplasts. In the later stages, RB LEDs showed a positive effect only on the percentage of multiple rhizoid-like protrusions (male gametophyte). They also increased the final area of both regenerated gametophytes. The LEDs did not affect pigment composition in female gametophytes. In male gametophytes, in contrast, they reduced chlorophyll c, while blue, RB, and green LEDs decreased fucoxanthin. Under RB LEDs, the optimal light intensity was 80 µmol photons m^-2 s^-1 for female gametophytes and 40 to 60 µmol photons m^-2 s^-1 for male gametophytes. Our results suggest that dichromatic LED illumination (red-blue) improves regeneration of U. pinnatifida gametophyte-isolated protoplasts. Thus, dichromatic LEDs might a suitable light source for enhancing protoplast regeneration in brown seaweeds.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.231-238
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• 2010

The Induction of regeneration and maturation in the free-living gametophytes of Ecklonia stolonifera Okamura was studied at four temperatures (5, 10, 15, and $20^{\circ}C$), four levels of irradiance (5, 10, 20, and 40 ${\mu}mol\;m^{-2}s^{-1}$) and three photoperiods (14:10, 12:12, and 10:14 h L:D). Female gametophyte fragments were maintained in active regeneration without reaching sexual maturity under $5{\sim}10^{\circ}C$, 10 ${\mu}mol\;m^{-2}s^{-1}$, 10:14 h (L:D), whereas the conditions for male gametophytes were slightly different at $20^{\circ}C$, 40 ${\mu}mol\;m^{-2}s^{-1}$, 10:14 h (L:D). The sexual maturation of female and male gametophytes was facilitated at $15^{\circ}C$, 20 ${\mu}mol\;m^{-2}s^{-1}$, 14:10 h (L:D). These results provide basic information for controlling the regeneration and maturation of the free-living gametophytes for artificial seed production of E. stolonifera.

• FLOWER RESEARCH JOURNAL
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• v.18 no.1
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• pp.9-14
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• 2010

This study was conducted to examine the effects of IAA and kinetin on induction of gemmae and gametophytes in Hypnum plumaeforme moss during tissue culture. Explants were obtained from sterilized gametophyte tips cultured on solid basal medium containing Knop's major salts and Nitsch and Nitsch's trace elements. After culture, inoculated gametophyte tip produced protonema firstly, changed to new gametophytes after four weeks. Aseptic gametophytes were chopped and inoculated on the same media containing 0.01, 0.1, 1 and $10{\mu}M$ of IAA and kinetin. As a result, secondary protonemata as well as protonemal gemmae were formed from gametophytes. But protonemal gemmae formation was varied according to the concentration of IAA and kinetin. Lower concentration of IAA and kinetin promoted gemma formation and bud induction. Especially, $0.01{\mu}M$ of kinetin showed the highest frequency of bud and gemma production. All the materials, obtained from $0.01{\mu}M$ kinetin medium, were subcultured to media supplemented with 0.01, 0.1, 1 and $10{\mu}M$ of IAA and kinetin again to induce gametophytes. After subculture, protonema and calli were developed from secondary protonema, and induced gametophytes finally. IAA regulated induction and growth of gametophytes, and kinetin influenced gemma formation and gametophyte induction also. All aspects of development of this moss species were governed by the external growth regulators.

• Proceedings of the Botanical Society of Korea Conference
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• 1996.06a
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• pp.10-17
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• 1996

Fern gametophytes are a good model system to study plant morphogenesis, because of their simple organization and various photocontrolled responses. We studied fern photomorphogenesis including chloroplast photoorientation using Adiantum gametophytes to analyze signal transduction pathways of plant photomorphogenesis. Chloroplast photoorientation will be shown in detail and molecular structure of fern phytochromes and blue light absorbing pigments will also be discussed.

• Korean Journal of Plant Taxonomy
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• v.50 no.4
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• pp.403-412
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• 2020

Colonies of three independent gametophytes (one that is filamentous and two that are ribbon-like) without sporophytes occur in Gyeonggi-do, Gangwon-do, Gyeongsang-do, and Jeju-do, Korea. They have a moss-like appearance at first sight, with tiny plantlets and gemmae, and grow in cool, shaded, relatively deep dint places of large rocks, such as the small caves in high mountains, close to valleys. The gametophytes were identified based on morphological and molecular data by chloroplast DNA (cpDNA) sequence data (rbcL, rps4 gene and rps4-trnS intergenic spacer). Here, rbcL, rps4 gene and rps4-trnS intergenic spacer data of one independent gametophyte distributed in Korea have the same morphology, DNA sequence and monophyletic group as Crepidomanes intricatum from the eastern United States. They also share the same cpDNA data with Crepidomanes schmidtianum recently reported from Korea. The other independent gametophyte should be Hymenophyllum wrightii based on cpDNA data. The last one was presumed to be Pleurosoriopsis makinoi based on molecular data. The taxonomic status was confirmed to be the forma of Hymenophyllum wrightii through a revision of Hymenophyllum wrightii f. serratum based on molecular data.