• Title/Summary/Keyword: B16f10

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Studies on the Chemical composition of Citrus fruits in Korea (III) -On the free amino acids , sugars and pectin content in main Varieties- (한국산(韓國産) 감귤류(柑橘類)의 화학성분(化學成分)에 관(關)한 연구(硏究)(III) -주요(主要) 감귤(柑橘) 품종별(品種別) 유리(遊離) amino acid, 당(糖) 및 pectin 함량(含量)에 관(關)하여-)

  • Park, H.;Yang, C.B.;Kim, Z.U.;Lee, C.Y.
    • Applied Biological Chemistry
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    • v.9
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    • pp.97-104
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    • 1968
  • A survey of the free amino acids and free sugars in the juice of fourteen citrus varieties was made by means of paper chromatography and the pectin content in the rind was detected The results of the survey are summarized as follows. 1) Sixteen aminoacids detecteu in fourteen varieties under the condition of this study were distributed with. different frequency as follow. Proline, gamma-amino-butyric acid, alanine, valine, serine, glutamic acid, aspartic acid (in 14 varieties), lysine(12), leucine threonine(11), isoleucine(10), arginine(9), glycine(6) ${\beta}-alanine$(4) asparagine(3) unknown(2). 2) Proline, gamma-amino-butyric acid were mostly abundant in all varieties and alanine was next in the amount. 3) The varieties in the decreasing order of number of amino acids container were C. grandis madow C. leiocarpa (14 acids), C. sulcata, C. hassaku. native citron, Fortunella japonica(13) C. grandis heiko, C. Tamurana iyo, C. nobilis(12) C. reticulata C. junos(11) C. natsudaidai(10) C. miyakawa unshiu, C. ohali unshiu(9). 4) The varieties which appear to contain all essential amino acids(6 acids)detected were C. grandis madow C. grandis heiko, C. sulcata, C. Tamurana iyo, C. hassaku and native citron, and C. natsudaidai, C. unshiu were the least (1-3 acids). 5) Glucose fructose, sucrose and maltose were detected in all varieties. 6) The pectin content in the rind ranged from 8.64% F.W.(C. junos) up to 17.0% for C, grandis madow and the mean was $11.63{\pm}2.69%$.

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A Study of the Whitening Activities of Magnolia obovata Bark Ethyl Acetate Fractions as Cosmetic Ingredient (화장품 소재로서 후박 에틸아세테이트 분획물의 미백활성에 관한 효과)

  • Kang, Hee Cheol;Joo, Kwang Sik;Joo, Se Jin;Ha, Young Ae;Kim, Hack Soo;Cha, Mi Yeon
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.43 no.1
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    • pp.43-52
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    • 2017
  • EtOAc fractions of Magnolia obovata (M. obovata) Bark extracts were studied for the potential ingredient as a safe and effective whitening cosmetic material. The concentration of active substances honokiol was determined by HPLC. In vitro, the fractions reduced the extracellular and intracellular melanin contents in B16F10 cells in dose dependently and inhibited extracellular melanin secretion ($IC_{50}=11.05{\mu}g/mL$). The $12.5{\mu}g/mL$ treatment of maximum concentration effectively inhibited up to about 60% to the amount of extracullular melanin. Also, the $12.5{\mu}g/mL$ treatment of maximum concentration effectively inhibited up to about 59% to the amount of intracullular melanin ($IC_{50}=10.85{\mu}g/mL$). The $IC_{50}$ value of ${\alpha}-arbutin$ used as a positive control was $59.99{\mu}g/mL$. So, EtOAc fractions of M. obovata Bark extracts showed whitening effect when compared with the non-treatment group. In case of in vivo study, Cosmetic cream with EtOAc fractions of M. obovata Bark extracts was approved by Ethics committee of KDRI (IRB number: KDRI-IRB-1537). As a result in progress for skin sensitization as well as assessment of skin irritation through repeated patch test, skin allergens was identified as non sensitizing agents. Also, cosmetic cream with EtOAc fractions of M. obovata Bark extracts showed significant topical whitening effect and reliable skin safety when compared with the non-treatment group. In conclusion, EtOAc fractions of M. obovata Bark extracts may be a useful cosmetic ingredient for effective skin whitening.

Mitigation Effects of Foliar-Applied Hydrogen Peroxide on Drought Stress in Sorghum bicolor (과산화수소 엽면 처리에 의한 수수에서 한발 스트레스 완화 효과)

  • Shim, Doo-Do;Lee, Seung-Ha;Chung, Jong-Il;Kim, Min Chul;Chung, Jung-Sung;Lee, Yeong-Hun;Jeon, Seung-Ho;Song, Gi-Eun;Shim, Sang-In
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.65 no.2
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    • pp.113-123
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    • 2020
  • Global climatic change and increasing climatic instability threaten crop productivity. Due to climatic change, drought stress is occurring more frequently in crop fields. In this study, we investigated the effect of treatment with hydrogen peroxide (H2O2) before leaf development on the growth and yield of sorghum for minimizing the damage of crops to drought. To assess the effect of H2O2 on the growth of sorghum plant, 10 mM H2O2 was used to treat sorghum leaves at the 3-leaf stage during growth in field conditions. Plant height, stem diameter, leaf length, and leaf width were increased by 7.6%, 9.6%, 8.3% and 11.5%, respectively. SPAD value, chlorophyll fluorescence (Fv/Fm), photosynthetic rate, stomatal conductance, and transpiration rate were increased by 3.0%, 4.9%, 26.0%, 23.4% and 12.7%, respectively. The amount of H2O2 in the leaf tissue of sorghum plant treated with 10 mM H2O2 was 0.7% of the applied amount after 1 hour. The level increased to approximately 1.0% after 6 hours. The highest antioxidant activity measured by the Oxygen Radical Absorbance Capacity assay was 847.3 µmol·g-1 at 6 hour after treatment. However, in the well-watered condition, the concentration of H2O2 in the plant treated by the foliar application of H2O2 was 227.8 µmol·g-1 higher than that of the untreated control. H2O2 treatment improved all the yield components and yield-related factors. Panicle length, plant dry weight, panicle weight, seed weight per plant, seed weight per unit area, and thousand seed weight were increased by 8.8%, 18.0%, 24.4%, 24.7%, 29.9% and 7.1%, respectively. Proteomic analysis showed that H2O2 treatment in sorghum increased the tolerance to drought stress and maintained growth and yield by ameliorating oxidative stress.

Seasonal sea Level oscillations in the East Sea (Sea of Japan) (동해 해수면의 계절적인 변동에 대하여)

  • OH, IM SANG;RABINOVICH, ALEXANDER B.;PARK, MYOUNG SOOK;MANSUROV, ROALD N.
    • 한국해양학회지
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    • v.28 no.1
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    • pp.1-16
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    • 1993
  • The monthly mean sea levels at 48 stations located at the East and Yellow Seas coasts of Korea, Russia and Japan are processed to investigate seasonal sea level variations. The strong seasonal variations are found to be at the west coast of Korea (42.1 cm in Kunsan), in the region of the Korea strait and near the southern part of Primorye (30-33 cm); the weak ones near the southwestern coast of the Sakhalin Island (10-12 cm). Practically for the whole study area except the southwest Sakhalin, the general picture of the seasonal sea level changes is alike: the mean sea level rises in summer-autumn and falls in winter-spring. The spectral analysis of the records also shows that the seasonal oscillations strongly dominate in the sea level variations, more than 80% or total energy in the southern part of the investigated region and 50-70% in the northern part relate to these oscillations. The annal peak significantly prevails in spectra of the monthly sea levels for the majority of stations, the semiannual peak is also well manifested, but the seasonal peaks of higher order (corresponding to the periods of four and three months) reveal only at some records. The maximal amplitudes of annual component by a least square method are found at the Yellow Sea coast of Korea (20-21 cm) and also near the Japanese coast of the korea Strait (19-19 cm). The semiannual component has the maximal amplitudes (3-4 cm) near the south and southwestern coasts of the Sakhalin Island. The annual range of the sea levels is much weaker here than in the other regions, the relative investment of the seasonal oscillations in total energetic budget is only 35-40%, annual ($A_1$) and semiannual ($A_2$) components have nearly the same amplitude (seasonal factor $F=A_1/A_2=0.9-1.2$). On the basis of the present examination on sea level changes together with the results of Tomizawa et. al.(1984) the whole investigated area may be divided into 10 subregions, 2 of them are related to the Yellow Sea and Western part of the Korea Strait (Y1, Y2), the other ones (E1-E8) to the East Sea.

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Inhibitory Effects of Ethanol Extracts from Polygoni multiflori radix and Cynanchi wilfordii radix on Melanogenesis in Melanoma Cells (하수오와 백하수오의 에탄올 추출물에 의한 B16/F10 Melanoma 세포주의 멜라닌 생성 억제효과)

  • Seo, Hee;Seo, Geun-Young;Ko, Su-Zie;Park, Young-Hyun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.8
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    • pp.1086-1091
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    • 2011
  • Anti-oxidative activity and tyrosinase inhibitory activity of various ethanol extracts of Polygoni multiflori radix (PMR) and Cynanchi wilfordii radix (CWR) were compared to identify an anti-oxidant and whitening agent source from nature. We conducted an investigation into the anti-oxidant activities of PMR and CWR ethanol extracts by measuring total polyphenol content, total flavonoid content, and ABTS radical capacity. The total polyphenol contents of PMR and CWR were 17.31${\pm}$0.54 mg GA/eq g, and 2.75${\pm}$0.22 mg GA/eq g, respectively. The total flavonoid contents of PMR and CWR were 6.38${\pm}$0.39 mg naringine/eq g, and 1.34${\pm}$0.09 mg naringine/eq g, respectively. The 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical decolorization of PMR and CWR were 96.89${\pm}$0.21% at 1 mg/mL and 93.49${\pm}$0.76% at 50 mg/mL. Melanoma cells were cultured with the PMR and CWR ethanol extracts for 48 hr, and total melanin content as a final product and the activity of tyrosinase, a key enzyme, in melanogenesis, were estimated. The PMR and CWR ethanol extracts increased melanin content and tyrosinase activity in a dose-dependent manner. These results suggest that PMR and CWR ethanol extracts could be useful as a skin whitening agent.

Simultaneous Determination and Monitoring of Bisphenols in River Water using Gas Chromatography-Mass Spectrometry (GC-MS 를 이용한 하천수 중 Bisphenol계 화합물의 동시분석 및 모니터링)

  • Kim, Jihyun;Choi, Jeong-Heui;Kang, Tae-Woo;Kang, Taegu;Hwang, Soon-Hong;Shim, Jae-Han
    • Korean Journal of Environmental Agriculture
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    • v.36 no.3
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    • pp.154-160
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    • 2017
  • BACKGROUND:This study was carried out to establish an efficient sample preparation for the simultaneous determination of bisphenols (BPs) in river water samples using gas chromatography-mass spectrometry (GC-MS). Sample preparation was examined with conventional extraction methods, such as solid-phase extraction (SPE) and liquid-liquid extraction (LLE), and their efficiency was compared with validation results, including linearity of calibration curve, method detection limit (MDL), limit of quantification (LOQ), accuracy, and precision. METHODS AND RESULTS:The BPs (bisphenol A, BPA; bisphenol B, BPB; bisphenol C, BPC; bisphenol E, BPE; bisphenol F, BPF; bisphenol S, BPS) were analyzed using GC-MS. The range of MDLs by SPE and LLE methods was $0.0005{\sim}0.0234{\mu}g/L$ and $0.0037{\sim}0.2034{\mu}g/L$, and that of LOQs was $0.0015{\sim}0.0744{\mu}g/L$ and $0.0117{\sim}0.6477{\mu}g/L$, respectively. The calibration curve obtained from standard solution of $0.004{\sim}4.0{\mu}g/L$ (SPE) and $0.016{\sim}16{\mu}g/L$ (LLE) showed good linearity with $r^2$ value of 0.9969 over. Accuracy was 93.2~108% and 97.4~120%, and precision was 1.7~4.6% and 0.7~6.5%, respectively. The values of MDL and LOQ resulted from the SPE method were higher than those from the LLE method, particularly those values of BPA were highest among the BPs. Based on the results, the SPE method was applied to determine the BPs in river water samples. Water samples were collected from mainstream, tributary and sewage wastewater treatment plants (SWTPs) in the Yeongsan river basin. The concentration of BPB, BPC, BPE, BPF and BPS were not detected in all sites, whereas BPA was ranged $0.0095{\sim}0.2583{\mu}g/L$, which was $0.0166{\sim}0.0810{\mu}g/L$ for mainstreams, $0.0095{\sim}0.2583{\mu}g/L$ for tributaries, $0.0352{\sim}0.1217{\mu}g/L$ for SWTPs. CONCLUSION: From these results, the SPE method was very effective for the simultaneous determination of BPs in river water samples using GC-MS. We provided that it is a convenient, reliable and sensitive method enough to monitor and understand the fate of the BPs in aquatic ecosystems.

Effects of Senenium and Vitamin E Administration on the Semen Characteristics, Blood Chemical Values and Hormone in Hanwoo Sires I. Effects of Selenium, Vitamin E and rBST Administration on the Semen Characteristics in Hanwoo Sires (Selenium 과 Vitamin E 투여가 한우 종모우의 정액성상, 혈액성분 및 호르몬 변화에 미치는 효과 I. Selenium, Vitamin E 및 rBST 투여가 한우 종모우의 정액성상에 미치는 효과)

  • 양부근;전기준;김종복;박동헌;김정익;박춘근;이성수;박노형;원유석
    • Korean Journal of Animal Reproduction
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    • v.23 no.3
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    • pp.191-203
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    • 1999
  • The objectives of this study were to investigate 1) the effects of Selenium(Se), Vitamin E (Vit. E) or recombinant Bovine Somatotropin(rBST) administration on fresh and frozen/thawed semen characteristics and 2) the effect of taurine on frozen/thawed semen characteristics in Hanwoo sires Hanwoo sires were randomly assigned to five groups (1. control, 2. rBST, 0.09mg/kg body weight (BW), 3. Vito E 1,500IU/kg BW, 4. Se 0.l mg/kg BW, 5. Vit. E 1,500IU plus Se 0.1 mg/kg BW). The administration of Se, Vit. E and rBST for each experimental group were given 6 times at 15 days interval by intramuscular injection. The administration of Se, Vit. E or rBST in Hanwoo sires didn't affect semen volume and pH values, but sperm viability was significantly increased comparing to the control group. Also, frozen/thawed semen analysis showed that the sperm viability increased, but any other effects were not found in total sperm :lumber, motility and abnormality among treatments. The addition of taurine in semen freezing extender had a beneficial effects on frozen/thawecl semen characteristics in all groups. The administrations of rBST, Vit. E and Se did not affect the sperm capacitation and acrosome reaction, either the ratio of F pattern(uncapacitated and acrosome intact sperm) or AR pattern(capacitated and acrosome-reacted sperm), but the ratio of B patten(capacitated and acrosome intact sperm) of treatment groups was significantly higher than that of control group, These results indicated that the viability, motility and quality of semen in Hanwoo sires were slightly increased by the injection of rBST, Vit. E and Se, and the addition of taurine in semen freezing extender were also increased the semen characteristics after thawing.

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Development of Natural Antioxidants and Whitening Agents for Cosmeceuticals

  • Kim, Jong-Pyung
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2007.11a
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    • pp.79-92
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    • 2007
  • Oxidative stress have known to be a risk factor for the degenerative processes and closely related to a lot of diseases. It is well established that antioxidants are good in protection and therapeutic means against oxidative damage. There is increasing interest in natural antioxidants and many natural antioxidants have been found and utilized as the possible protection for various diseases and skin aging. We have screened natural antioxidant agents for cosmeceuticals, nutraceuticals, and drugs as therapeutic and preventive means against oxidative stress, and have developed a number of novel antioxidants from various natural sources. A novel melanin synthesis inhibitor, Melanocin A, isolated from the metabolite of a fungal strain Eupenicillium shearii F80695 inhibited mushroom tyrosinase and melanin biosynthesis of B16 melanoma cells with $IC_{50}$ value of 9.0 nM and MIC value of $0.9\;{\mu}M$, respectively. Melanocin A also exhibited potent antioxidant activity by scavenging of DPPH and superoxide anion radicals. UV was found to increase the level of hydrogen peroxides and other reactive oxygen species (ROS) in skin tissues. This increase in ROS may not only alter the structure and function of many genes and proteins directly but may also modulate their expressions through signal transduction pathways and, ultimately, lead to skin damage. We investigated the effect of Melanocin A on UV-induced premature skin aging. Firstly, the effect of Melanocin A on UV-induced matrix metalloproteinase (MMP)-9 expression in an immortalized human keratinocyte cell line, HaCaT in vitro was investigated. Acute UV irradiation induced MMP-9 expression at both the mRNA and protein levels and Melanocin A suppressed this expression in a dose-dependent manner. We then investigated UV-induced skin changes in hairless mice in vivo by Melanocin A. Chronic exposure of hairless mouse dorsal skin to UV increased skin thickness and induced wrinkle formation and the gelatinase activities of MMP-2 and MMP-9. Moreover, Melanocin A significantly suppressed UV-induced morphologic skin changes and MMP-2 and MMP-9 expression. These results show that Melanocin A can prevent the harmful effects of UV that lead to skin aging. Therefore, we suggest that Melanocin A should be viewed as a potential therapeutic agent for preventing and/or treating premature skin aging. Terrein is a bioactive fungal metabolite isolated from Penicillium species. Terrein has a relatively simple structure and can be easily synthesized. However, the biologic effects of terrein are comparatively unknown. We found for the first time that terrein potently inhibit melanin production in melanocytes and has a strong hypopigmentary effect in a spontaneously immortalized mouse melanocyte cell line, Mel-Ab. Treatment of Mel-Ab cells with terrein (10-100 mM) for 4 days significantly reduced melanin levels in a dose-dependent manner. In addition, terrein at the same concentration also reduced tyrosinase activity. We then investigated whether terrein influences the extracellular signal-regulated protein kinase (ERK) pathway and the expression of microphthalmia-associated transcription factor (MITF), which is required for tyrosinase expression. Terrein was found to induce sustained ERK activation and MITF down-regulation, and luciferase assays showed that terrein inhibits MITF promoter activity in a dose-dependent manner. To elucidate the correlation between ERK pathway activation and a decreased MITF transcriptional level, PD98059, a specific inhibitor of the ERK pathway, was applied before terrain treatment and found to abrogate the terrein-induced MITF attenuation. Terrein also reduced the tyrosinase protein level for at least 72 h. These results suggest that terrain reduces melanin synthesis by reducing tyrosinase production via ERK activation, and that this is followed by MITF down-regulation.

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Evaluation of the Radioimmunotherapy Using I-131 labeled Vascular Endothelial Growth Factor Receptor2 Antibody in Melanoma Xenograft Murine Model (흑색종에서의 I-131표지 혈관내피세포성장인자 수용체2항체를 이용한 방사면역치료 평가)

  • Kim, Eun-Mi;Jeong, Hwan-Jeong;Park, Eun-Hye;Cheong, Su-Jin;Lee, Chang-Moon;Jang, Kyu-Yun;Kim, Dong-Wook;Lim, Seok-Tae;Sohn, Myung-Hee
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.4
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    • pp.307-313
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    • 2008
  • Purpose: Vascular endothelial growth factor (VEGF) and its receptor, fetal liver kinase 1 (Flk-1), play an important role in vascular permeability and tumor angiogenesis. The aim of this study is to evaluate the therapeutic efficacy of $^{131}I$ labeled anti-Flk-1 monoclonal antibody (DC101) on the growth of melanoma tumor, which is known to be very aggressive in vivo. Materials and Methods: Balb/c nude mice were injected subcutaneously with melanoma cells in the right flank. Tumors were allowed to grow up to $200-250\;mm^3$ in volume. Gamma camera imaging and biodistribution studies were performed to identify an uptake of $^{131}I$-DC101 in various organs. Mice with tumor were randomly divided into five groups (10 mice per group) and injected intravenously; control PBS (group 1), $^{131}I$-DC101 $50\;{\mu}g/mouse$ (group 2), non-labeled DC101 $50\;{\mu}g/mouse$ (group 3), $^{131}I$-DC101 $30\;{\mu}g/mouse$ (group 4) and $15\;{\mu}g/mouse$ (group 5) every 3 or 4 days for 20 days. Tumor volume was measured with caliper twice a week. Results: In gamma camera images, the uptake of $^{131}I$-DC101 into tumor and thyroid was increased with time. Biodistribution results showed that the radioactivity of blood and other major organ was gradually decreased with time whereas tumor uptake was increased up to 48 hr and then decreased. After 4th injection of $^{131}I$-DC101, tumor volume of group 2 and 4 was significantly smaller than that group 1. After 5th injection, the tumor volume of group 5 also significantly reduced. Conclusion: These results indicated that delivery of $^{131}I$ to tumor using FlK-1 antibody, DC101, effectively blocks tumor growth in aggressive melanoma xenograft model.

Studies on the ecological variations of rice plant under the different seasonal cultures -I. Variations of the various agronomic characteristics of rice plant under the different seasonal cultures- (재배시기 이동에 의한 수도의 생태변이에 관한 연구 -I. 재배시기 이동에 의한 수도의 실용제형질의 변이-)

  • Hyun-Ok Choi
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.3
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    • pp.1-40
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    • 1965
  • To measure variations in some of the important agronomic characteristics of rice varieties under shifting of seedling dates, this study has been carried out at the Paddy Crop Division of Crop Experiment Station(then Agricultural Experiment Station) in Suwon for the period of three years 1958 to 1960. The varieties used in this study were Kwansan, Suwon #82, Mojo, Paltal and Chokwang, which have the different agronomic characteristics such as earliness and plant type. Seeds of each variety were sown at 14 different dates in 10-day interval starting on March 2. The seedlings were grown on seed bed for 30, 40, 50, 60, 70 and 80 days, respectively. The results of this study are as follows: A. Heading dates. 1. As the seeding date was delayed, the heading dates was almost proportionally delayed. The degree of delay was higher in early varieties and lower in late varieties and the longer the seedling stage, the more delayed the heading date. 2. Number of days to heading was proportionally lessened as seeding was delayed in all the varieties but the magnitude varied depending upon variety. In other words, the required period for heading in case of late planting was much shortened in late variety compared with early one. Within a variety, the number of days to heading was less shortened as the seedling stage was prolonged. Early variety reached earlier than late variety to the marginal date for the maximum shortening of days to heading and the longer the seeding stage, the limitted date came earlier. There was a certain limit in seeding date for shortening of days to heading as seeding was delayed, and days to heading were rather prolonged due to cold weather when seeded later than that date. 3. In linear regression equation, Y=a+bx obtained from the seeding dates and the number of days to heading, the coefficient b(shortening rate of days to heading) was closely correlated with the average number of days to heading. That is, the period from seeding to heading was more shortened in late variety than early one as seeding was delayed. 4. To the extent that the seedling stage is not so long and there is a linear relationship between delay of seeding and shortening of days to heading, it might be possible to predict heading date of a rice variety to be sown any date by using the linear regression obtained from variation of heading dates under the various seeding dates of the same variety. 5. It was found out that there was a close correlation between the numbers of days to heading in ordinary culture and the other ones. When a rice variety was planted during the period from the late part of March to the middle of June and the seedling ages were within 30 to 50 days, it could be possible to estimate heading date of the variety under late or early culture with the related data of ordinary culture. B. Maturing date. 6. Within (he marginal date for maturation of rice variety, maturing date was proportionally delayed as heading was delayed. Of course, the degree of delay depended upon varieties and seedling ages. The average air temperature (Y) during the ripening period of rice variety was getting lower as the heading date. (X) was delayed. Though there was a difference among varieties, in general, a linear regression equation(y=25.53-0.182X) could be obtained as far as heading date were within August 1 to September 13. 7. Depending upon earliness of a rice variety, the average air temperature during the ripening period were greatly different. Early variety underwent under 28$^{\circ}C$ in maximum while late variety matured under as low as 22$^{\circ}C$. 8. There was a highly significant correlation between the average air temperature (X) during the ripening period, and number of day (Y) for the maturation. And the relationship could be expressed as y=82.30-1.55X. When the average air temperature during the period was within the range of 18$^{\circ}C$ to 28$^{\circ}C$, the ripening period was shortened by 1.55 days with increase of 1$^{\circ}C$. Considering varieties, Kwansan was the highest in shortening the maturing period by 2.24 days and Suwon #82 was the lowest showing 0.78 days. It is certain that ripening of rice variety is accelerated at Suwon as the average air temperature increases within the range of 18$^{\circ}C$ to 28$^{\circ}C$. 9. Between number of days to heading (X) related to seeding dates and the accumulated average air temperature (Y) during the ripening period, a positive correlation was obtained. However, there was a little difference in the accumulated average air temperature during the ripening period even seeding dates were shifted to a certain extent. C. Culm- and ear-lengths. 10. In general all the varieties didn't show much variation in their culm-lengths in case of relatively early seeding but they trended to decrease the lengths as seeding was delayed. The magnitude of decreasing varied from young seedlings to old ones. Young seedlings which were seeded during May 21 to June 10 didn't decrease their culm-lengths, while seedlings old as 80 days decreased the length though under ordinary culture. 11. Variation in ear-length of rice varieties show the same trend as the culm-length subjected to the different seeding dates. When rice seedlings aged from 30 to 40 days, the ear-length remained constant but rice plants older than 40 days obviously decreased their ear-lengths. D. Number of panicles per hill. 12. The number of panicles per hill decreased up to a certain dates as seeding was delayed and then again increased the panicles due to the development of numerous tillers at the upper internodes. The seeding date to reach to the least number of panicles of rice variety depended upon the seedling ages. Thirty- to 40-day seedlings which were seeded during May 31 to June 10 developed the lowest number of panicles and 70- to 80-day seedlings sown for the period from April 11 to April 21 reached already to the minimum number of panicles. E. Number of rachillae. 13. To a certain seeding date, the number of rachillae didn't show any variation due to delay of seeding but it decreased remarkably when seeded later than the marginal date. 14. Variation in number of rachillae depended upon seedling ages. For example, 30- to 40-day old seedlings which, were originally seeded after May 31 started to decrease the rachillae. On the other hand, 80-day old seedlings which, were seeded on May 1 showed a tendency to decrease rachillae and the rice plant sown on May 31 could develop narrowly 3 or 4 panicles. F. Defective grain and 1.000-grain weights. 15. Under delay of the seeding dates, weight of the defective grains gradually increased till a certain date and then suddenly increased. These relationships could be expressed with two different linear regressions. 16. If it was assumed that the marginal date for ripening was the cross point of these two lines, the date seemed. closely related with seedling ages. The date was June 10- in 30- to 40-day old seedlings but that of 70- to 80-day old seedlings was May 1. Accordingly, the marginal date for ripening was getting earlier as the seedling stage was prolonged. 17. The 1.000-grain weight in ordinary culture was the heaviest and it decreased in both early and late cultures. G. Straw and rough rice weights. 18. Regardless of earliness of variety, rice plants under early culture which were seeded before March 22 or April 1 did not show much variation in straw weight due to seedling ages but in ordinary culture it gradually decreased and the degree was became greater in late culture. 19. Relationship between seeding dates (X) and grain weight related to varieties and seedling ages, could be expressed as a parabola analogous to a line (Y=77.28-7.44X$_1$-1.00lX$_2$). That is, grain yield didn't vary in early culture but it started to decrease when seeded later than a certain date, as seeding was delayed. The variation was much greater in cases of late planting and prolongation of seedling age. 20. Generally speaking, the relationship between grain yield (Y) and number of days to heading (X) was described with linear regression. However, the early varieties were the highest yielders within the range of 60 to 110, days to heading but the late variety greatly decreased its yield since it grows normally only under late culture. The grain yield, on the whole, didn't increase as number of days to heading exceeded more than 140 days.

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