• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.3
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• pp.288-298
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• 1992

Since the major important factors limiting plant growth and crop productivity are environmental stresses, of which low temperature is the most serious. It has been well known that many physiological processes are alterant in response to the environmental stress. With regard to the relationship between plant hormones and the regulation of chilling tolerance in rice seedlings, the major physiological roles of plant hormones: abscisic acid, ethylene and polyamines are evaluated and discussed in this paper. Rice seedlings were grown in culture solution to examine the effect of such plant hormones on physiological characters related to chilling tolerance and also to compare the different responses among tested cultivars. Intact seedlings about 14 day-old were chilled at conditions of 5$^{\circ}C$ and 80% relative humidity for various period. Cis-(＋)-ABA content was measured by the indirect ELISA technique. Polyamine content and ethylene production in leaves were determined by means of HPLC and GC respectively. Chilling damage of seedlings was evaluated by electrolyte leakage, TTC viability assay or servival test. Our experiment results described here demonstrated the physiological functions of ABA, ethylene, and polyamines related to the regulation of chilling tolerance in rice seedlings. Levels of cis-(＋)-ABA in leaves or xylem sap of rice seedlings increased rapidly in response to 5$^{\circ}C$ treatment. The tolerant cultivars had significant higher level of endogenous ABA than the sensitive ones. The ($\pm$)-ABA pretreatment for 48 h increased the chilling tolerance of the sensitive indica cultivar. One possible function of abscisic acid is the adjustment of plants to avoid chilling-induced water stress. Accumulation of proline and other compatible solutes is assumed to be another factor in the prevention of chilling injuies by abscisic acid. In addition, the expression of ABA-responsive gene is reported in some plants and may be involving in the acclimation to low temperature. Ethylene and its immediate precusor, 1-amincyclopropane-1-carboxylic acid(ACC) increased significantly after 5$^{\circ}C$ treatment. The activity of ACC synthase which converts S-adenosylmethionine (SAM) to ACC enhanced earlier than the increase of ethylene and ACC. Low temperature increased ACC synthase activity, whereas prolonged chilling treatment damaged the conversion of ACC to ethylene. It was shown that application of Ethphon was beneficial to recovering from chilling injury in rice seedlings. However, the physiological functions of chilling-induced ethylene are still unclear. Polyamines are thought to be a potential plant hormone and may be involving in the regulation of chilling response. Results indicated that chilling treatment induced a remarkable increase of polyamines, especially putrescine content in rice seedlings. The relative higher putrescine content was found in chilling-tolerant cultivar and the maximal level of enhanced putrescine in shoot of chilling cultivar(TNG. 67) was about 8 folds of controls at two days after chilling. The accumulation of polyamines may protect membrane structure or buffer ionic imbalance from chilling damage. Stress physiology is a rapidly expanding field. Plant growth regulators that improve tolerance to low temperature may affect stress protein production. The molecular or gene approaches will help us to elucidate the functions of plant hormones related to the regulation of chilling tolerance in plants in the near future.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.390-395
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• 2006

Effects of exogenously foliar applied glycine betaine (GB) on the growth and contents of osmolyte in tomato seedling was investigated. Plants treated with exogenous glycine betaine induced better biomass production and plant height during chilling stress than the untreated plants. The total soluble sugar contents in GB foliar-applied plants lower than that of untreated plants 28 days after foliar application. Total water soluble protein contents in GB foliar-applied plants did not change 28 days after chilling stress. In untreated plant, it decreased rapidly in the beginning of chilling stress. Proline contents in untreated plants rapidly increased by the beginning of chilling stress, and then slightly decreased during the next 3 weeks. However proline contents in GB foliar-applied plants did not change during the 28 days chilling stress period. The results suggest that foliar application of GB is a effect methods to increase the chilling tolerance of tomato seedlings in protected cultivation system at low temperature season.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.4
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• pp.384-391
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• 1997

In the cultivation of Bupleurum falcatum, one of the problems to surmount is long-term germination period and unstable germination. This experiment was done to examine the effect of $GA_3$ concentration [0(water), 0.01, 0.lmM], chilling, their treatment period [2, 4, 8 days ($GA_3$) : 0, 2, 4 weeks (chilling)] and light quality (red, white, dark) given during the period as pretreatment before sowing on the seed germination of its two cultivars (cv. Jaerae, cv. Jangsu). Light treatment was given during all the periods of $GA_3$ treatment or for 0, 2, 4 days at the end of the chilling treatment. There was no difference in the mean germination rate between the levels of all the treatments except the $GA_3$ concentration meaning that water imbibition and $GA_3$ treatment had the same effect. As light quality treatment during the water imbibition was forced, the mean germination rate of Jaerae, 2 to 4 days imbibition period or red light was more increased or accelerated compared to the other levels of the same treatment, respectively. The rate of Jaerae not affected by the light quality was the greatest in the 2 days water imbibition while the rate of Jangsu was the greatest when water-imbibed for 4 days or treated by red light. No chilling before sowing showed the highest rate due to the light quality and white light forced after sowing had greater rate than the dark treatment. Although there was no difference between the rates of light quality treatment levels in the condition of no chilling before sowing and white light treatment after sowing, the rate of Jangsu was enhanced or accelerated only under illumination during 2 days water imbibition before sowing.

• Journal of Life Science
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• v.12 no.6
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• pp.694-699
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• 2002

The present experiment was carried out to determine the effect of seed-coat softening by various chemicals, washing, chilling, and light treatment alone and in combination during desiccation of seeds on germination of gourd (Lagenaria siceraria Standl.) seeds. Potassium hydroxide, sodium hydroxide, acetone, acetonitrile, and acetamide were used as chemicals for the softening. Washing, prechilling, drying and light treatment of the softened seeds were done for a hour with tap water, for one or three weeks at 3$^{\circ}C$, 12 hr at 35$^{\circ}C$, and 14 hr a day at 3$0^{\circ}C$ with red light illumination or darkness, respectively. FR-yongjadaemok and FR-kunghap were used as test cultivars. Seed-coat softening with 10% acetone and acetonitrile for 1 hour enhanced and accelerated seed germination compared to the other chemicals and water imbibition. KOH treated for the softening was necessary to increase the germination rate of seeds for following chilling, but acetone did not influence their germinability regardless of chilling. Washing the softened seeds in tap water increased the germination rate in comparison with no-washing. During desiccation of the seeds sequentially treated with the softening, washing and chilling, red light treatment showed higher germination rate than dark one, suggesting that red light treatment are necessary during desiccation.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.582-593
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• 2022

Among abiotic stresses in plants, drought and chilling stresses reduce the supply of moisture to plant tissues, inhibit photosynthesis, and severely reduce plant growth and yield. Thus, the application of water stress-tolerant agents can be a useful strategy to maintain plant growth under abiotic stresses. This study assessed the effect of exogenous bio-based 2,3-butanediol (BDO) application on drought and chilling response in tomato and turfgrass, and expression levels of several plant signaling pathway-related gene transcripts. Bio-based 2,3-BDOs were formulated to levo-2,3-BDO 0.9% soluble concentrate (levo 0.9% SL) and meso-2,3-BDO 9% SL (meso 9% SL). Under drought and chilling stress conditions, the application of levo 0.9% SL in creeping bentgrass and meso 9% SL in tomato plants significantly reduced the deleterious effects of abiotic stresses. Interestingly, pretreatment with levo-2,3-BDO in creeping bentgrass and meso-2,3-BDO in tomato plants enhanced JA and SA signaling pathway-related gene transcript expression levels in different ways. In addition, all tomato plants treated with acibenzolar-S-methyl (as a positive control) withered completely under chilling stress, whereas 2,3-BDO-treated tomato plants exhibited excellent cold tolerance. According to our findings, bio-based 2,3-BDO isomers as sustainable water stress-tolerant agents, levo- and meso-2,3-BDOs, could enhance tolerance to drought and/or chilling stresses in various plants through somewhat different molecular activities without any side effects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.207-213
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• 1998

These experiments were carried out to investigate the effects of electrical stimulation(ES) and delayed chilling (DC) on the quality characteristics of Hanwoo beef. The left half carcass was treated with ES(550V, 90sec)within postmortem 30min. The electrical stimulated half carcass was subjected to chilling at 16$^{\circ}C$ for 24hr, and then stored at 2$\pm$2$^{\circ}C$ for 15days (ESDC). The right half carcass was stored at 2$\pm$2$^{\circ}C$ for 15 days (NES). ESDC showed a rapid pH fall and tended to reach to pH5.54 at postmortem 2 hrs. But, there was no consistent effect of electrical stimulation and delayed chilling on meat color, cooking loss and water holding capacity. Myofibril fragmentation index was higher than that of NES during storage. ESDC showed lower shear force value and strength consistently than NES. SDS-PAGE band patterns of myofibrils showed the rapid breakdown of troponin T and troponin I band in ESDC, compared with NES, and revealed the specific band below myosin light chain-2 pattern in ESDC.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.257-262
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• 2007

The current study was conducted to investigate the optimum stunning voltage and chilling regime with emphasis on reduction in pale, soft and exudative (PSE) pork. The experiments were conducted at seven Korean major pig abattoirs using a total of 91,082 industrial population. Frequencies of PSE meat was found to be significantly (p<0.05) increased as stunning voltage was elevated from 220-240 (13.14%), 250-280 (29.32%) to 430 volts (36.74%). Chilling methods after slaughter, either with cold water showing or rapid chilling reduced PSE meat by 22% compared to a classic chiller-based slow chilling regime. The current study also revealed that chiller temperature during the first 90 minutes had a significant (p<0.001) effect on PSE incidences. Pigs chilled between -5 to $7^{\circ}C$ resulted in the lowest PSE meat (17.8%), followed by higher than $7^{\circ}C$ (21.3%) and lower than $-5^{\circ}C$ (37.5%). The current data implies that low voltage stunning method (eg., 220-240 volts), followed by rapid chilling regime, maintaining chiller temperature between approximately -5 to $7^{\circ}C$ could reduce PSE incidences.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.71-80
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• 2005

Effects of low temperature ($8^{\circ}C$) on the hydraulic conductivity of young roots of a chilling-sensitive (cucumber; Cucumis sativus L.) and a chilling-resistant (figleaf gourd; Cucurbita ficifolia Bouche) crop have been measured at the levels of whole root systems (root hydraulic conductivity, $Lp_r$) and of individual cortical cells (cell hydraulic conductivity, Lp). In figleaf gourd, there was a reduction only in hydrostatic $Lp_r$ but not in osmotic $Lp_r$ suggesting that the activity of water channels was not much affected by low root temperature (LRT)treatment in this species. Changes in cell Lp in response to chilling and recovery were similar asroot level, although they were more intense at the root level. Roots of figleaf gourd recovered better from LRT treatment than those of cucumber. In figleaf gourd, recovery (both at the root and cell level) often resulted in Lp and $Lp_r$ values which were even bigger than the original, i.e. there was an overshoot in hydraulic conductivity. These effects were larger forosmotic (representing the cell-to-cell passage of water) than for hydrostatic $Lp_r$. After a short term (1 d) exposure to $8\;^{\circ}C$ followed by 1 d at $20\;^{\circ}C$, hydrostatic $Lp_r$ of cucumber nearly recovered and that of figleaf gourd still remained higher due to the overshoot. On the contrary, osmotic $Lp_r$ and cell Lp in both species remained high by a factor of 3 as compared to the control, possibly due to an increased activity of water channels. After pre-conditioning of roots at LRT, increased hydraulic conductivitywas completely inhibited by $HgCl_2$ at both the root and cell levels. Different from figleaf gourd, recovery from chilling was not complete in cucumber after longer exposure to LRT. It is concluded that at LRT, both changes in the activity of aquaporins and alterations of root anatomy determine the water uptake in both species. To better understand the aquaporin function in plants under various stress conditions, we examined the transgenic Arabidopsisand tobacco plants that constitutively overexpress ArabidopsisPIP1;4 or PIP2;5 under various abiotic stress conditions. No significant differences in growth rates were found between the transgenic and wild-type plants under favorable growth conditions. By contrast, overexpression of PIP1;4 or PIP2;5 had a negative effect on seed germination and seedling growth under drought stress, whereas it had a positive effect under cold stress and no effect under salt stress. Measurement of water transport by cell pressure probe revealed that these observed phenotypes under different stress conditions were closely correlated with the ability of water transport by each aquaporin in the transgenic plants. Together, our results demonstrate that PIP-type aquaporins play roles in seed germination, seedling growth, and stress response of Arabidopsis and tobacco plants under various stress conditions, and emphasize the importance of a single aquaporin-mediated water transport in these cellular processes.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.87-94
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• 2011

This study was carried out to investigate the effects of hot solution soaking and chilling treatment on sprouting and enlargement of bulblets obtained through in vitro culture in Korean native lilies with ornamental values. In vitro bulblets of Lilium cernuum, L. hansonii, L. hansonii for. mutatum, L. leichtlinii, and L. tsingtauense were soaked in distilled water or 100 $mg{\cdot}L^{-1}$ $GA_3$ and $GA_{4+7}$ solution maintained at $35^{\circ}C$ for two hours (hot water treatment) and/or exposed at $4^{\circ}C$ for 0, 4, or 8 weeks (chilling treatment) and then planted in plastic trays filled with media and grown in a greenhouse at $20^{\circ}C$ and under 16 h photoperiod. In all species, no bulblet propagated by tissue culture sprouted without chilling or hot water treatment due to dormancy. For dormancy breaking, $GA_{4+7}$ hot solution treatment increasing sprouting by 55-96%, whereas distilled water or GA was not effective in sprouting. Chilling treatment for 4 weeks induced sprouting by 50-70% in L. cernuum and L. leichtlinii, whereas 8 weeks was needed for sprouting of L. hansonii and L. hansonii for. mutatum. Combined treatment of hot water and chilling treatments synergistically promoted sprouting. Especially, in L. cernuum and L. hansonii, $GA_{4+7}$ hot solution soaking prior to chilling for 4 weeks promoted sprouting by 35-45% compared with the reverse order. Enlargement of bulblets resulted from increase in fresh weight and diameter was promoted by the treatments that increased the sprouting percentage of bulblets. Only in L. cernuum, shoots emerged from bulblets soaked in hot $GA_{4+7}$ solution or chilled at $4^{\circ}C$ and shoot emergence rate was highest in bulblets soaked in hot $GA_{4+7}$ solution and then chilled for 8 weeks. From these results, the most effective method for bulblet sprouting and enlargement was to soak in hot $GA_{4+7}$ solution and then chill for 4 weeks in L. hansonii, hansonii for. mutatum, and leichtlinii, and to soak in hot $GA_{4+7}$ solution and then chill for 4 weeks in L. cernuum and tsingtauense.

• Journal of Food Hygiene and Safety
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• v.3 no.1
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• pp.27-36
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• 1988

Generally, carrier chickens contaminate the processing plant equipment to such an extent that negative chickens procell afterwards result in contaminated. meat. This study was performed to investigate the prevalence of Complliobacter jejuni in two chicken procelling plants. Altogether two hundred samples were collected from cloaca, carcasses, chilling water, and evis-cerationknives at different processing stages during the period of June to September 1987. The isolated organisms were tested for distribution of biotype, serotype. The results obtained were summarized as follows: 1. C. jejuni was isolated from 41(34.2%) of 120 chicken feces, 9(45.0%) of 20 carC888eS before chilling, 11(55.0%) of 20 carcasses after chilling, 12(60.0%) of 20 eviscerationlmives. The evilceration knives and chilling water were considered as major means of croll contamination. 2. In biotyping 82 isolates of C. jejuni, 64(78.1%) were cl888ified as biotype I, and 18(21.9%) belonged to biotype II. 3. In serotyping 82 isolates of C. jejuni, 64(78.1%) were identified as serotype LIO 37, and 18(21.9%) were untypable.