• Horticultural Science & Technology
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• v.29 no.2
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• pp.135-143
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• 2011

In the Doritaenopsis hybrid, like most of the orchid species and hybrids, temperature is crucial for the vegetative-to-reproductive transition, and low temperature is required for bud differentiation. To understand the molecular mechanism of this process, an orchid GIGANTEA (GI) gene, DhGI1, was isolated and characterized by using the rapid amplification of cDNA ends (RACE) PCR technique. Sequence analysis showed that the full-length cDNA is 4,022 bp with a major open reading frame of 3,483 bp, and the amino acid sequence showed high similarity to GI proteins in Zea mays, Oryza sativa, Arabidopsis thaliana and other plants. Semi-quantitative RT-PCR revealed that DhGI1 was expressed throughout development and could be detected in roots, stems, leaves, peduncles and flower buds. The expression level of DhGI1 was higher when the plants were flowering at low temperature (22/$18^{\circ}C$ day/night) than the other growth stages. Further analysis indicated that the accumulation of DhGI1 transcripts was significantly increased at low temperature, and concomitantly, initiation of the peduncle was observed. However, DhGI1 levels were low under high temperature (30/$25^{\circ}C$) conditions, and flower initiation was inhibited. These results indicate that the expression of DhGI1 is regulated by low temperature and that DhGI1 may play an important role in inflorescence initiation in this Doritaenopsis hybrid at low temperatures.

• Korean Journal of Agricultural and Forest Meteorology
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• v.4 no.3
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• pp.133-140
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• 2002

Site-specific minimum temperature forecasts are critical in a short-term decision making procedure for preventive measures as well as a long-term strategy such as site selection in fruits industry. Nocturnal cold air pools frequently termed in mountainous areas under anticyclonic systems are very dangerous to the flowering buds in spring over Korea, but the spatial resolution to detect them exceeds the current weather forecast scale. To supplement the insufficient spatial resolution of official forecasts, we developed a GIS - assisted frost risk assesment scheme for using in mountainous areas. Daily minimum temperature data were obtained from 6 sites located in a 2.1 by 2.1 km area with complex topography near the southern edge of Sobaek mountains during radiative cooling nights in spring 2001. A digital elevation model with a 10 m spatial resolution was prepared for the entire study area and the cold air inflow was simulated for each grid cell by counting the number of surrounding cells coming into the processing cell. Primitive temperature surfaces were prepared for the corresponding dates by interpolating the Korea Meteorological Administration's automated observational data with the lapse rate correction. The cell temperature values corresponding to the 6 observation sites were extracted from the primitive temperature surface, and subtracted from the observed values to obtain the estimation error. The errors were regressed to the flow accumulation at the corresponding cells, delineating a statistically significant relationship. When we applied this relationship to the primitive temperature surfaces of frost nights during April 2002, there was a good agreement with the observations, showing a feasibility of site-specific frost warning system development in mountainous areas.

• Korean Journal of Pharmacognosy
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• v.44 no.3
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• pp.291-297
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• 2013

Sophorae Flos (SF), a composite of flowers and flower-buds of Sophora japonica, has long been used in traditional Korean and Chinese medicines for the treatment of hemostasis and inflammation. In this study, we investigated anti-inflammatory effect of four EtOH extracts at the difference in blooming stages of flowers on LPS-induced inflammation in RAW264.7 cells. We classified the flowers of Sophora japonica with SF-1 (length of flower is shorter than calyx), SF-2 (length of calyx is shorter than flower), SF-3 (full bloom), and SF-4 (not blooming at all). We examined HPLC analysis, whether quercetin and rutin are major component of these Sophorae Flos extracts or not. As a result, SF-1 contained quercetin, but the others did not. In addition, quercetin, SF-1, and SF-4 act on the suppression of pro-inflammatory mediators including inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, nitric oxide (NO), prostaglandin E2 ($PGE_2$) against lipopolysaccharide (LPS)-induced activation in RAW264.7 cells. Of these, SF-1 showed the best anti-inflammatory effect. These results suggest that Sophorae Flos with the highest content of quercetin would be used for the treatment of various inflammation diseases.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.1
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• pp.1-9
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• 2006

Regardless of the recent observed warmer winters in Korea, more freeze injuries and associated economic losses are reported in fruit industry than ever before. Existing freeze-frost forecasting systems employ only daily minimum temperature for judging the potential damage on dormant flowering buds but cannot accommodate potential biological responses such as short-term acclimation of plants to severe weather episodes as well as annual variation in climate. We introduce 'dormancy depth', in addition to daily minimum temperature, as a complementary criterion for judging the potential damage of freezing temperatures on dormant flowering buds of grape vines. Dormancy depth can be estimated by a phonology model driven by daily maximum and minimum temperature and is expected to make a reasonable proxy for physiological tolerance of buds to low temperature. Dormancy depth at a selected site was estimated for a climatological normal year by this model, and we found a close similarity in time course change pattern between the estimated dormancy depth and the known cold tolerance of fruit trees. Inter-annual and spatial variation in dormancy depth were identified by this method, showing the feasibility of using dormancy depth as a proxy indicator for tolerance to low temperature during the winter season. The model was applied to 10 vineyards which were recently damaged by a cold spell, and a temperature-dormancy depth-freeze injury relationship was formulated into an exponential-saturation model which can be used for judging freeze risk under a given set of temperature and dormancy depth. Based on this model and the expected lowest temperature with a 10-year recurrence interval, a freeze risk probability map was produced for Hwaseong County, Korea. The results seemed to explain why the vineyards in the warmer part of Hwaseong County have been hit by more freeBe damage than those in the cooler part of the county. A dormancy depth-minimum temperature dual engine freeze warning system was designed for vineyards in major production counties in Korea by combining the site-specific dormancy depth and minimum temperature forecasts with the freeze risk model. In this system, daily accumulation of thermal time since last fall leads to the dormancy state (depth) for today. The regional minimum temperature forecast for tomorrow by the Korea Meteorological Administration is converted to the site specific forecast at a 30m resolution. These data are input to the freeze risk model and the percent damage probability is calculated for each grid cell and mapped for the entire county. Similar approaches may be used to develop freeze warning systems for other deciduous fruit trees.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.69-75
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• 1985

Field experiments were performed to obtain the basic information of flowering order and variation of yield characteristics by capsule position in sesame. Flowering order was advanced regularly about one day interval from 5th capsule-setting node to upper node. Developing order of flowers at the same nodes, the chief bud was generally flowered eariler than side buds, 3 days below 8th node, 2 days from 9th to 16th node, and 2 - 3 days above 17th node. The number of capsule per plant and total grains were 98% from 1st to 16th capsule - setting node, but the number and the weight of matured grain were 99% from 1st to 13th node. The weight of matured grain among nodes was the heaviest at 5th capsule - setting node. The variation of yield characteristics among nodes was higher than individual plants. Yield characteristics of 6th node was shown lowest variation in comparision with those of other nodes.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.4
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• pp.229-236
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• 2003

This pot experiment was conducted in order to observe the effects of application of combined micronutrients(T$_1$: control. T$_2$; Fe, T$_3$; Fe+Mn, T$_4$； Fe＋Mn＋Cu, T$_{5}$; Fe+Mn+Cu＋Zn, T$_{6}$；Fe+Mn+Cu＋Zn+Mo, T$_{7}$； Fe+Mn+Cu+Zn+Mo+B) on forage performance of pure and mixed cultures of orchardgrass and white clover. The first part was concerned with the changes in the growth, summer depression, and flowering of forage plants. The results obtained are summarized as follows: 1. The T$_3$and T$_{6}$ resulted in a wide chlorosis induced by the Fe-deficiency on orchardgrass. Chlorosis was significantly reduced by the T$_4$and T$_{5}$, whereas the T$_{7}$, T$_2$, and T$_1$showed normal growth without chlorosis symptoms. The T$_{7}$ resulted in the best growth of orchardgrass both in the pure and mixed swards. There was no chlorosis symptom on white clover. whereas the T$_1$, T$_2$and T$_{7}$ showed a relatively good growth with deep green leaf-colour compared with the other treatments in the pure culture. 2. In summer, a summer depression occurred in orchardgrass: this was significantly reduced by the T$_1$and T$_{7}$. The treatments with chlorosis symptoms in orchardgrass partly induced a lodging. Summer depression in white clover did not occur. 3. In the pure culture, the T$_{7}$ and T$_2$in white clover resulted in many flowers and flower-buds compared with the other treatments. The T$_{7}$, especially, showed a long blooming period and an early full bloom compared with the other treatments, whereas the T$_{6}$ and is showed inferior numbers of them. Only the T$_{7}$ resulted in more flowers than flower-buds, and above 1 in the flower/flower-bud ratio except the T$_{6}$ in the mixed culture. 4. It was recognized that the chlorosis of Fe-deficiency occurred not only from the unsuitable ratios of Fe/Mn and Fe/Mo but also from the unsuitable mutual ratios among the cations(Fe, Mn, Cu and Mn), between the anions(Mo and B), and their total ion concentration. It was observed the multiple interactions of Fe${\times}$Mn${\times}$Mo${\times}$B, and the distinct role of B as a regulator.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1319-1328
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• 2011

Rhododendron brachycarpum is a evergreen broad-leaved shrub and belongs to the Ericaceae family and the Rhododendron genus. It is well known for its beautiful leaves and flowers. There are 11 species of the Rhododendron genus in Korea. It includes 3 species - Rhododendron brachycarpum, Rhododendron aureum Georgi and Rhododendron brachycarpum var. roseum Koidz. They grow naturally over 1,000 meters above sea level of the Baekdu Mountain Range in Korea. These habitats, according to investigations of 9 Rhododendron brachycarpum natural habitats, are mostly located on the slope of mountains facing north at an altitude of 1,200 m to 1,526 m above sea level with angle of inclination from 30 degrees to 45 degrees. Based on the result of vegetation analysis of dominance species in the quadrates, there are Quercus aliena, Quercus mongolica Fisch. ex Ledeb, Abies holophylla in species of upper trees, and so on. Dominant species of woody plants in tree layer are Quercus aliena, Quercus mongolica Fisch. ex Ledeb, Abies holophylla, Betula platyphylla and Veeatrum patulum Loes. fil, Erythronium japonicum, Dryopteris crassirhizoma, Paeonia japonica var. glabra Makino are founded in herbaceous plants. And we can see another result of the investigation that the flowering rates of the plants with the buds are highly ranked mountains such as Mt. Hambaek 68%, Mt. Gyebang 40%, Mt. Yagksu 9%, Mt. Gaein 7% and Mt. Seolag 0%. The results show that there are 24 over 15-year-old Rhododendron brachycarpums in Mt. Odae and are 56 under 15-year-old trees in Mt. Hambaek and are no trees in Mt. Gyebang and are 9 over 30-year-dead trees only in Mt. Taebaeg. Out of found trees, the highest tree is 7 m in height and 0.6 m in diameter. Also this result shows what are the vulnerability factors of the natural habitats. They are as follows: indiscriminate trails in mountains, damages by mountain climbers, uncareful plant collecting, the fierce competitions with other plants such as Acer pseudosieboldianum var. ishidoyanum Uyeki, Quercus aliena, Celastrus orbiculatus and damages by disease and insect, unusual temperature in natural habitats, etc. Rhododendron brachycarpums have high ornamental value and excellent pharmaceutical effect. But the areas of its habitats decrease dramatically. So we need measures to protect and their natural habitats. It is necessary that we conductfurther investigations to designate conservation area for Rhododendron brachycarpums.

• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.239-243
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• 2006

This research compared growth and flowering of potted $Viola{\times}wittrockiana$ 'Majestic GT Scarlet Shadow' in various mixtures of recycled perlite and cellular glass foam (CGF). The crop was cultured in a mat subirrigation system. Numbers of leaves, opened flowers, flower buds, and branches, fresh and dry weights of shoot, leaf area, and total chlorophyll concentration were the greatest in plants grown in the medium of used perlite + granular rockwool+ peatmoss (25:50:25, v/v/v). Plant height and length of the longest root were the highest and longest, respectively, in plants grown in the medium of CGF+peatmoss (25:75, v/v). The medium of CGF+peatmoss (25:75, v/v) was better than the medium of used perlite+peatmoss (25:75, v/v) in plant growth. The medium of CGF + granular rockwool (25:75, v/v) was poorer than the medium of recycled perlite + granular rockwool (25:75, v/v).

• Horticultural Science & Technology
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• v.18 no.3
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• pp.378-382
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• 2000

For the production of second crop in 'Campbell Early' grape, the primary shoots were pruned at 3rd, 6th or 9th nodes from the shoot bases on 13 days, 23 days and 33 days after full bloom date on 7th June. Secondary shoots were sprouted 7~8 days after the pruning, and it took 19~25 days for the flowering on the secondary shoots. The flower cluster number on secondary shoots were 2.8 for 13 days after full bloom, and 3.2 for 23 days and 33 days after full bloom, meaning little effect by pruning time. The 3rd node pruning produced 2~2.4 flower clusters with flower cluster length of 9.3~10.4 cm, while the 6th or 9th node pruning produced 3.1~3.8 flower clusters with flower cluster length of 12~14.9 cm, showing superior flower cluster length for the 6th or 9th node pruning. The secondary shoots developed from the buds pruned 13 days after full bloom with pruning bud positions of 6th nodes demonstrated superior fruits with higher soluble solids and lower acidity than the rest of the pruning times and positions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.3
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• pp.128-134
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• 1987

This experiment was conducted to evaluate the effects of cutting in field and solution culture. Periodical samplings of alfalfa in cutting and uncutting plots were taken to measure nodule development and nodule activity. Regrowth of plant and nodule development after shoot cutting by different heights and nodule removal at different levels were investigated in solution culture of alfalfa plant. 1. Nodule weight in the field was reduced 30% after the first cutting and 25% after the second cutting, but during the following 30 days after second cutting, there was no significant difference between cutting and uncutting plots. 2. Specific nodule activities of cutting plots at the beginning of June and at the beginning of September were 80% and loo%, higher than those of uncutting plots respectively. Total nodule activities of cutting plots in late August and early September were 40% higher than those of uncutting plot. The decrease of nodule activity can be prevented by cutting at flowering stage. 3. The decrease of nodules in solution culture when 50% of the shoot was cut, was as much as that when shoot was not cut or flower buds were removered. But when 90% of the shoot was cut, the number of the nodules were decreased more remarkably than the above treatments. New nodules, when 90% of the shoot was cut, were reformed slowly and did not grow fully until 15 days after cutting.