• Korean Journal of Plant Taxonomy
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• v.35 no.4
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• pp.247-272
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• 2005

The Philadelphus schrenkii complex including P. schrenkii var. schrenkii, P. schrenkii var. jackii, P. schrenkii var. mandshuricus, P. tenuifolius, P. pekinensis, P. seoulensis, P. lasiogynus, and P. scaber, is distributed in China, Korea, japan, and far eastern Russia. Their taxonomic delimitations are obscure because quantitative characters, such as presence/absence and density of hair on leaf, petiole, style, disc, calyx-tube, and pedicel, are highly variable with no apparent characteristics that consistently distinguish from each other within the group. Thus, these morphological characters are reexamined using univariate analyses. P. pekinenesis is distinct from other taxa in having glabrous disk, calyx, pedicel, and leaf blade. In addition, the number of flowers in an inflorescence [(5)7-9(11) vs 5-7 in other taxa], smaller calyx tube [2.5-3 mm vs. (2.5)3-4(5.9) in other taxa], and slightly divided styles help distinguish P. pekinenesis from other related taxa in Korea. However, P. schrenkii var. schrenkii, P. schrenkii var. jackii, P. schrenkii var. mandshuricus, and P. lasiogynus show continuous variation in the pubescence of disk, calyx, pedicel, and leaf blade, and this may reflect a lack of divergence among them. Particular emphases are placed on P. tenuifolius and P. seoulensis, because of the high degree of morphological intergradation with respect to the degree of pubescence in disk, calyx, pedicel, and leaf blade and their inconsistent circumscription across various systematic treatments. P. scaber, distributed in the southern Korea, has often been treated as an independent species having exfoliated branchlets, distinct serrated leaf margin, and recurved styles. However, this current study suggests that P. scaber should be recognized as a form of P. tenuifolius because these distinguishing characters are continuous between P. tenuifolius and P. scaber. In geographical distribution, P. pekinensis is mainly distributed in the southern part of Korea, while P. tenuifoilus and P. schrenkii are commonly found all over the country.

• Korean Journal of Poultry Science
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• v.16 no.2
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• pp.83-89
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• 1989

This study was conducted to estimate heritabilities, genetic and phenotypic correlations on egg compositions in layers. The data analysis were a total of 6,097 eggs in S. C. W. Leghorn and R. I. Red from March 1, 1980 to July 31, 1981. The results obtained are summarized as follows； 1. The average albumen weight at first egg, 300 and 500 days of age were 28.67, 36.25 and 37.51g in the S. C. W. Leghorn, and 28.95, 36.01 and 36.85g in the R. I. Red, respectively. The yolk weigh at first egg ,300 and 500 days were 9.21, 15.94 and17.86g in the S. C. W. Leghorn,9.46, 16.43 and 18.54g in the R. I. Red, respectively. The shell weight at first egg, 300 and 500 days were 4.04, 5.39 and 5.40g in the S. C. W. Leghorn, and 3.66, 5.13 and 5.28g, respectively. 2. The heritability estimates based on the variance of sire and dam components were 0.631-0.164 and 0.412-0.496 in the S. C. W. Leghorn,0.234-0.563 and 0.477-0.610 in the R. I. Red for albumen weight； 0.213-0.530 and 0.343-0.613 in the S. C. W. Leghorn, 0.253-0.437 and 0.389-0.477 in the R. I. Red for yolk weight； 0.427-0.602 and 0.336-0.409 in the S. C. W. Leghorn, 0.141-0.281 in the R. I. Red for shell weight, respectively. 3. The genetic correlation coefficients of egg compositions were as follows； In the S. C. W. Leghorn and R. I. Red, the coefficients between albumen weight and yolk weight, 0.082-0.339 and 0.142-0.465； between albumen weight and shell weight, 0.674-0.952 and 0.216-0.546； between yolk weight and shell weight,0.173-0.171 and 0.121-0.749, respectively.

• Journal of Aquaculture
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• v.8 no.4
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• pp.295-306
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• 1995

The present study was performed to produce supermales and superfemales in Oreochromis niloticus by combination of induced sex reversal and diploid gynogenesis. More than $95\%$ of female was obtained by oral administration of $17\beta-estradiol$ (480 mg/kg diet) to the eutheroembryonic larvae of this species. The result of progeny tests with XY pseudofemales showed that incidences of male progeny were ranged from $71.4\%\;to\;73.7\%$. p.opo.lion of male from XY pseudofemale was not significantly different (P>0.05) from that of $\chi^2$ (1:3), but it was significantly different (P<0.01) from that of $\chi^2$(1:1) Gynogenetic diploids were produced by applying cold shocks 3 min after insemination to the eggs of XY pseudofemale sperms were genetically inactivated by ultraviolet rays of 4,050 $erg/mm^2$. Fertilization rates of gynogenetic diploids were not different from that of their controls, however, hatching rates and early survival rates were silghtly lower than those of controls. In the cytogenetic studies, there was no difference in the size of cell and nucleus between the gynogenetic diploids and the controls. At 80 days after hatching, frequencies of gynogenetic male were higher than those of gynogenetic female (P<0.01) in their population.

• Journal of Plant Biology
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• v.37 no.2
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• pp.203-221
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• 1994

Pollen grains of 19 taxa belonging to 12 genera in 5.families of the Korean gymnosperms were investigated by LM, SEM and TEM, and their morphological characters were described and palynological keys were made for each family. From the taxonomic viewpoint, palynological characters are very available to intergeneric and intrageneric classifications since their distinctive differences in pollen shape, size, condition of surface, sculpture pattern and presence of air bladders and projection except for the intrageneric classification of the genus Pinus since the overlapped characters such as pollen size and sculpture pattern. Pollen grains of Picea koraiensis in the family Pinaceae are distinguished from thc genera Pinus and Abies for the reasons that shape of air bladders are irregular, air bladders are bigger than pollen body, and pollen wall is thin. Compared with the genera Abies and Pinus that have air bladders, Picea koraiensis is closely related to Abies in that pollen body wall become gradually thin from pole of proximal face to air bladder, surface of pollen body is not rough, and pollen size is similar to that of the genus Abies. The presence of ektexine and enexine in proximal face, and the connections of the former to air bladder wall and the latter to distal face were elucidated by the investigation of pollen grains with air bladders through TEM. Endexine of the families of Taxaceae, Taxodiaceae and Cupressaceae was also obse-rved as a pile of laminae. From the observation by SEM, sculpture pattern of air bladder was foveolate with fine pits on surface. Sculpture pattern of air bladder is reticulate under LM, but observed by TEM, it resulted from the transmission of netted structure in air bladder.

• Journal of Aquaculture
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• v.19 no.4
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• pp.281-287
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• 2006

Intraspecific diploid androgenesis was achieved in mud loach (Misgurnus mizolepis) by the inhibition of the first mitotic division using combined thermal treatment. A combined thermal treatment (heat shock at $40.5\;^{\circ}C$ for 120 sec followed by cold treatment at $1\;^{\circ}C$ for 45 min) applied to the 1st metaphase of cell division (28 min post insemination at $25\;^{\circ}C$) successfully recovered viable androgenetic diploidy. Mean hatching success of the androgenetic diploid group was 29.6%, and the average yield out of total eggs taken was about 7% assessed at 1 week of age. However, relatively large variations in the yield of diploid androgenesis were observed among different egg batches used as cytoplasmic donors. Successful diploidization was confirmed by flow cytometric analysis, and parthenogenic reproduction in a paternal exclusive manner was verified with transgene dosage. Significant mortality was found in most androgenetic groups especially from hatch to 1 month of age, although such mortality was stabilized later.

• Korean Journal of Ichthyology
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• v.18 no.4
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• pp.339-346
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• 2006

In this study we conducted artificial hybridization between two sibling species, Rhodeus uyekii and R. notatus, and observed the morphological characteristics in early developmental stage. The two species showed difference in egg shape having rhombus and club respectively. The morphology of yolk of larva just hatched also showed well specific characteristics, that is the bean chaff type for R. uyekii (U type) and anchor type for R. notatus (N type). The rate of fertilization between female R. uyekii and male R. notatus (UN type) and between female R. notatus and male R. uyekii (NU type) were complete and its hatching rate were very high, 71.6% for UN type and 97.5% for NU type. The differences occurred in the yolk shape of hatched larvae for each combination of hybrids. In the group of UN, U type of larvae were found very rarely, but almost all the larvae showed intermediate shape polarized to NN type. Similar phenomenon was observed in the NU having intermediate polarized to UU, but without any NN type. These hybrids will be analyzed for their external morphology, sex ratio, the function of sexual organ and karyology after they grown up to adult.

• Journal of Life Science
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• v.14 no.5
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• pp.809-814
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• 2004

To investigate the effect of the electrolyzed acidic water for soybean sprouts growth, the responses of characteristics of soybean sprouts were evaluated. Soybean sprouts grown by the electrolyzed acidic water showed shorter length in total body, root, and hypocotyl, etc. but they were evaluated to be increased in hypocotyl diameter and weight per sprout. Total length of soybean sprouts grown for 5 days by electrolyzed acidic water were much shorter than those by tap water. Soybean sprouts grown by tap water showed rapid growth in length even after 5 days but no more growth in length for those grown by electrolyzed acidic water. The growth of hypocotyl showed the same tendency as total length. No difference in root length among the soybean sprouts grown for 4 ~ 11 days by electrolyzed acidic water while those grown by tap water showed continuous rapid growth in length. The diameter of hypocotyl was thicker in those grown by electrolyzed acidic water than those grown by tap water and increased up 5 days. The weight of cotyledon grown by electrolyzed acidic water showed the proportional increase to the growing days but those grown by tap water showed no increase in hypocotyl weight up to 7 days, but a little bit increase after 11 days with the growth of new buds. The fresh weight per sprout was higher in those grown by electrolyzed acidic water until 7 days than tap water but it was the same weight in 11 days cultivation. The electrolyzed acidic water effected on shortening of hypocotyl and root length, thickening of hypocotyl diameter, and enlarging of cotyledon during soybean sprout cultivation.

• Korean Journal of Ichthyology
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• v.22 no.1
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• pp.25-33
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• 2010

Effects of different salinity levels on spawning performance, embryonic development and early viability of a euryhaline medaka species, Oryzias dancena, were examined. O. dancena were able to spawn eggs in a wide range of salinity from 0 to 70$^{\circ}/_{\circ\circ}$, however, the spawning frequency was lowered in complete freshwater (0$^{\circ}/_{\circ\circ}$) and in highly salted water (70$^{\circ}/_{\circ\circ}$). Fertilization success was negatively affected when the environmental salinity was higher than the salt concentration found in normal seawater. Embryonic viability and hatching success were also inversely related with the salinity levels. Typical abnormality was observed in developing embryos incubated at high salinities (30, 45 and 60$^{\circ}/_{\circ\circ}$). In addition, the time to hatch was significantly delayed with increasing salinities: peak hatching occurred at 12~14 days post fertilization (dpf) in freshwater and at least at 17 to 18 dpf in 60$^{\circ}/_{\circ\circ}$. Mean survival rates of the hatched larvae up to 7 days post hatching (dph) were at least 97% in salinity levels ranging from 0 to 30$^{\circ}/_{\circ\circ}$. However, larvae reared in 45 and 60$^{\circ}/_{\circ\circ}$ experienced significant mortality, especially in the early phase, resulting in only 75% and 64% survival rates up to 7 dph, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.4
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• pp.283-290
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• 2010

Guineagrass (Panicum maximum Jacq.) is an important warm-season forage grass as well as biomass crop. It has both sexual and asexual mode of reproduction (apomictic) depending on cultivar. We developed efficient plant regeneration system for an apomictic (cv. Natsukaze) and a non-apomictic (Noh-PL1) guineagrass by optimizing the level of L-proline in the callus induction and that of $AgNO_3$ in plant regeneration medium. Among the L-proline concentrations tested, the best callus induction was achieved by using 2g/L L-proline in both the genotypes. Immature embryos proved to be the best explant source for tissue culture of guineagrass. The highest frequency of shoot regeneration was obtained on MS plant regeneration medium supplemented with 2 mg/L $AgNO_3$. These results provide a foundation for efficient tissue culture and genetic improvement of guineagrass.

• Applied Microscopy
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• v.37 no.2
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• pp.65-72
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• 2007

The oogenesis and ultrastructure of fertilized egg envelope of false dace were investigated by light and electron microscope. The cytoplasm of false dace oogonia was basophilic and many nucleoli were located at inner side of nuclear membrane. In primary oocytes, yolk vesicles were distributed in marginal area only and egg envelope was not formed on egg outside. In secondary oocyte, the egg envelope was formed and yolk vesicles were increased than that of early stage in cytoplasm. The amount of basophilic substance was decreased. In case of matured egg, thickness of egg envelope and site of egg were increased, basophilic substance was distributed in egg envelope around only. The yolk vesicles were changed to yolk mass in accordance with development. The fertilized egg was of ellipsoidal, adhesive type and yellowish, have a single micropyle in the area of the animal pole. The fertilized egg envelope consisted of three layers, an outer adhesive layer, a middle layer consisting of 6 lamellae alternating layers and an inner electron dense layer. An outer surface of the fertilized egg envelope was arranged by adhesive fibrous structures. In conclusion, it is summarized that the oogenesis of false dace were the increase of cell size, the formation and accumulation of yolk, and decrease of basophilic intensity in cytoplasm. These ultrastructural characteristics of fertilized egg envelope from false dace can be utilized in taxonomy of teleost.