• Journal of Photoscience
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• 제3권1호
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• pp.15-21
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• 1996

To investigate the chilling sensitivity related injuries in the photosynthetic apparatus of cucumber leaves, the light-chilling induced alterations of chlorophyll fluorescence transients in cucumber leaves were compared with those in pea leaves. As an early effect of light-chilling, an increase in Fp/Fm$^*$ was observed in both pea and cucumber leaves, which was saturated by about 6 h chilling. However, the saturated value of Fp/Fm was almost 1.0 in cucumber, in contrast to about 0.8 in pea. During the recovery period after 24 h chilling, the light-chilling induced changes in pea seemed to be reversed, but those in cucumber leaves were thought to be irreversible, because Fo was increased significantly. Light-chilling caused significant decreases in qQ and qE in cucumber leaves, but qR was increased until 6 h, and decreased thereafter. In both pea and cucumber leaves, Fm was increased by 2 h dark treatment. The Fm from the predarkened pea leaf discs was higher than the value from the preilluminated ones during the whole period of light-chilling (500 $\mu$mol m$^{-2}$s$^{-1}$ PAR). However, the predarkened cucumber leaf discs showed a reduction in Fm and an increase in Fo during the 2 h chilling in the light. These results indicate that the causes of chilling sensitivities in photosynthetic apparatus of cucumber leaves are possibly related with the damage in PSI reaction center and the ability of acidification of lumen by PSII.

• BMB Reports
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• 제29권5호
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• pp.398-404
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• 1996

Light-chilling effects were investigated in chilling-sensitive cucumber (Cucumis sativus L. cv. Ilmichungjang) and chilling-resistant pea (Pisum sativum L. cv. Giant) leaf discs in relation to possible damage in D1 protein. In both plants, dark-chilling did not cause any noticeable changes in (Fv)m/Fm and lincomycin did not affect the decrease in (Fv)m/Fm caused by light-chilling. This result suggests that the de novo synthesis of D1 protein did not occur actively during light-chilling. In pea light-chilled for 6 h. the decreased (Fv)m/Fm was partly recovered in the dark, and almost complete recovery was observed in the light. In cucumber light-chilled for 3 h. the reduced (Fv)m/Fm decreased further for the initial 2 h recovery process in the light regardless of the treatment of lincomycin and recovered very slowly. In both plant species, the treatment of lincomycin inhibited the recovery process in the light, but did not significantly inhibit the process in the dark. In cucumber leaves pulse-labeled with $[^{35}S]Met$, the labeled band intensities of isolated pigment-protein complexes were almost the same during the 6 h light-chilling, but significant decreases in band intensities were observed during the 3 h recovery period. This result suggests that the irreversibly damaged D1 protein was degraded during the recovery period. However, no noticeable changes were observed in the pea leaves during the 12 h chilling and 3 h recovery period. The polyacrylamide gel electrophoresis of the pigment-protein complexes showed that the principal lesion sites of light-chilling were different from those of room temperature photoinhibition.

• 식물조직배양학회지
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• 제24권2호
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• pp.99-101
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• 1997

나팔수선 킹알프레드의 화경배양에서 얻은 대량의 소자구를 비대시키기에 적합한 호르몬 농도, 저온처리기간, 저온 처리 후 구비대에 적합한 호르몬 농도를 구명코자 하였다. 분화된 식물체의 구비대 및 생육은 BA 2.5mg/L에 NAA 2.5mg/L이 첨가된 MS배지에서 높았다. 자구비대를 위한 저온처리 기간은 8주간이 좋았으며 저온처리후 배양은 NAA 1mg/L가 첨가된 배지가 구비대에 가장 효과적이었다.

• 동아시아식생활학회지
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• 제23권4호
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• pp.487-495
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• 2013

돼지고기의 저지방 부위인 뒷다리살과 등심을 진공포장하여 $-20^{\circ}C$에서 3개월간 동결한 후 해동하였다. 해동육을 $3^{\circ}C$에 냉장하면서 냉장기간에 따른 생육과 가열육의 물리적 특성 변화를 확인하였다. 생육의 경우, 뒷다리살은 해동직후(냉장 0일)에 비하여 냉장 4일에 pH 값, $L^*$값, 드립 감량, 보수력, 점성이 상승한 반면, 가열감량, 경도 및 저작성은 유의적으로 낮아지는 현상을 보였다(p<0.05). 등심은 해동 후 냉장 2일에 이와 같은 같은 현상이 나타났다. 가열육의 물리적 특성 변화는 두 부위 모두 생육의 경우와 비슷한 경향을 보였으나, pH 값, $L^*$값 및 $a^*$값은 해동 후 냉장 중 유의적 차이를 보이지 않았다. 생육과 가열육의 탄력성 및 응집성은 두부위 모두 해동 후 냉장 중에 유의적 차이를 나타내지 않았다. 뒷다리살과 등심은 각각 해동 후 냉장 4일과 2일에 연도가 유의적으로 향상되었다(p<0.05).

• The Korean Journal of Ecology
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• 제19권2호
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• pp.151-163
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• 1996

To investigate the early symptoms of light-chilling, alterations of chlorophyll fluorescence transients were monitored in cucumber (Cucumis sativus L. cv. Ilmichungjang) leaves. During 24 h chilling, decreases in (Fv)m/Fm, qE and qQ, and an increase in Fo were observed. The chilling effects were not recovered at room temperature, and a significant increase in Fo was observed during the recovery period. After 6 h chilling, ‘dip’(D) level of the transients became obscure, and the negative slope after ‘peak’(P) disappeared. The first derivative (dFv/dt) of the fast fluorescence rise curve was used to obtain more accurate information about the changes in the transients. The maximal rate of the fluorescence increase in the D-p rise curve (Fr) has been the most frequently used chilling stress indicator. However, a correct value of Fr could not be measured when the D level became obscure. This problem was overcome by introducing a new indicator, HFr (dFv/dt at Fv = 1/2 (Fv)m), and HFr gave very similar values to Fr. To monitor the changes in curvature around D level, another new parameter, ${\Delta}S$(D-Fr), was also introduced. These three parameters decreased very sensitively during light-chilling. In addition, increases in these parameters were observed during the first 2 h chilling, but this increase in Fr was also observed in pea leaf discs dark-chilled for 15 min, suggesting that this very early change is a common response to chilling in both pea and cucumber leaves. Quenching coefficients were also very sensitive to chilling, especially qE. Discussion on the usage of these parameters as chilling stress indicators is given in the text.

• 한국작물학회지
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• 제24권2호
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• pp.17-26
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• 1979

Indica \times Japonica 교잡에 의해 육성된 수도신품종들의 유묘기 내냉한계와 내냉발현특성을 Janica품종들과 비교 고찰하고자 10개 품종을 유묘기 내냉성이 제일 약한 제 3 엽기에 주간 11\circ C야간 5\circ C의 저온조건에 0, 3, 4, 5, 8, 10일 처리한 결과는 다음과 같다. 1. 저온처리 전후에 주야 26\circ C / 18\circ C에서 생장한 파종 후 35일묘의 건물중이 무처리묘의 90% 이상이 되는 최장저온처리기간은 신품종들의 경우 0.8~2.8일 간으로써 특히 조생통일이 짧고 밀야 2003가 길었으며, Japonica 품종들의 경우 4.0~5.2일간으로써 신품종들보다 가역적 내냉한계기간이 배정도 길었다. 2. 저온처리에 따른 냉해발현 종료후 묘생존율이 90%이상되는 최장저온처리기간은 신품종들의 경우 3.0~5.6 일간으로써 수원 258호가 제일 짧고 수원 25001가 제일 길었으며, Japonica 품종들은 공시품종 모두 10일간 이상으로 신품종들보다 비가역적 내냉한계기간이 2~3배 이상 길었다. 3. 저온처리중 엽신변색고사율(y_1) 및 묘고사율(y_2), 저온처리 후 발현된 모신변색고사율(y_3), 묘고사율(y_4), 냉해를 받은 35일묘의 초장(y$_{5}$)과 건물중(y$_{6}$)은 모두 저온처리기간(x)과 고도로 유의한 상관성을 보였는데 특히 y_1, y_3, y$_{6}$와 높은 상관성을 보였으며, y_1~y$_{6}$들 상호간에도 모두 고도로 유의한 상관성을 보였으나 특히 y_1과 y_3, y_3와 y$_{6}$의 상관성이 컸다. 4. 냉해징상들의 발현순서와 상태들간의 상관성 분석결과로부터 가역적 및 비가역적, 직접적 및 간접적 냉해의 발생과 그들의 복합현상으로써 결과되는 관찰되는 냉해징상의 발현과정 모식도를 작성하여 그림 5에 제시하였다. 5. 수도유묘의 내냉성 평가에 있어서 가역적 피해와 비가역적 피해를 종합적으로, 그리고 정량적으로 나타내며 일반적으로 냉해를 나타내는 조사형질들 중 냉해에 가장 예민한 반응을 보이는 건물중율을 1차요인으로 취급할 것으로 제의한다.

• 한국작물학회지
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• 제37권3호
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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.

• 한국가금학회지
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• 제24권1호
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• pp.17-28
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• 1997

This experiment was carried out to investigate the effects of different chilling and packing methods on physico-chernical properties of cold-stored chicken breast and thigh meats. Dehoned chicken breast and thigh meats were chilled either air spray or ice-water immersion method. The chilled meats were either vacuum packed or atmosphere packed, and stored at -2˚C for 1, 3, 7, 11, 15, and 20 days. The pH of both immersion chilled meats and vacuum packed meats were higher than those of their counterparts(P<0.05). The pH of atmosphere packed meats increased as the storage period extended. The moisture contents of vacuum packed meats were remarkably higher than those of atmosphere packed meats. The pH of all treatments decreased as the storage period extended. The shear values of air spray chilled and vacuum packed breast meats were significantly higher than immersion chilled and vacuum packed ones. However, immersion chilled and atmosphere packed breast meats were significantly higher than those of air spray chilled and atmosphere packed breast meats. The shear values of immersion chilled and vacuum packed thigh meats were significantly higher than those of immersion chilled and vacuum packed thigh meats. In atmosphere packed thigh meats, air spray chilling method showed higher shear values than those of immersion chilled thigh meats. In thigh muscle, tenderness values tended to decrease as the storage period extended(P<0.05). Contents of water soluble proteins of vacuum packed and air spray chilled breast and thigh meats were higher than those of their counterparts as the storage period extended(P<0.05). The contents of water soluble proteins significantly decreased as the storage period extended. Salt soluble proteins of atmosphere packed breast and thigh meats were remarkably higher than those of vacuum packed ones(P<0.05). Total lipid contents of atmosphere packed and air spray chilled breast and thigh meats were higher than those of atmosphere packed and immersion chilled meats as the storage period extended. The vacuum packed meats were significantly higher in total lipid contents than those of atmosphere packed meats. The storage period decreased the total lipid contents of cold chicken, Major fatty acids in cold-stored chicken were oleic, palmitic, linoleic and stearic acids, regardless of chilling method. Unsaturated fatty acids of all treatments decreased, but saturated fatty acids increased as the storage period extended.

• 한국축산식품학회지
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• 제25권2호
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• pp.127-133
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• 2005

진공 포장한 우육을 $0\pm1^{\circ}C$에서 8주간 냉장하면서 숙성 효과를 조사하였다. 우육의 경도, 저작성 및 전단력은 냉장 5주까지 저하되어 연화 효과가 있었으나 6주 후에는 그 효과가 없었다. 근원섬유단백질의 추출성, Mg-ATPase활성 및 근원섬유 소편화도는 6주까지 높아졌으나 그 후 8주까지 변화하지 않았다. 우육의 색도는 냉장 8주까지 양호하였다. 우육의 기호도는 5주까지 향상되었으나 6주 이후에는 오히려 저하되었다. 진공포장하여 냉장한 우육의 숙성 효과는 5주까지 기대할 수 있었다.

• 한국농림기상학회지
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• 제7권3호
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• pp.185-191
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• 2005

An accurate prediction of dormancy release and bud burst in temperate zone fruit trees is indispensable for farmers to plan heating time under partially controlled environments as well as to reduce the risk of frost damage in open fields. A thermal time-based two-step phenological model that originated in Italy was applied to two important grapevine cultivars in Korea for predicting bud-burst dates. The model consists of two sequential periods: a rest period described by chilling requirement and a forcing period described by heating requirement. It requires daily maximum and minimum temperature as an input and calculates daily chill units (chill days in negative sign) until a pre-determined chilling requirement for rest release is met. After the projected rest release date, it adds daily heat units (anti-chill days in positive sign) to the chilling requirement. The date when the sum reaches zero isregarded as the bud-burst in the model. Controlled environment experiments using field sampled twigs of 'Campbell Early' and 'Kyoho' cultivars were carried out in the vineyard at the National Horticultural Research Institute (NHRI) in Suwon during 2004-2005 to derive the model parameters: threshold temperature for chilling and chilling requirement for breaking dormancy. The model adjusted with the selected parameters was applied to the 1994-2004 daily temperature data obtained from the automated weather station in the NHRI vineyard to estimate bud burst dates of two cultivars and the results were compared with the observed data. The model showed a consistently good performance in predicting the bud burst of 'Campbell Early' and 'Kyoho' cultivars with 2.6 and 2.5 days of root mean squared error, respectively.