• Journal of Plant Biotechnology
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• v.29 no.3
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• pp.185-188
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• 2002

Off-white, friable embryogenic calluses were formed on the internal integument of mature seeds of yuzu (Citrus junos) cultured on Murashige and Skoog's basal medium at a frequency of 1.2%. Embryogenic calluses were proliferated when cultured on medium with 1 mg/L 2,4-D. Upon transfer to medium with 0.1 mg/L kinetin, embryogenic calluses produced numerous somatic embryos. Embryogenic suspension cultures were established by placing embryogenic calluses into liquid medium with 1 mg/L 2,4-D. When plated onto medium with 0.5 mg/L ABA, embryogenic cells developed into somatic embryos at a high frequency, and then regenerated into plantlets. Plantlets were successfully transplanted to potting soil and grown in a greenhouse.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.236-243
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• 2017

In the present study, 70% ethanol extract, the ethyl acetate fraction were prepared from citron (Citrus junos)seed and their antioxidative ability was evaluated. The yields of extract and fractions were 5.1 and 0.9% per dried powder, respectively. In the 1,1-Phenyl-2-picrylhydrazyl (DPPH) radical test, free radical scavenging activities ($FSC_{50}$) of 70 % ethanol extract, ethyl acetate fraction were 512.1 and $514.0{\mu}g/mL$, respectively. Evaluation of total antioxidant capacities ($OSC_{50}$) using $Fe^{3+}$-EDTA system. Their $OSC_{50}$ of ethyl acetate fraction were $86.5{\mu}g/mL$. this antioxidant capacities higher than that of 70% ethanol extract. but lower than that of L-ascorbic acid ($1.72{\mu}g/mL$), known as a prominent water soluble antioxidant. The cellular protective effects on the $^1O_2$-induced cellular damage of rabbit erythrocytes were evaluated and the results showed that the extract was lower than (+)-${\alpha}$-tocopherol and low concentration of ethyl acetate fraction was similar to (+)-${\alpha}$-tocopherol. but not at high concentrations of ethtyl acetate fraction. it was able to induce cellular damage at high concentration.

• Journal of Applied Biological Chemistry
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• v.50 no.3
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• pp.148-154
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• 2007

Volatile components of the essential oils of Satsuma mandarin (C. unshiu), Dangyuza (C. grandis), Yuza (C. junos), Byungkyul (C. playtymamma), Jinkyul (C. sunki), and Hakyul (C. natsudaidai) grown in Jeju Island were isolated from the fruit peels by hydro distillation and determined by GC-MS. GC-MS analysis identified 58 compounds, with main components being d-limonene $(64.01{\sim}79.34%),\;{\beta}-myrcene\;(3.01{\sim}26.53%),\;{\gamma}-terpinene\;(0.11{\sim}12.88%),\;{\beta}-pinene\;(0.78{\sim}4.74%),\;and\;{\alpha}-pinene\;(1.01{\sim}2.55%)$. Differences in compositions and contents of the essential oils were observed among citrus varieties. Effects of citrus oils on growth inhibitions of Escherchia coli, Staphyllococcus epidermidis, and Candida albicans were investigated using disc diffusion assay and minimal inhibitory concentration (MIC) assay. The essential oils inhibited growths of the test organisms, exhibiting higher levels of activity against Gram-positive S. epidermidis (MIC values $0.04{\sim}0.17mg/mL$), whereas Gram-negative E. coli was moderately resistant (MIC values $1.66{\sim}20.30mg/mL$). MIC of citrus essential oils ranged from $0.82{\sim}23.69mg/mL$ against C. albicans. The essential oils obtained from C. sunki, C. grandis, and C. playtymamma showed the highest antimicrobial activities against S. epidermidis and C. albicans, indicating their potential as natural antimicrobial agents.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.65-65
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• 2023

제주도에서 재배되어 온 재래귤 5종(당유자, 유자, 청견, 하귤, 팔삭) 부위별 에탄올 추출물의 총 폴리페놀 함량 측정, 총 플라보노이드 함량 측정, DPPH radical 소거 활성 실험을 실시하였다. 총 폴리페놀 함량의 경우, 5종 재래귤(당유자, 유자, 청견, 하귤, 팔삭) 부위별 에탄올 추출물 가운데 당유자의 외피(244.84mg/g)와 중피(200.70mg/g) 처리구에서 폴리페놀 함량이 가장 높았다. 총 플라보노이드 함량의 경우, 총 폴리페놀의 함량 측정에서와 마찬가지로 5종 재래귤(당유자, 유자, 청견, 하귤, 팔삭) 부위별 에탄올 추출물 가운데 당유자의 외피에서 102.12mg/g으로 가장 높았으며, 청견과 하귤, 팔삭의 플라보노이드 함량은 폴리페놀 처리구와 같이 당유자 처리구보다 적게 나타났다. DPPH radical 소거 활성의 경우, 총 폴리페놀 함량과 총 플라보노이드 함량 측정의 결과에 같은 경향으로 5종 재래귤(당유자, 유자, 청견, 하귤, 팔삭) 부위별 에탄올 추출물 가운데 당유자의 외피(79.39%)와 중피(70.73%)에서 가장 양호한 항산화 활성을 나타내었다. 이러한 결과들로부터 당유자의 두꺼운 과피 구조인 외피와 중피에 에센셜 성분인 limonene, myrcene, β-ocimenes 등과 같은 향기성분들의 영향으로 생각되어 앞으로 이에 대한 연구가 더 필요하리라 생각된다.

• Research in Plant Disease
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• v.25 no.4
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• pp.233-236
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• 2019

Citrus vein enation virus (CVEV), which was regulated as a quarantine virus in Korea, was firstly found on Jeju Island in 2017. In February 2018, a survey was carried out to determine the distribution of CVEV in the main commercial areas growing Citrus spp. and Poncirus trifoliata. The survey was performed at 203 groves in the southern Korean Peninsula and Jeju Island. CVEV infection was determined by reverse transcription polymerase chain reaction detection and sequencing. The coat protein (CP) gene sequences obtained from the CVEV-infected samples showed high similarities (more than 98%) to the previously reported CVEV CP sequences. In summary, CVEV was detected in 136 groves (67%), in which 85.4% of Citrus junos and 77.8% of Citrus unshiu were infected by CVEV. In Jeju Island, the infection rate of CVEV was relatively higher (90.6%). Our result revealed that CVEV has spread widely in Citrus and Poncirus in Korea. Based on the result, the Korean quarantine agency decide to exclude CVEV from quarantine in Korea.

• Korean journal of applied entomology
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• v.39 no.1
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• pp.13-19
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• 2000

This studies was carried out to investigate the natural enemies of citrus red mite, pononychus citri and seasonal occurrence of its major beneficial insects in Yuzu groves (Chonnam province) from 1996 to 1998. Natural enemies against citrus red mite were 9 species including Oligota kashmirica benifica, 0. yasumatsui, Stethorus punctillum, Chrysopa pallens, Propylea japonica, Orius sauteri, Scolothrips takahashii, Amblyseius womersleyi and one unidentified species of thrips (Family: Phlaeothripidae). Among them, Oligota kashmirica benzficu and Stethorus punctillum were found to be dominant species. 0 . kushmirica henifica had 4-5 generations from middle May to middle November with peak in early September. S. punctillum had 3 generations from late May to late October with peak of late June to middle July. Population dynamics between predator ( 0 . kushmiricu benifica and S. punctillum) and prey (Panonychus citri) were quite well synchronized until September but predator density was decreased abruptly after October.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.45-50
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• 2005

Virus-free stocks was produced by the combination of the heat treatment of virus infected plant and shoot-tip grafting (STS). To produce virus-free stocks, the plants infected with citrus viruses were used for virus-free stock production using the modified method of STG in thermotherapy at $40^{\circ}C$ for 16 hours in the light, and at $30^{\circ}C$ for 8 hours of darkness for 4 weeks. Trifoliate orange (P. trifoliata) were used as rootstock seedling for STG. Percentages of virus-free stocks against citrus tristeza virus (CTV), satsuma dwarf virus (SDV) and citrus tatter leaf virus (CTLV) were $75.7\%,\;100.0,\%\;82.6\%$ respectively. Shoot tip size for successful STG were as small as possible. Less than $0.3\;\cal{mm}$ of shoot tips gave the hight efficiency of virus free plants but survival rates were low. And, survival rate after shoot-tip culture was analyzed and the rates were dependant on the cultivars; Yuzu cultivar showed the hight survival rate ($74.6\%$) and early satsuma mandarin (Iwasagi) was $13.3\%$ as the lowest cultivar. But citrus trees were not succeed to grown, turned brown, and died.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.27-32
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• 2001

Methanol extracts from 43 materials of 17 fruit trees were tested for their insecticidal activities toward five agricultural and four stored-product anthropod pests. Efficacy varied with insect species, plant species, and tissue sampled. At a concentration of 2,500 ppm, strong activity was observed with extracts of Chaenomeles sinensis and Punica granatum seeds against Myzus persicae adult females, Vitis vinifera seeds against Nilaparvata lugens adults, Citrus junos, Citrus paradisi, Cucumis melo Linne var. reticulatus, Diospyros kaki, Malus pumila var. dulcissima, Prunug persica, and V. vinifera seeds against Plutella xylostella, Citrus sinensis seeds against Spedoptera litura larvae, and Ch. sinensis and V. vinifera against Tetranychus urticae adults. Against four stored-product insect pests at 50 ppm, seed extracts of Ch. sinensis and V. vinifera against Sitophilus oryzae adults, and Ch. sinensis, C. junos, D. kaki, and V. vinifera against Callosobruchus chinensis adults gave over 80% mortality. Extracts of all samples exhibited little and no activity against Lasioderma serricorne adults and Plodia interpunctella larvae.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.294-300
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• 2006

This study was carried out to evaluate the possibility of citron seed as industrial resource by analyzing chemical properties and the antioxidant activity. Crude lipid content of citron seed was $35.29{\pm}0.18%$. Total mineral content in citron seed was 1171.64 mg/100g and the potassium content ($637.99{\pm}5.38mg/100g$) was the highest. The contents of total phenols and flavonoids in citrus seed were $24.44{\pm}1.10mg/100g$ and $2.27{\pm}0.18mg/100g$, respectively. The electron donating ability using DPPH, hydroxy radical scavenging activity and SOD-like activity were increased significantly by increased the sample concentration in the reaction mixture. The nitrite scavenging ability was dependent on pH of reaction mixture and sample concentration. It was higher activity at pH 1.2 than pH 4.2. During the storage of soybean oil, the peroxide and acid values of the oil were significantly increased regardless of addition of citron extract. But antioxidant activity of soybean oil added with ethanol extract from citron seed was superior to that of control (sample with no addition) at 16 days of storage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.224-231
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• 2009

Volatile components in Olive Flounder fed diets containing 0, 2,5, 5.0, and 7.5% yuza (Citrus junas Sieb ex Tanaka) for 4 months were investigated. Samples were extracted by solid-phase micro extraction and analyzed by gas chromatography/mass spectrometry. Among 89 compounds detected, 82 were positively identified. Volatile compounds of Olive Flounder fed the unsupplemented diet comprised 12 acids, 10 alcohols, eight aldehydes, five aromatic compounds, nine esters, 12 hydrocarbons, four ketones, two monoterpenes, and one miscellaneous compound. Compounds identified in Olive Flounder fed the yuza-supplemented diets consisted of 10 esters, 11 monoterpenes, 13 sesquiterpenes, and two miscellaneous compounds, with the other compounds being the same as in the control. The most abundant class of compounds in flounders fed the yuza-supplemented diet was the monoterpenes, which included limonene, $\beta$-terpinene, $\beta$-trans-ocimene, and $\alpha$-terpinolene. Of the 13 sesquiterpenes identified in flounder fed the yuza-supplemented diet, bicyclogermacrene was the major volatile compound followed by allo-aromadendrene, trans-caryophyllene, and $\delta$-cadinene. Bicyclogermacrene and germacrene D content increased significantly as the yuza supplementation increased.