• Applied Biological Chemistry
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• v.29 no.4
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• pp.366-371
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• 1986

Fatty acid compositions of Panax ginseng leaves (6 year) grown under different light intensity in field and of the detached leaves exposed to high temperature (20 hours) were investigated by gas chromatography. Linoleic, linolenic, palmitic and palmitoleic acid were the major components(80%) of leaf lipid. The higher the growth light intensity, the lower the percentage of unsaturated acids or bonds, indicating metabolic adaptation to high temperature. Pattern similarity of fatty acid composition was little changed until 20% light but significantly different at 30%, suggesting 20% as limitation light intensity. The close similarity of fatty acid composition between the loaves grown under 30% light and the one at harvest rises uncertainty between adaptation to high temperature and senescence. Total fatty acid content decreased with the increase of light intensity. Short term high temperature $(25^{\circ}C\;or\;35^{\circ}C)$ increased total fatty acid content, unsaturated acid percentage and insignificant difference in pattern similarity of composition.

• Korean Journal of Plant Resources
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• v.31 no.5
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• pp.522-530
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• 2018

Brachypodium distachyon has been developed as a monocot model plant for temperate grasses and bioenergy crops. Although B. distachyon research is moving forward rapidly, the study of photoresponses has not been explored. To extend our knowledge of responses to light in monocots, we performed photoresponse analysis of B. distachyon using two inbred lines, Bd21 and Bd21-3. In this study, we first compared growing phenotypes between the two lines and investigated coleoptile and primary leaf growths under dark, far-red, red, and white light conditions. The results showed that the growth of the two lines were similar until tillering stage, but other developmental stages from heading to senescence were much delayed in Bd21-3, which resulted in increased height and tiller numbers. Under different light conditions, primary leaf lengths were kept increasing during the growth period, whereas the coleoptile extension was inhibited 4 to 7 days after growth depending on the light conditions applied. These results suggest that the responses to light in B. distachyon can be examined by measuring coleoptile lengths approximately 7 days after seedling growth. Moreover, we selected light-responsive genes known in Arabidopsis thaliana, such as chlorophyll A/B binding protein (CAB), light-harvesting chlorophyll binding protein (Lhcb) and chalcone synthase (CHS), and confirmed their light-induced gene expression in B. distachyon. Therefore, the present study suggests that the inhibition of coleoptile growth can be used as the parameter to analyze photoresponses in the monocot model plant, and also provide the reference genes whose expression is induced by far-red and red light treatment.

• Journal of Korean Society of Forest Science
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• v.72 no.1
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• pp.37-44
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• 1986

Seasonal changes of water relations parameters were obtained from p-v curves in leaves of Quercus grosseserrata and Quercus acutissima. The osmotic pressure at full hydration, ${\pi}_o$, and osmotic pressure at incipient plasmolysis, ${\pi}_p$, were high in newly emerged leaves but decreased with leaf development in each of the species. Water deficit at turgor loss was 10 to 20% in each of the species during the growing season. Maximum bulk elastic modulus in cell walls at full turgor, Emax, rises rapidly with leaf development before senescence in each of the species. Seasonal change of number of osmoles solute in symplasm per dry weight, Ns/DW, was higher in Quercus grosseserrata leaves than Quercus acutissima leaves, while relative water content (Vp/Vo, $RWC^*$, Vo/Vt) was relatively constant in each of the species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.422-426
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• 2009

Sweetpotato is one of the important starch crops, current more considered as an industrial crop rather than food because it has higher starch content (over 80% of biomass), it is used for bio resources for industrial area. In this study, we generated S598A (a mutant gene of oat phytochrome A) sweetpotato plant using Agrobacterium-transformation method. Morphological characteristics of S598A plant were compared with the wild type sweetpotato, S598A had darker green leaves, increased chlorophyll content higher than to two-fold, delayed leaf senescence, shorter plant height (60% shorter than that of the wild type), more number of leaves and petioles about 1.8-fold, shorter petiole length (30% shorter), 1.2-fold more branches and 1.6-fold thicker stem diameters. From this study, S598A plants with such phenotypic characteristics might be able to use the solar energy efficiently, to have increased tolerance to biotic and abiotic stresses and finally to increase productivity (not only starch yield but also root biomass yield). S598A sweetpotato lines are under field trials.

• Journal of the Korean Society of Tobacco Science
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• v.15 no.2
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• pp.152-160
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• 1993

Using a flue- cured tobacco variety, KF 109, effect of growth regulators(fatty alcohol and C- MH) on the change of protein, DNA, and RNA were investigated. Generally, inhibition of DNA synthesis was observed soon after become notably reduced when checked on 14 days after the treatment. Fatty alcohol treatment appeared to alleviate the inhibition of DNA synthesis caused by the C - MH treatment. It was also observed that in the tips DNA content increased slightly at the early stage after the C - MH treatment but evident reduction of it was resulted from 7th day after the treatment. RNA content in cutters and tips was increased initially but variable transcription inhibitory activities - not so obvious as was observed in DNA synthesis - according to leaf positions were shown thereafter. Ripening of leaves probably due to senescence was advanced by the treatment of the growth regulators. DNA content in root was relatively higher in plants treated with the growth regulators while it was clearly decreased in stalk, However, RNA contents in tissue of stalk and root was not different with that of foliage. Increase of protein content in foliage as well as in stalk was evident 14 days after dual treatment of fatty alcohol and C - MH.

• Molecules and Cells
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• v.19 no.3
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• pp.342-349
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• 2005

Cytokinins are adenine derivatives that regulate numerous plant growth and developmental processes, including apical and floral meristem development, stem growth, leaf senescence, apical dominance, and stress tolerance. However, not much is known about how cytokinin biosynthesis and metabolism is regulated. We identified a novel Arabidopsis gene, ALL, encoding an aldolase-like enzyme that regulates cytokinin signaling. An Arabidopsis mutant, all-1D, in which ALL is activated by the nearby insertion of the 35S enhancer, exhibited extreme dwarfism with rolled, dark-green leaves and reduced apical dominance, symptomatic of cytokinin-overproducing mutants. Consistent with this, ARR4 and ARR5, two representative primary cytokinin-responsive genes, were significantly induced in all-1D. Whereas SHOOT MERISTEMLESS (STM) and KNAT1, which regulate meristem development, were also greatly induced, expression of REV and PHV that regulate lateral organ polarity was inhibited. ALL encodes an aldolase-like enzyme that belongs to the HpcH/HpaI aldolase family in prokaryotes and is down-regulated by exogenous cytokinin, possibly through a negative feedback pathway. We propose that ALL is involved in cytokinin biosynthesis or metabolism and acts as a positive regulator of cytokinin signaling during shoot apical meristem development and determination of lateral organ polarity.

• Journal of agriculture & life science
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• v.44 no.3
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• pp.1-6
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• 2010

The influence of sodium hypochlorite and ethephon on the germination of narrow-leaved purple coneflower (Echinacea angustifolia) was investigated. Treatment of seeds with ethephon (1 mM) for 2 h followed by soaking in 0.525% sodium hypochlorite greatly increased germination (>90%). The treatment of seed with a combination of sodium hypochlorite and ethephon shortened number of days required to reach 50% of the final germination ($T_{50}$) from 4.2 days in control to 1.1 days. Seedlings grown from ethephon-treated seeds had shorter and thicker hypocotyls and roots with higher dry weights compared to the control. The same trend was observed during seedling emergence from soil. Ethephon treatment longer than 2 h resulted in weaker seedlings, probably due to leaf senescence. Anthocyanin content in seedling leaves increased linearly from 0.04 mg/g fresh weight in control to 3.72 mg/g fresh weight in 24 h treatment as the time of seed exposure to ethephon increased. Seed treatment with bleach and ethephon may well be practiced to facilitate the establishment of E. angustifolia in the field.

• Journal of People, Plants, and Environment
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• v.22 no.3
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• pp.233-239
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• 2019

This study was conducted in order to predict the vase life of cut lily 'Woori Tower' flowers using a non-destructive thermal imaging technique. It was found that the temperature of cut lily flowers was maintained at 20℃ and was slightly lower than the air temperature until they bloomed. On the 11th day, when flowers bloomed, the temperature of leaves and flowers was measured to be 18.75±0.38℃ and 19.23±0.32℃ respectively, and their difference with ambient temperature was over 3℃. The flower temperature increased slightly when the vase life of cut lily flowers ended, and the temperature difference between the air and leaf temperature (1.77℃) and between the air and flower temperature (1.39℃) got smaller. No visible aging symptom was observed, but it was found that the temperature had risen due to water losses and less functional stomata. The vase life of cut lily flowers can be predicted based on changes in temperature and it will be also possible to predict the potential quality and vase life of cut flowers before harvesting them in greenhouses.

• Horticultural Science & Technology
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• v.28 no.4
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• pp.609-617
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• 2010

The effect of vase water temperature and leaf number on water relations and senescence responses was determined in cut roses. Freshly harvested 'Red Sandra' roses were re-trimmed to 50 cm leaving two or four upper leaves and held in one of three solutions: ambient temperature distilled water ($23^{\circ}C$; AT-DW), low temperature distilled water ($7^{\circ}C$; LT-DW) and low temperature preservative solution (LT-PW). Flowers were kept in an environmental controlled room. Treatment effects evaluated were vase life, flower diameter, and changes in fresh weight and water uptake. Differences in water relations were determined by measuring $CO_2$ assimilation, stomatal conductance, and stem water flux rate (SFR). The water uptake rate was significantly increased in roses in LT-DW and decreased in those in LT-PW. While showing lower solution uptake rate during vase period, roses in LT-PW exhibited greatest fresh weight, longest positive water balance duration and largest flower diameter. Flowers with two leaves attached exhibited a higher fresh weight and improved water balance, thereby extending vase life. $CO_2$ assimilation rate and stomatal conductance were significantly decreased by placing flowers in LT-PW, yet increased by reducing leaf number to two leaves on the flower stems. Compared to the upper stem, the SFR of the basal stem of roses in AT-DW was lower, whereas SFR in basal stems of roses in LT-DW was much higher, suggesting that low-temperature water improved the hydraulic conductance in the stems. In contrast, roses in LT-PW had a stable SFR during the experimental period and displayed a similar pattern in SFR between upper and basal portions of the stems. Consequently, the vase life of cut roses in LT-PW and LT-DW was extended by more than eight and four days, respectively, compared to those in AT-DW.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.266-272
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• 2015

High temperature impairs rice grain yield and quality. To understand the effect of high temperature on leaf physiological activity and grain filling, two cultivars of rice that Dongan and Ilpum were exposed to high temperature during ripening stage. Grain filling rate, perfect grain ratio and grain weight of high temperature ($27^{\circ}C{\pm}4^{\circ}C$) treated both rice cultivars were decreased than those of control temperature ($22^{\circ}C{\pm}4^{\circ}C$) treated. The reduction rates of grain filling ratio, perfect grain ratio and grain weight of high temperature treated to control treated rice were higher in Ilpum than Dongan. Chlorophyll contents of rice leaves under high temperature at early ripening stage were higher than those of control temperature, but those were slowly decreased with no difference between temperature treatment since at mid ripening stage. Although chlorophyll a/b ratio under high temperature was decreased from heading to 15 days after heading, that was gradually increased since 15 days after heading. Protein concentrations of rice leaves for ripening stage was a similar pattern with chlorophyll changes. The rate of photosynthesis at 14 days after heading under high temperature was higher than those of control temperature, but there was no difference at those of 7 and 34 days after heading between two temperature treatment. Free sugars under high temperature treated leaves were lower than control temperature. Consequently, these results exhibit that high temperature accelerate leaf physiological activity as chlorophyll synthesis and photosynthesis rate unlike the deterioration of grain filling.