• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.6
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• pp.393-398
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• 2005

Codium fragile is commercially farmed in Korea by natural blooming zygote attachment. Experiments found optimum conditions for artificial seed production and nursery culture of C. fragile by asexual reproduction. Isolated utricles and medullary filaments were regenerated to erect thalli using both indoor and outdoor culture experiments. Under the indoor culture conditions, irradiance was an important factor to control the development of erect thalli. Formation of erect thallus from the isolated medullary filaments in the indoor culture was induced after 30 days under $20^{\circ}C$ and $60{\mu}mol/m^2/sec$. The detachment of isolated utricles and medullary filaments from the substrates of seed strings was reduced by exposure to the air during 2 hrs before the indoor culture of seed strings. The maximum growth and development of erect thalli in the nursery culture was induced at a water depth of 0.5 m. Depending on the substrates of the seed strings the growth of erect thalli was not significantly different (p>0.05).

• ALGAE
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• v.26 no.3
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• pp.221-227
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• 2011

There are three carpet-like Codium species with a broadly expanded thallus reported from Korea and Japan: C. latum Suringar, C. tapetum Y. Lee, and C. tenuifolium Shimada, Tadano and J. Tanaka. During surveys of green algal diversity, we encountered a Codium species with carpet-like thalli from several sites on Jeju Island. To confirm the taxonomic identity of these specimens, we studied the morphological features and obtained rbcL gene sequences. The morphological and sequence data indicated that the carpet-like Codium specimens from Jeju are C. tenuifolium from Japan, but distant from Japanese C. latum. We propose that the carpet-like specimens from Jeju should be renamed C. tenuifolium, instead of C. tapetum or C. latum. C. tenuifolium is characterized by a tenuous, carpet-like and erect thallus with a very short and slightly compressed stipe arising from a discal holdfast, sub-pyriform and clavate utricles with a tumid and swollen apical head, and globular or sub-globular gametangia issued at the basal portion of the utricles.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.3
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• pp.164-171
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• 2005

Codium fragile (Suringar) Hariot, an edible green alga is farmed in Korea by natural blooming zygotes attachment. Experiments were conducted to reveal the conditions for artificial seed production of C. fragile by sexual and asexual reproduction. Growth was compared between zygotes attachment (sexual reproduction) and isolated utricles with medullary filaments (asexual reproduction). Zygotes and isolated utricles with medullary filaments were cultured under different light conditions (10, 20, 40, 60 and $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and temperatures (5, 10, 15, 20 and $25^{\circ}C$) under 16:8LD. Maximum growth of zygote was $261.3{\pm}21.0\;{\mu}m$ under $15^{\circ}C$ and $20\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ after 13 days culture. Maximum regeneration of isolated medullary filament was $8.1{\pm}1.7\;mm$ per one isolated utricle under $20^{\circ}C$ and $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ after 15 days culture. After intermediate culture during two months in the field, morphogenesis occurred in both sexual and asexual reproduction, and growth of young thalli was not significantly different (p>0.05) between the both reproduction methods. Even though seed production of C. fragile is possible in both sexual and asexual reproduction, the mass artificial seed production of asexual reproduction is much more effective than that of sexual reproduction that is too much affected by maturity.

• Journal of Aquaculture
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• v.2 no.1
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• pp.33-41
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• 1989

The present work was carried out to investigate the maturing period and the morphology of utricle Codium fragile collected from April 1984 to March 1985 in the coast of Chumgmu southern of Korea. Ranges of water temperature and salinity during the survey period were $7.5\~27.0^{\circ}C$ and $32.9\~34.5\%_{\circ}$, respectively. The gametangia were produced throughout the year. Mature gametangia were present on plants collected from June to November, whereas most of plants collected from January to May occured as the elongated utricles with both mature and immature gametangia. As for the sexuality, most of plants were dioecious and some monoecious, and there were more male gametophytes rather than female gametophytes. Some plants collected during winter months of December to February were observed as thalli with both brunted and elongated utricles, and male and female gametangia occured together on a single utricle.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.647-654
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• 2015

A prostrate species of Codium (Bryopsidales, Chlorophyta) was collected from Daejin on the eastern coast of Korea. This alga is morphologically characterized by a prostrate, adherent or pulvinate, dark green thallus that is tightly attached to substratum. The utricles are strongly grouped and cylindrical to slightly clavate. Their apex is rounded to capitated, and it frequently has an alveolate ornament. Hair scars are found in the upper portion of the utricle. The gametangia grow on a short pedicel in the upper part of the utricle. In the phylogenetic tree based on molecular data, this alga is placed in the same clade as C. mozambiquense in UPGMA analysis, and nests in a sister clade of C. lucasii subsp. capense and C. mozambiquense in ML and NJ analyses. However, the genetic distance between the sequences of the Korean alga and the two species is 1.3-1.9%, while that between the Korean alga and C. lucasii from Japan is 1.1% within intraspecific range. The divergence value between the Korean alga and C. lucasii from the type locality (Australia) is 2.7% considered to be interspecific range. As based on this genetic divergence value, the Korean alga together with Japanese C. lucasii can be separated from genuine C. lucasii from the type locality. However, the Korean alga is identified as C. lucasii until those entities are morphologically characterized in species level. This is the first record of C. lucasii in Korea

• Korean Journal of Plant Taxonomy
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• v.46 no.1
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• pp.124-127
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• 2016

Carex poculisquama $K{\ddot{u}}k$., recorded only in the literature in Korea, was confirmed to be distributed in limestone zones in the country. Carex poculisquama is most similar to species in the section Occlusae, such as C. ligulata Nees, but it differs in its rhombic-elliptic perigynium and by the presence of short hairs on the veins of its utricles. We provide here a description, illustrations, and photographs of C. poculisquama and a key to the species.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.213-218
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• 2006

The study of genetic diversity and population structure was carried out in the Codium fragile using allozyme analysis. Although this species has been regarded as a ecologically and economically important source, there is no report on population structure in Korea. Starch gel electrophoresis was used to investigate the allozyme variation and genetic structure of four Korean populations of this species. Of the 15 genetic loci surveyed, nine (60.0%) was polymorphic in at least one population. Genetic diversity was high at the species level ($H_{ES}$=0.144), and, that of the population level was relatively low ($H_{EP}$=0.128). Nearly 87% of the total genetic diversity in C. fragile was apportioned within populations. The predominant asexual reproduction, population fragmentation, low fecundity, geographic isolation and colonization process are proposed as possible factors contributing to low genetic diversity in this species. The indirect estimated of gene flow based on $G_{ST}$ was 1.69. The moderate level of gene flow in C. fragile populations is mainly caused by thallus developed from isolated utricles dispersal via sea current.

• Korean Journal of Medicinal Crop Science
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• v.11 no.2
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• pp.109-114
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• 2003

To determine the optimum N rate m Jeju island for utricle and root production of Achyranthes japonica Nakai, a medicinal plant, the plants were grown at two plant densities $(50\;and\;100\;hills/m^2$, two plants per hill; mall plots) at six N application rates (0, 6, 12, 18, 24, and 30 kg/10a; split plots) in 2001. There was no significant interaction between plant density and N application rate for all measured agronomic characters. Main root length and roots per hill were 5 and 52% greater, respectively, but N content of stover was lower under lower plant density compared to higher plant density. The other characters were not affected by plant density. N application rate did not significantly affect mall stem diameter, spikes per hill, spike length, utricles per spike, mall root length and diameter, and utricle N content. As N rate increased from 0 to 30 kg/10a, SPAD values and stover N content increased linearly from 35.0 to 40.5 and 1.09 to 1.38%, respectively, and plant height, branches per hill, stover, utricle and root dry matter yields, roots per hill, and top N yield increased quadratically. Spikes per hill were increased in a cubic manner with increased N application rates. N application rate for the maximum dry matter yield of utricle and root in A. japonica was estimated to be 21 kg N/10a.