• Journal of the Korean Applied Science and Technology
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• v.15 no.4
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• pp.1-9
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• 1998

The lipids from the seeds of Pinus koraiensis mostly composed of triacylglycerols (TGs), in which linoleic acid (46.2 mol%) and oleic acid (25.6 mol%) are present as main components in the fatty acid composition. Surprisingly, they also have unusual fatty acids with ${\Delta}^5$-double bond systems such as ${\Delta}^{5.9.12}-C_{18:3}$ (16.0 mol%), ${\Delta}^{5.9}-C_{18:2}$ (2.3 mol%) and ${\Delta}^{5.11.14}-C_{20:3}$ (0.8 mol%). Saturated fatty acids of palmitic, stearic and arachidic acid were present in less than 8.0 mol%. TG was resolved into 17 fractions by reverse-phase HPLC according to so-called partition number (PN) suggested by Plattner, in which TG molecules with ${\Delta}^{5}$-NMDB acyl chains eluted later than did those with ${\Delta}^{9}$-MDB acyl radicals. $Ag^+$-HPLC separated the TG into 14 fractions more clearly than did those with ${\Delta}^{9}$-MDB acyl radicals. $Ag^+$-HPLC separated the TG into 14 fractions more clearly than did reverse-phase HPLC, and the complexity of ${\Delta}^{5.9.12}-C_{18:3}$ moiety with silver ion impregnated in the column bed was in the level between ${\Delta}^{9.12.15}-C_{18:3}$ ($C_{18:3{\omega}3}$) and $C_{18:2{\omega}6}$ (${\Delta}^{9.12}-C_{18:2}$). In the $Ag^+$-HPLC, it was found that the molecular species having a given-numbered double bonds widely spreaded in the acyl chains eluted earlier than those concentrated in one acyl chain. The main molecular species are $(C_{18:2{\omega}6})_2/{\Delta}^{5.9.12}-C_{18:3}$ (14.8 mol%), $C_{18:1{\omega}9}/C_{18:2{\omega}6})_2$ (12.8 mol%) and $C_{18:1{\omega}9}/C_{18:2{\omega}6}/{\Delta}^{5.9.12}-C_{18:3}$ (10.9 mol%).

• Korean Journal of Plant Resources
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• v.24 no.5
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• pp.628-635
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• 2011

This study was conducted to establish the tissue culture system for Korean domestic Miscanthus sinensis, which is used in various purposes such as forage, and bio-energy resources. With the mature seed of Miscanthus, optimum concentrations of plant growth regulators were identified for an efficient callus induction and regeneration. Among the treatments of 1~10 $mg{\cdot}L^{-1}$ 2,4-D, IBA, or NAA, callus induction rate was highest (85.3%) on MS medium containing 5 $mg{\cdot}L^{-1}$ 2,4-D. Under the condition, the callus were efficiently induced and proliferated with comparably lower frequencies of callus browning. In shoot regeneration, the treatment of NAA combined with BAP seemed to contribute more efficient conditions to shoot regeneration than those of NAA with Kinetin or 2-iP. Especially, regeneration efficiency and number of regenerated plants were 83.7% and 5.5 in 3 $mg{\cdot}L^{-1}$ NAA with 5 $mg{\cdot}L^{-1}$ BAP, respectively, which were higher frequencies than those in NAA with Kinetin or 2-iP. In results, 5 $mg{\cdot}L^{-1}$ 2,4-D and 3 $mg{\cdot}L^{-1}$ NAA combined with 5 $mg{\cdot}L^{-1}$ BAP were efficient for embryogenic callus induction and regeneration of Miscanthus. This system would be useful for mass-propagation and developing new cultivars via tissue culture of Miscanthus sinensis.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.49-55
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• 1978

In order to get healthy seedling of rice suitable for rice transplanter, the growing characteristics of the seedling grown under different growing days and sowing densities were invesigated and the results obtained were summarized as follows; In the 20 days old seedling, the difference of growing state of seed ling and its characteristics between the two types of nursery bed was not found, but for the 30 days old seedling, both of the crop growth rate and the relative growth rate on the band-type nursery bed appeared higher than those on the mat-type nursery bed. And also, "the dry weight, the content of cardohydrate and the ratio of dry weight to plant height of the seedling grown on the band-type nursery bed were much higher than those on the mat-type nursery bed, however the amount of difference of seedling characteristics between two types of nursery bed was decreased for 40 days old seedling and leaf number was not increased. The amount of the seedling growth was increased with less density of sowing and for the difference between the higher and the less density, the difference getting bigger with the longer nursery days. The maximum density of sowing was approximately 200cc per nursery case on the band-type nursery bed and 250cc per nursery case on the mat-type nursery bed. It was seemed that the growing uniformity of the seedling grown on the mat-type nursery bed was better than that on the band- type nursery bed, As the coefficient of variation of the plant height and the leaf numbers of the seedling grown on the band- type nursery bed was higher than that on the mat-type nursery bed.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.44.3-45
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• 2017

To date, luminous quasars at z ~ 6 have been found to be in maximal accretion with the Eddington ratios, ${\lambda}Edd$ ~ 1, suggesting enhanced nuclear activities in the early universe. However, this may not be the whole picture of supermassive black hole (SMBH) growth since previous studies have not reached on faint quasars that are more likely to harbor SMBHs with low ${\lambda}Edd$. To understand the accretion activities in quasars at high redshift, we obtained the deep near-infrared (NIR) spectrum of a quasar, IMS J2204+0112, one of the few faintest quasars that have been identified at z ~ 6. From the NIR spectrum, we find that IMS J2204+0112 harbors a SMBH with about a billion solar mass, with ${\log}({\lambda}Edd)=-0.91$. This is the lowest accretion rate found so far for quasars at z ~ 6, but a common value among quasars at z ~ 2. The inclusion of this object in the ${\lambda}Edd$ analysis gives the intrinsic ${\lambda}Edd$ distribution of z ~ 6 quasars, which is lower than previous results that are based on bright quasars, but it is still higher than ${\lambda}Edd$ of z ~ 2 quasars. Although the number statistics needs to be improved in future, the low peak ${\lambda}Edd$ value is consistent with the SMBH growth from a massive black hole seed (~ 105 Msun) or from a stellar mass black hole through short-duration super-Eddington accretion events (${\lambda}Edd$ > 10).

• Molecules and Cells
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• v.24 no.1
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• pp.83-94
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• 2007

During monocarpic senescence in higher plants, functional stay-green delays leaf yellowing, maintaining photosynthetic competence, whereas nonfunctional stay-green retains leaf greenness without sustaining photosynthetic activity. Thus, functional stay-green is considered a beneficial trait that can increase grain yield in cereal crops. A stay-green japonica rice 'SNU-SG1' had a good seed-setting rate and grain yield, indicating the presence of a functional stay-green genotype. SNU-SG1 was crossed with two regular cultivars to determine the inheritance mode and identify major QTLs conferring stay-green in SNU-SG1. For QTL analysis, linkage maps with 100 and 116 DNA marker loci were constructed using selective genotyping with $F_2$ and RIL (recombinant inbred line) populations, respectively. Molecular marker-based QTL analyses with both populations revealed that the functional stay-green phenotype of SNU-SG1 is regulated by several major QTLs accounting for a large portion of the genetic variation. Three main-effect QTLs located on chromosomes 7 and 9 were detected in both populations and a number of epistatic-effect QTLs were also found. The amount of variation explained by several digenic interactions was larger than that explained by main-effect QTLs. Two main-effect QTLs on chromosome 9 can be considered the target loci that most influence the functional stay-green in SNU-SG1. The functional stay-green QTLs may help develop low-input high-yielding rice cultivars by QTL-marker-assisted breeding with SNU-SG1.

• Research in Plant Disease
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• v.13 no.3
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• pp.191-196
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• 2007

An isolate of Ampelomyces quisqualis 94013(AQ94013) was selected as an effective agent for biological control against cucumber powdery mildew. In order to develop mass production technique, six cereal media made with barley, rice, mille and brown rice, sorghumand rice seed were tested. Among them, barley medium was the best for the growth and conidial production of AQ94013. Optimum temperature for the mass production of AQ94013 was $25^{\circ}C$ and followed by $20^{\circ}C$ and $30^{\circ}C$. Light radiation inhibited conidial production of AQ94013 since number of conidia formed on barely medium under continuous light or 12 hrs alternative light were much less than cultured in darkness. Tthe conidia produced on the medium at $30^{\circ}C$ maintained the parasitic ability to Sphaerotheca fusca for 30 days. A culture method of AQ94013 in barley liquid medium with adding barely power(40 g/l) in darkness for five days at $25^{\circ}C$using a 30 l-fermenter was very effective for mass production of conidia.

• Korean Journal of Agricultural Science
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• v.11 no.1
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• pp.68-76
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• 1984

The study was conducted to investigate an optimum growing condition for various sizes of seedlings of rice for mechanical transplantation under different sowing rates, different levels of fertilizers, different sowing dates and g rowing days. The plant height, leaf number and dry weight of seedlings increased as the sowing rate decreased and amount of fertilizer applied were increased. Also those seedling characters increased as the rice planted late and the total growing periods increased. The factors affected seedling chracters were ordered as following-sowing times>growing days>sowing rate>fertilizer levels. 200 gr. of seeds per box and 4 gr. of fertilizers were optimum for young seedling growth, when sown early. For medium size of seed ling growth, 50 grams and 100 to 125 grams of rice seemed to be adequate for 25 days old and 35 days old seedling, respectively. However, the 45 days old seedling grew too mach and were not suitable for mechanical transplantation. When planted late, similar results were obtained with more differences among treatments. In other words, the suitable plant density was obtained when 100 gr. of seeds were planted per box. Middle class of seedlings were obtained when 100 to 150 gr. of rice were planted per box and grown for 25 days. The seedlings from the box with 100 to 150 gr. of rice per box were over grown and ratio of suitable seedling was also low if they were grown over 35 days.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.658-675
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• 2016

The environmental characteristics of the habitats, the population structures, ecological niche, life traits and the population demography are used as an essential informations to the effective conservation plans about the target species. We first confirmed a total of 37 populations through 12 years of investigation on the extents, and investigated the environmental factors of habitats and the population structures of the 25 cohorts in 12 regions among them. And, we investigated the population dynamics targeting at 8 cohorts in the population of Daegwanryeong-myeon, Pyeongchang-gun, Gangwon-do. Along with this, we conducted 4 years of cultivation experiments and how pollinators affect the success of reproduction. The results shows that the Paeonia obovata Maxim. was found in a relatively wide range of habitats. For the population structures of the 25 cohorts, there were considerable differences among cohorts, including a case which showed relative stable structure and an extreme case in which only adults were found. The factor that affected the population dynamics during the investigation was thought as a forest gap created in the tree layer. In the cultivation experiment, seedlings grew well in a less soil organic matter. The seed setting rate and the number of seeds generated by visiting pollinators were higher trends. In conclusion, to understand the distribution of the Paeonia obovata Maxim., there needs to be investigated on the other factors that are involved in dispersal factors other than environmental factors, and thus we suggest the necessity of the research on the dispersal vectors. The current Paeonia obovata Maxim. population was thought as a process of expansion after the rapid reduction of the extents in the past. For the effective conservation of the Paeonia obovata Maxim., an endangered plant, we recommend to understand the species through the spatio-temporal expansion, and maintain the health of the ecosystem based on it.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.333-337
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• 2006

The damage aspects of soybean by common cutworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) at different larval density and different growth stage of soybean were studied in soybean field. The percent yield reduction(Y) of soybean infested by different densities of S. litura (X, no. of larvae/plant) under outdoor conditions for a three week period were estimated by the following equations: (1) Y = 1.655X - 6.025 ($R^{2}=0.952$) for the R1 (flowering stage); (2) Y = 0.725X - 0.475 ($R^{2}=0.986$) for the R3 (beginning pod stage); and (3) Y = 0.635X - 1.325 ($R^{2}=0.986$) for the R5 (beginning seed stage). Based on the relationships between the densities of S. litura larvae and the yield index of soybean, the number of larvae (2nd-3rd instar) which caused 5% loss of yield (Tolerable injury level) was estimated to as approximately 6.7 for the R1, 7.5 for the R5, and 10.0 per plant for the R5, respectively. Average soybean leaf areas consumed by 1st, 2nd, 3rd, 4th, 5th and 6th larvae of Spodoptera litura during 24 hr at $28^{\circ}C$ was 0.3, 0.7, 2.6, 4.0, 20.1, and $55.8\;cm^{2}$, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.1 no.1
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• pp.3-25
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• 1963

Experiments were carried out to classify the ecotypes and maturity groups of soybean varieties, and to make clear the relationships among these ecotypes, maturity groups and some characteristics in the growing and ripening process of soybean varieties in Korea. Soybean varieties used as the material were 138, 57 varieties collected from Japan, America and Canada and 81 local varieties of Korea. These varieties were grown in the Experimental Farms, College of Agriculture, Seoul National University, Suwon, Korea and Chinju Agricultural College, Kyungsang Namdo, Korea. Seed sowing was conducted at 8 times from April15 to July 29, at 15 day-intervals, in 1962. The classification methods of ecotypes and maturity groups applied in this study, and the results obtained are summarized as follows; 1. Ecotypes were classified from the standpoint of the periods from emergence to flowering, the shortened ratio of days from sowing to flowering by delayed sowing, and the periods from flowering to maturity(as shown in Table A). 2. All varieties wer classified into 10 ecotypes of Ia$_1$, Ib$_1$, IIa$_2$, IIb$_1$, IIb$_2$, IIIb$_1$IIIb$_2$, IIIc$_1$and IIIc$_2$ symbols. Korean local varieties, however, belong to 6 ecotypes of IIb$_1$, IIb$_2$, IIIb$_1$, IIIc$_2$, IIIc$_1$ and IIIc$_2$, respectively(table 1). 3. Durations from sowing to maturity were from 120 to 190 days in April sowing plots of all varieties. From the standpoint of the durations, maturity groups were classified into 9 groups from group I, extreme early, to group IX, extreme late, but our local varieties belong to 5 maturity groups of III, IV, V, VI and VII symbols, respectively(Table 2). 4. Kinds of ecotypes and maturity groups, and the number of soybean varieties belonging to those are as shown in Table B. 5. In this study, it was observed that there were some close relations between these ecotypes and maturity groups (Table 3,4), and among the ecotypes, maturity groups and some other characteristics in the growing and ripening process of the soybean varieties(Table 5). 6. Furthermore, it was also observed that the kinds of ecotypes and maturity groups of recommended varieties in the southern Korean provinces are more numerous than those of the northern provinces in Korea.