• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.4
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• pp.235-241
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• 2004

There is a growing concern about the possible increase in inter-annual variation of minimum temperature during the winter season in Korea. This view is strengthened by frequently reported freezing injury to dormant fruit trees, while warmer winters have prevailed recently. The January minimum temperature record at fourteen weather stations was analyzed for 1951-2000. The results showed no evidence of increasing standard deviation at 3 locations between 1951-1980 and 1971-2000, while the remaining 11 stations showed a trend of decreasing standard deviation for the two periods. An empirical model explaining the spatial variation of the standard deviation was derived by regression analysis of 56 stations' data for 1971-2000. Daily minimum temperature and the site elevation may account for 68% of the observed variations. We applied this model to restore the average standard deviation of the January minimum temperature for 1971-2000, and the result was used to produce gridded minimum temperature data for the recurrence interval of 10 and 30 years at 250m resolution. A digital form of the plant hardiness zone map may be developed from this product for site-specific selection of adapted plant species.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.199-205
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• 2022

BACKGROUND: The freezing injury by pruning can be reduced by suspending pruning work when severe cold weather (-23 to -49℃) is forecast. Minimum air temperature of the study area, Gunwi region at February 3, 2012 was -21.9℃, and the subzero temperature continued until April 8, 2012. This study was conducted in two years to investigate the effect of delaying winter pruning until full bloom on shoot growth and fruit quality of 'Fuji'/M.9 apple trees. METHODS AND RESULTS: The time of pruning were March 26 for dormant, April 3 for bud break, and May 2 for full bloom. The winter pruning at full bloom significantly reduced fruit weight for two years compared with the control (winter pruning at dormant), and shoot growth was reduced only in the following year. There was no significant effect of delaying winter pruning at bud break on soluble solid content, fruit red color, return bloom, and pruning weight for two years compared with the control. CONCLUSION(S): These results indicated the delaying winter pruning at bud break of 'Fuji'/M.9 apple tree did not offer any disadvantage over comparable dormant pruning, since the fruit quality was not affected. The delayed pruning at full bloom resulted in decreased fruit weight, though shoot growth, fruit quality, and return bloom were not affected by the delayed pruning. So, the delayed pruning should be considered carefully only for the fruit tree orchards in diseases.

• Food Science and Preservation
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• v.15 no.5
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• pp.635-641
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• 2008

This study was conducted to investigate the optimal sub-zero temperature for storage of two garlic cultivars, the northern ecotype 'Jaerae' and the southern ecotype 'Daeseo'. These cultivars of garlic bulbs were stored at different temperature (room temperature, $0^{\circ}C$, and $-4^{\circ}C$) conditions after predrying. Southern ecotype garlic showed higher weight loss than northern ecotype garlic. Northern ecotype garlic at $-4^{\circ}C$ exhibited less than 5% of weight loss during 10 month storage. Sprouting rate was higher in southern than in northern ecotype at room temperature storage. The value of injury by disease and insect was similar between southern ecotype and northern ecotype for 5 month storage, and then northern ecotype showed higher value of injury by disease and insect than southern ecotype. Hunter 'b' value of northern ecotype garlic was the lowest at $-4^{\circ}C$ storage. Northern ecotype garlic showed no cold injury at freezing point temperature storage. However, southern ecotype garlic had $0{\sim}5.3%$ cold injury occurrence at $-4^{\circ}C$ storage. Respiration and ethylene production exhibited the highest at room temperature storage, those had the slight increase at $0^{\circ}C$ and $-4^{\circ}C$ storages. Northern ecotype showed higher enzymatic pyruvic acid and fructan contents than those of southern ecotype. Enzymatic pyruvic acid content increased and fructan contents decreased during storage time.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.406-410
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• 2005

This study was conducted to establish the efficient protocols of the germination and cryopreservation of dehisced Korean ginseng seeds for long-term germ­plasm conservation. $GA_3$ and BA treated on seed for 24 hr facilitated germination at 5 and $10^{\circ}C$. Germination percentage of desiccated seeds was decreased under moisture content (MC) of below $7.2\%$. Dehisced ginseng seeds were dried under airflow of laminar floor cabinet and seed drying room. The high levels (more than $90\%$) of germination after cryogenic exposure were obtained after drying under vertical airflow of laminar floor for 12-30 hours (MC $10.6{\~}7.2\%$). Decrease in germination percentage of ginseng seeds due to desiccation damage and freezing injury was observed at MC of below $7.2\%$ and of above $12.1\%$, respectively. Therefore, MC of ginseng seeds need to be controlled with a range of $8{\~}10\%$ to avoid damages from both desiccation and freezing.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.21 no.2
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• pp.73-78
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• 2015

Persimmons on the trees are often exposed to weather condition of cold temperature before harvest, which affects the fruit quality at harvest time and later storage. This study investigated the effect of the harvest season temperature on the storage quality of 'Fuyu' sweet persimmons. Monitoring the temperature changes in the orchard showed five times of cold temperature below the freezing temperature of persimmon, $-2.1^{\circ}C$, in the harvesting period between mid October and mid November with the lowest being as low as $-5.4^{\circ}C$. Among three different harvestings, the tertiary one at mid November showed decreased 'L' value and consistently high 'a' value of color index and high reduction in hardness during 150 days storage of fruits at $0^{\circ}C$ showing freeze-injured symptoms, compared to the first one at mid October and the second one at early November. The fruits of first harvest maintained consistently hard texture with increased 'a' color value probably due to postharvest ripening. The tertiary harvest exhibited increase in fructose and glucose contents and decrease in sucrose of the fruits, being very different from the first and secondary harvests which maintained constant level of all three free sugars. Mid November with possible sudden temperature drop is unsuitable period for harvesting sweet persimmons in the quality at harvest and later storage, and thus the harvest should be designed to be done before that time.

• Asian Journal of Turfgrass Science
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• v.16 no.2
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• pp.65-73
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• 2002

Studies were conducted to determine the effect of undersoil heating on growth and quality of turfgrasses including Kentucky bluegrass (Poa pratensis L.‘Nuglade’), perennial ryegrass (Lolium perenne L.‘Accent’), tall fescue (Festuca arundinacea Schreb.‘Pixie’), and Korean lawngrass (Zoysia japonica Steud.) in simulated athletic field during winter season in Korea. Mineral contents in clippings of turfgrasses grown at different soil mixtures and temperatures were also analyzed. Undersoil heating (approximately 20$\pm$2$^{\circ}C$) was effective in protecting turfgrasses except Korean lawngrass from freezing injury and discoloration of shoots due to extremely cold temperatures during midwinter. Among turfgrasses grown at undersoil heating zone, tall fescue and perennial ryegrass showed the highest clipping weights and chlorophyll contents, respectively. However, anthocyanin contents of shoots were higher in Kentucky bluegrass. There was little or no difference in clipping weights, chlorophyll contents, anthocyanin contents and greenness of shoots between turfgrasses grown at two soil mixtures composed of 80% sand＋10% peat moss＋10% soil (v/v/v) and 80% sand＋20% pea moss (v/v). Contents of mineral K, Ca and Mg in clippings of cool-season turfgrasses were comparatively higher in a soil mixture composed of 80% sand＋10% peat moss＋10% soil, but little difference in contents of N and P was observed between two soil treatments. Results indicated that undersoil heating can improve quality of turf surface by thawing soil, melting snow, and maintaining shoot growth and greenness of turfgrasses in sports field during winter season.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6697-6701
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• 2013

Objective: To explore the inhibiting effect and mechanism of Endostar injection concomitant with cryoablation on lung adenocarcinoma A549 xenografts in nude mice. Materials and Methods: A total of 24 nude mice with subcutaneous xenografts of the A549 cell line were established and divided into 4 groups when the maximal diameters of tumors became 1 cm: control group, Endostar group, cryoablation group and combination group (Endostar concomitant with cryoablation). The nude mice were sacrificed after 21-days treatment, tumour tissues were removed to measure their volume, in situ test of TdT-mediated dUTP nick end labeling (TUNEL) was adopted to determine the cellular apoptosis around freezing injury zones, and immunohistochemical SP test was applied for the detection of micro-vessel density (MVD) and vascular endothelial growth factor (VEGF) expression levels. Results: At 21-days after treatment, the growth velocities of control group, Endostar group, cryoablation group and combination group were $236.7{\pm}51.2%$, $220.0{\pm}30.6%$, $159.5{\pm}29.3%$ and $103.3{\pm}25.5%$ (P<0.01), while cellular apoptosis rates of tumors were $21.7{\pm}2.34%$, ($22.17{\pm}1.47$)%, $38.3{\pm}1.37%$ and $49.2{\pm}1.72%$, (P<0.01), respectively, according to the immunohistochemical test. MVD and VEGF expression levels in the combination group were both lower than in other groups (P<0.01), also being positively related (r=0.925, P<0.01). Conclusions: Endostar can significantly improve the inhibitory effects of cryoablation on xenografts of lung adenocarcinoma A549, and the mechanism is probably associated with its function as an inhibitor of tumour neo-angiogenesis through down-regulating VEGF expression.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.43-58
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• 2015

This study is conducted in order to select the varieties that can supplement problems related with organic cultivation of bulb onion (Allium cepa L.). 15 test varieties were selected considering rural preference, breeding line, breeding company, open-pollinated cultivar, F1 hybrid cultivar of either domestic or foreign products. Onion varieties were assessed in 5 criteria which are : growth of plants in low temperature, freezing injury resistance, resistance to physiological disorder such as bolting and doubled bulb, lodging index during harvest, and marketable yield. As a result, e-Joeun, Katamaru, Pop, Art, Singihan among F1 hybrid cultivars and Changnyeongdaego, Seouldaego, and Chunjujunggo among open-pollinated cultivars were selected as more suitable varieties for the organic cultivation. Although Sunpower cannot be selected in varieties those are suitable for organic cultivation, it showed excellent traits in the bulb characteristics. No significant differences were found between open-pollinated cultivar and F1 hybrid cultivar except growth of plants in low temperature (plant sheath diameter) and lodging index during harvest (May 24th). And no significant differences were recognized between domestic varieties and foreign varieties except missing plant ratio after wintering.

• Research in Plant Disease
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• v.22 no.3
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• pp.198-201
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• 2016

Recently, severe dieback of apple tree has occurred in the apple orchards of Chungbuk province. Dieback rate and its casual agents have been investigated on the Chungbuk province apple orchards in 2013-2015. Out of 29,265 apple trees in the 27 orchards throughout Chungbuk province, 4,000 apple trees (13.7%) showed dieback symptoms. The causes of dieback were Phytophthora rot (50.4%), violet root rot by Helicobasidium sp. (27.1%), rodents (10%), white root rot by Rosellinia sp. (6.3%), and freezing injury (6.3%). Compared to previous reports published in 1995 and 2006, Phytophthora rot was the most dominant disease, which is thought to be due to high temperature during growing season and the increase of lowland cultivation. Results of this study will be useful to establish of the management strategy of apple tree dieback that has been increased recently.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.522-527
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• 2010

Onion has been reported to contain various organosulfur compounds which have antibiotic and anticarcinogenic properties and flavonoid like quercetin which is a valuable natural source of antioxidants. Carbohydrates in onion constitute about 80% of dry matter, and the major non-structural carbohydrate of onion bulb is fructo-oligosaccharides, well known as fructan, followed by glucose, fructose, and sucrose. The sugar concentration is associated with dormancy and storage life of onion, occurring as decrease in glucose, fructose and fructan, particularly towards the end of storage. Forced air pre-drying for 15-20 days at room temperature is an essential procedure to reduce freezing injury and sprouting, then onion bulbs can be stored at $0^{\circ}C$ for 6 months to control sprouting and decay. Bacterial soft rot caused by $Erwinia$ and $Pseudomonas$ is the main postharvest disease when the bulbs are infected with the bacteria and stored at room temperature. Browning in sliced onion is due to oxidation of phenolic compounds by polyphenol oxidase and it can be inhibited by citric acid treatment, packing with nitrogen gas, and polyethylene film.