• Applied Biological Chemistry
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• v.37 no.3
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• pp.182-188
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• 1994

Similar to the $^{42}K$ uptake, $^{86}Rb$ uptake by the roots of Hordeum distichum grown in the hydroponic culture was negatively correlated with the concentration of K supplied previously, showing that $^{86}Rb$ can be used for the K-bioassay. $^{86}Rb$ having longer half life (18.86 day) than $^{42}K$ (12.36 hr) allowed the use of larger number of root samples. $^{86}Rb$ uptake of 3 years old Citrus unshiu Marc. grown in water culture decreased drastically with the increase of K concentration of the culture solution, thus demonstrating that the nutrition status of K for citrus trees can be diagnosed by K-bioassay using $^{86}Rb$ tracer. $^{86}Rb$ uptake by the excised roots of Hordeum distichum grown in the pot with different K fertilizations was well correlated with the exchangeable K in soil. The amount of exchangeable K in soil for the optimal plant growth can be determined by its relationship. $^{42}K$ and $^{86}Rb-uptake$ by the Hordeum distichum roots were markedly inhibited by $5{\times}10^{-3}\; M$ KCN in the bioassay solution, indicating that uptake is energy-dependent. There was no significant relationship between K content in citrus leaves and K concentration in the water-culture medium. It is concluded that K-bioassay is a potentially useful tool for determining of K requirement in citrus trees.

• Nuclear Engineering and Technology
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• v.8 no.3
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• pp.139-143
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• 1976

$^{32}$ P was supplied to the roots of stem-ringed 1-year-old apple trees and 2-year-old citrus trees on which bark segments were isolated above and below the ring. $^{32}$ P was translocated to shoots and leaves although considerable translocation occurred especially in wood and bark tissues. The accumulation of $^{32}$ P in isolated bark segments indicated that the occurrence of these materials in this tissue was via radial translocation from xylem tissue, and that the main upward translocation pathway of $^{32}$ P supplied to roots is through the xylem.

• Horticultural Science & Technology
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• v.16 no.4
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• pp.514-516
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• 1998

This study was conducted to observe the effects of urea foliar spray to replace soil fertilization on defoliation ratio, shoot growth and fruit setting in satsuma mandarin (Citrus unshiu Marc.). Twice foliar sprays of 1% urea after harvest increased N and chlorophyll contents in leaves, and decreased defoliation during the winter season. The growth of the ovary and spring shoot was stimulated by the twice 0.8% urea foliar spray around the time of bud emergence. In addition, the treatments increased the number of flowers and fruit setting, but didn't influence fruit quality.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.68.2-69
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• 2003

Genetic transformation carried out to induce the pathogenicity mutants from the two isolates, Elsinoe fawcettii R-34 and MUD of citrus scab fungus to hygromycin resistant by transferring plasmides (pUCATPH) that contain hygB gene. We produced protoplast for transformation by using of combinations of available enzymes including ${\beta}$-D-glucanase, ${\beta}$ -glucuronidase, Iyticase and driselase. The protoplasts regenerated at 64 $\mu\textrm{g}$/ml of hygromycin B but not 128 $\mu\textrm{g}$ in sensitivity test to identify the concentration of useful marker for the selection of transformants. Approximately 1200 and 67 hygromycin resistant isolates from strain R-34 and strain MUD, respectively, were isolated on PDA added with 200 $\mu\textrm{g}$ /ml of hygromycun B. Fifty seven and 4 of hygromycin resistant isolates from strain R-34 and MUD, respectively, did not produce necrotic lesions on the leaf in detached-leaf assay. Finally, 9 isolates were isolated from strain R-34, and these Isolates produced non or very few symptoms on seedlings of citrus in greenhouse pathogenicity test. And it's very interesting that some isolates produced melanose-like symptom on very young leaves which it was not typical symptom and somtimes produced on only expanded leaf.

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.343-347
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• 2013

BACKGROUND: Control of alternate bearing satsuma mandarin in Jeju is very important to maintain the optimum price of fruit and get the sustainable income of farmers. Unlike orange, Satsuma mandarin is well known to sensitive on alternate bearing. We carried out the experiment to know the effect of foliar application of $GA_3$ on the flowering and fruit quality of satsuma mandarin (C. unshiu Marc. cv. Miyagawa). METHODS AND RESULTS: To experiment, the treatments consist of control, different concentration of $GA_3$ (25, 50 and 100 mg/L), machine oil emulsion 100 times and mixture of various concentration of $GA_3$ (25 and 50 mg/L) with machine oil emulsion 100 times which it was applied on 15 year-old Miyagawa satsuma mandarin at December 29, 2011. Foliar application of $GA_3$ in winter reduced the flowering of satsuma mandarin. Flower-leaf ratio was significantly reduced at 100 mg/L $GA_3$, while no differences observed in low concentration of $GA_3$ (25 and 50 mg/L). However, it was significantly decreased to 0.19 in application of $GA_3$ 25 and 50 mg/L with machine oil emulsion 100 times mixture. Number of leaves per fruit was significantly increased as foliar application of $GA_3$ also it reduced the fruits remarkably. Soluble solid contents and Hunter's a of peel color ratio showed no difference among $GA_3$ single treatments, but it was reduced in $GA_3$ 25 and 50 mg/L with machine oil emulsion 100 times mixtures significantly. From the results, it has been found that higher $GA_3$ concentration can reduce the number of flowers on the alternate bearing of satsuma mandarin. However, it was found that lower concentration of $GA_3$ with machine oil emulsion mixture 100 times can reduce flowering. CONCLUSION(S): The foliar application of $GA_3$ (100 mg/L) can alleviate alternate beraring. Also, mixture of lower concentration of $GA_3$ with machine oil emulsion 100 times can retard flowering more significantly while it needs further confirmation.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.480-485
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• 2014

In satsuma mandarin (C. unshiu Marc. cv. Miyagawa), alternate bearing is frequently occurred. It is very difficult to control and maintain the optimum production because satsuma mandarin is a very sensitive citrus cultivar. We carried out the experiment to find out the effects of foliar application of gibberellic acid ($GA_3$) and machine oil emulsion mixture on flowering and fruit quality of satsuma mandarin grown on open field. The treatments were composed of control (no application), $GA_3$ (25, 50 and $100mg{\cdot}L^{-1}$), machine oil emulsion 100 times and mixture of $GA_3$ (25 and $50mg{\cdot}L^{-1}$) with machine oil emulsion 100 times on 16 year-old 'Miyagawa' satsuma mandarin on December 30, 2012. Foliar application of $GA_3$ during winter season led to a reduction of the flowering in the following year. $GA_3$ decreased flowering in dose dependant manner. However, application of $GA_3$ and machine oil emulsion (100 times-diluted mixture) inhibited effectively the flowering compared to $GA_3$ only. Also, flower-leaf ratio was significantly decreased by the application of $GA_3$ 25 (0.54) and $50(0.41)mg{\cdot}L^{-1}$ with machine oil emulsion mixture in comparison to $GA_3$ 25 (0.86) and $50(0.60)mg{\cdot}L^{-1}$ only. The number of leaves per fruit increased in application of $GA_3$ and machine oil emulsion mixture as concentration of $GA_3$ increased. Fruit weight and sugar-acid ratio also increased in comparison to the control whereas fruit size, soluble solid content and acidity remained unchanged. From the results, it was suggested that $GA_3$ application can reduce the number of flowers on the alternate bearing of satsuma mandarin. Moreover, application of $GA_3$ (25 and $50mg{\cdot}L^{-1}$) with machine oil emulsion 100 times mixture can reduce the flowering effectively without altering fruit maturity and soluble solid contents. Therefore, it can be concluded that the application of $GA_3$ 25 and $50mg{\cdot}L^{-1}$ with machine oil emulsion 100 times might be useful in controlling alternate bearing in satsuma mandarin.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.441-447
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• 2021

It were investigated changes in internal and external temperature, relative humidity using tyvek, weedstop, and 35% shading net as covering material to reduce the freezing damage of 'Shiranui' hybrid mandarin grown in open field. It were also evaluated canopy covering effect and LT₅₀ of leaves by covering material when it was cold at -2℃. In tyvek, temperature difference between inside and outside was low at the height of 1.5m and was high at 0.4m. The relative humidity differed greatly between day and night, and was high at 6-8 a.m. At -2℃, Sum of temperature at the height of 1.5m of canopy for 24-hour after covering were at 3.4℃ higher in tyvek than in control. The LT₅₀ of leaves was at 1.51℃ in tyvek, 1.33℃ in withstop, and 1.61℃ in 35% shading net lower than in control. Considering thermal insulation and relative humidity in canopy, tyvek is expected to reduce low temperature damage when covering after making a fine hole for ventilation.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.10
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• pp.1461-1468
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• 2014

This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime) fruits and its leaves, Sesbania grandiflora L. (Agati sesbania) leaves, Piper sarmentosum Roxb (Wild betal) leaves, Curcuma domestica Valeton (Turmeric) roots, Morinda citrifolia L. (Beach mulberry) leaves, Cassia siamea britt (Siamea cassia) leaves, and Cocos nucifera L. (Coconut) peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC) were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, $135{\mu}g/mL$. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of $306{\mu}g/mL$ and $183{\mu}g/mL$, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% ($EC_{50}$) values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and $47.8{\mu}g/mL$, respectively. Flavonoid content of methanol extracts in S. grandiflora L. T was $22.5{\mu}g/mL$ and the highest among plant extracts tested. These results indicated that C. aurantifolia Swingle, S. grandiflora L., P. sarmentosum Roxb, and C. domestica Valeton have antibacterial and antioxidant activities and can be used as alternative antibiotics or potential feed additives for the control of animal pathogenic bacteria.

• Research in Plant Disease
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• v.19 no.2
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• pp.102-107
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• 2013

The percent of diseased fruit by Diaporthe citri was the most 16.8% in 2010 and the least 3.8% in 2005, and the average was 8.8% from 2003 to 2012. The degrees of disease incidence were relatively high, 17.0, 22.6, 19.2 and 18.9%, in 2003, 2004, 2007 and 2010, respectively. The percent of diseased fruit by Elsinoe fawcettii was the most 0.72% in 2004, and then gradually decreased to 0.08% in 2008, and the average was from 0.28% from 2004 to 2011. In case of canker by Xanthomonas citri subsp. citri, the percent of diseased fruit was the most 2.19% in 2004, and gradually decreased to 0.08 and 0.10% in 2009 and 2010, respectively. The average was 0.81% from 2004 to 2012. The melanose by D. citri was most in south-east area of Jeju Island, and east and west in case of canker. The melanose symptoms were initially appeared from mid June, mainly peaked late of July to late August. The canker symptoms were initially produced on leaves of natsudaidai and grapefruit cultivated in open field middle of June in 2010 and 2011 and late of May in 2012. The scab disease was firstly appeared approx. early or mid May and then rapidly increased late of May to middle of June. The inoculum was mainly produced from dead twigs late June to early of August.

• Korean Journal of Plant Tissue Culture
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• v.21 no.3
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• pp.145-150
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• 1994

This study was conducted to determine the effects of 3 cytokinins (BA,2iP and kinetin) and their concentrations (0, 0.1, 0.5, 1.0, and 2.0 mg/L) on multiple shoot production of Citrus spp. 'Sambokam' and 'Byungkyool' by nodal culture. Nodal explants were obtained from in vitro germinated seedlings of both cultivars. 'Sambokam' produced more multiple shoots than did 'Byungkyool' by nodal culture. Among the 3 cytokinins tested in this study BA supplemented in semi-solid MS basal medium was the most effective stimulator for multiple shoot production, and an optimal concentration was determined to be 1.0 mg/L. Shoot elongation and root formation were inhibited by increasing cytokinin concentration, regardless of cytokinin types. BA at 1.0 mg/L produced the most multiple shoots and the highest number of leaves in 'Sambokam', whereas any cytokinin and concentration studied in this experiment did not affect any scored variables such as shoot and leaf numbers, etc. in 'Byungkyool'.