• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.4
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• pp.67-74
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• 2008

This study was carried out to select proper species for early stage replantation in cutting-slope area of the Baekdu Range roadside. In the cutting-slope area and upper forest area of the cutting-slope area, sample plots of 104 were selected and their vegetations and environmental factors were investigated. We found total 151 species in the 104 plots. The species of high frequency of Baekdu Range roadside were found in the order of Lespedeza bicolor, Festuca arundinacea, Eragrostis curvula, Pinus densiflora, Salix hulteni, Lespedeza cuneata, Erigeron annuus, Rubus crataegifolius, Spodiopogon sibiricus, etc. The dominancy of Festuca arundinacea, Eragrostis curvula, Lespedeza bicolor, Pinus densiflora, Salix hulteni, Spodiopogon sibiricus, Miscanthus sinensis, Lespedeza maximowiczii, Acer ginnala were 12.74%, 10.43%, 7.48%, 4.42%, 4.09%, 3.13%, 2.49%, 2.45%, 2.40% in the roadside cutting-slope, respectively. The importance value of Quercus mongolica, Lindera obtusiloba, Rhododendron mucronulatum, Lespedeza maximowiczii, Rhododendron schlippenbachii, Lespedeza bicolor, Quercus serrata, Rhus trichocarpa were 17.32%, 13.82%, 11.60%, 11.31%, 8.76%, 8.04%, 7.65%, 7.10% in shrub layer of the upper forest area, respectively. The species of Carex lanceolata, Spodiopogon sibiricus, Carex siderosticta, Miscanthus sinensis, Artemisia sp., Potentilla fragarioides var. major, Astilbe chinensis var. davidii, Chrysanthemum zawadskii var. latilobum, Aster scaber, Lysimachia clethroides, Patrinia villosa, Lindera obtusiloba, Rhododendron mucronulatum, Rhododendron schlippenbachii, Rhus trichocarpa, Stephanandra incisa, Zanthoxylum schinifolium, Lespedeza sp., Lespedeza cuneata, Amorpha fruticosa, Ligustrum obtusifolium, and Weigela subsessilis, may be more helpful in stabilizing of the cutting-slope area and making harmony with the surrounding forest area.

• Journal of The Korean Society of Clinical Toxicology
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• v.4 no.2
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• pp.143-146
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• 2006

Historically, the common folk have made use of various wild herbs for both food and medicinal purposes. However, the misuse of these wild herbs can lead to adverse consequences, including severe poisoning in some cases. In cases of poisoning from wild herbs, patients can exhibit a variety of symptoms depending on the herbs involved, which in addition to gastrointestinal symptoms may include hemodynamic alteration and abnormal neurologic signs. In the present case, two patients were admitted to the emergency room with symptoms of toxicity after consuming Rhododendron brachycarpum liquor. Rhododendron brachycarpum and other wild herbs contain the toxic material grayanotoxin. Because of its serious toxic symptoms, great caution must be exercised in using rhododendrons for food and medicinal purposes.

• Journal of the Korean Institute of Landscape Architecture
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• v.17 no.2
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• pp.41-46
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• 1989

Rhododendron micranthum grown over the area of Kyoung Puck, Kang Weon Province is showy and very attractive evergreen broad-leaned shrub of shade resistance. This shrub is considered very useful for exploiting as a garden plant. Environments, growth characteristics and vegetation association in the wild habitat and in the garden planted with this shrub, were investigated to find out some appropriate means of propagation and cultivation of this shrub. The results thus obtained were stated as follows ; 1. Light intensity for the native habitat ranged in the proximity of 9%. The most abundant stand of this shrub occurred in the northen side of mountains, while still some plants were found in the eastern sides also. 2. Soil of the native habitat was acidic (pH 4.4) and infertility. 3. Average elevation of the native habitat was shown to be 230m above the sea level. 4. The plant of the native habitat showed an average of 3.9 new shoots per branch, whereas that of the garden planted (light intensity 100%) showed 1.2, 5% of an average was for sun-burn leaves were noted, while garden Plants(light intensity 100%) showed 90% of them. 5. Other tree species associated with Rhododendron micrathum in the native habitat were primarily Pinus densiflora and secondarily Sorbus alnifolia, hemerocallis aurautiaca, Rubus crataegifolius, and Salix hulteni. 6. Vegetation rate of plant habitats in the Rhododendron growing area was observed to be 0 to 80% involving 27 to 50 species of associated trees in the vegetation for the 10${\times}$10m quadrat area.

• Food Science and Preservation
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• v.13 no.4
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• pp.501-505
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• 2006

This study was carried out to investigate the antioxidative activity and cytotoxicity on human KB cell of extract from Rhododendron mucronulatum flower, and also to determine the contents of total polyphenol and flavonoid. The methanol extract of Rhododendron mucronulatum flower was fractionated with various solvents such as hexane, chloroform, ethyl acetate, butanol and water. The DPPH radical scavenging activities of ethyl acetate fraction had stronger activity than other fractions. So, antioxidative substances of ethyl acetate fraction were crude purified by silica gel column chromatography. The DPPH radical scavenging activities of crude purified fraction 2 and 3 were more than 90% at 40 ppm. In the presence of $100{\mu}g/mL$, growth inhibition on human KB cell by WST-1 assay showed 81.2% in chloroform fraction and 74.6% in hexane fraction. The contents of total polyphenol and flavonoid of ethyl acetate traction were 32.70% and 20.30%, respectively, The antioxidative activity showed correlation with total polyphenol and flavonoid contents.

• Journal of Forest and Environmental Science
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• v.29 no.2
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• pp.165-172
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• 2013

The habitats characteristics of Rhododendron micranthum Turcz. were investigated to compile basic data for conservation and restoration. Natural habitats were located at altitudes of 100-500 m with inclinations of $10-35^{\circ}$. Rhododendron micranthum population was classified into Pinus densiflora dominant population. In the study sites, soil organic matter, total nitrogen, available phosphate, exchangeable potassium, exchangeable sodium, exchangeable calcium, exchangeable magnesium, cation exchange capacity and soil pH were 4.10-8.64%, 0.18-0.46%, 8.69-26.70 $mgkg^{-1}$, 0.10-0.23 $cmol^+kg^{-1}$, 0.06-0.10 $cmol^+kg^{-1}$, 0.85-4.10 $cmol^+kg^{-1}$, 0.24-0.64 $cmol^+kg^{-1}$, 12.76-20.90 $cmol^+kg^{-1}$, 4.34-5.15. Rooting rate is too low, cutting propagation, breeding methods are not good. Also, this study was investigated seed germination of R. micranthum depends on soaking treatment. R. micranthum was soaked with tap water for four days, the average values of germination day were represented of 70%/1 week.

• The Korean Journal of Mycology
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• v.46 no.1
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• pp.69-74
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• 2018

The Rhododendron powdery mildew fungus Erysiphe izuensis has been recorded throughout Asia, including China, Japan, Korea, and Russia. In Korea, E. izuensis has been identified based on morphological characteristics of the anamorph found on introduced Rhododendron spp. We here describe the first identification of E. izuensis collected from Rhododendron yedoense f. poukhanense in Korea. Morphological characteristics of the teleomorph as well as internal transcribed spacer sequences of the species are provided. Moreover, we describe the characteristics of the primary conidia and conidial surface pattern of E. izuensis for the first time.

• FLOWER RESEARCH JOURNAL
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• v.17 no.2
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• pp.101-105
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• 2009

This study was conducted to investigate the effect of treatment time and concentration of a chemical pinching agent, dikegulac, on branches and growth of Rhododendron simsii 'California Sunset'. R. simsii 'California Sunset' developed lateral branches naturally but the number of them was few. Treatment of dikegulac delayed the terminal bud development, increased in size, the chlorophyll contents of the leaf, and the number of lateral branches in June. Especially, the number of lateral branches were better at $1,500mg{\cdot}L^{-1}$ dikegulac than the others. But growth in August of R. simsii 'California Sunset' was naturally lower than June, there was no effect of lateral branches by dikegulac.

• Journal of Forest and Environmental Science
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• v.34 no.6
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• pp.435-450
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• 2018

Phenological events of four Rhododendron tree species (viz. R. arboreum, R. arboreum ssp. delavayi var. delavayi, R. barbatum and R. kesangiae) was monitored in temperate mixed broad-leaved forests of Arunachal Pradesh, India. Phenological events like flower bud formation, flowering, fruit setting, fruit maturing, seed dispersal, leaf bud formation, leaf flushing, and leaf shedding were recorded. Indices i.e., phenophase sequence index (PSI), active phenophasic period of the species (APS) and index of reproductive/vegetative activity (RVA) were also calculated. Present study revealed that bark consistency, growth form and leaf pattern of the studied species have showed variations among the species. Rhododendron species exhibited the phenological events overlapping with other phenophases. The peak flower bud formation was observed during the winter; R. arboreum ssp. delavayi var. delavayi start flowering from December, while the flowering in rest three species exhibited during February to April. Fruit setting occurred during summer to autumn while fruit maturation revealed peak during November. Leaf bud formation illustrated two peaks in April and May, leaf flushing exhibited peak in June, while leaf shedding peaked during October to November. Active phenophasic period of the species were found 12 months, which revealed that species engage in various phenophase activities throughout the year. Phenophase sequence index ranged between 0.8 to 0.9 (PSI ${\geq}0.6$), signifies that species have a sequential arrangement of phenophases. Index of reproductive/vegetative activity of the species exemplified >1, indicate that the reproductive phenophases were dominance over vegetative phenophases. The study have provided substantial insight on the life cycle events of Rhododendron species and ecological approaches for further scientific study with recent climate change and effective management and conservation.

• Korean Journal of Environment and Ecology
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• v.28 no.6
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• pp.751-761
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• 2014

This study was carried out to analyze the vegetation properties, soil characteristics and ordination of Rhododendron brachycarpum population in South Korea. Rhododendron brachycarpum were mainly distributed along the Ulleungdo and Baekdudaegan of the Korean penninsula and it's population was located at an elevation of 872m to 1466m. The Rhododendron brachycarpum population was classified into Taxus cuspidata var. latifolia dominant population, Magnolia sieboldii dominant population, Thuja koraiensis dominant population and Rhododendron brachycarpum typical population. The composition of soil properties in the same areas are as follows: organic matter, total nitrogen, available phosphorous, exchangeable $K^+$, exchangeable $Ca^{2+}$, exchangeable $Mg^{2+}$ contained, and soil pH. The capacities of these chemical properties of the soil ranged from 10.45~15.28%, 0.37~0.61%, $0.21{\sim}0.35cmol^+/kg$, $0.39{\sim}2.54cmol^+/kg$, $0.17{\sim}0.50cmol^+/kg$, $18.28{\sim}22.81cmol^+/kg$ and 4.66~5.23 respectively. The results of the correlation between communities and soil conditions of vegetation of Rhododendron brachycarpum by DCCA ordination method are as follows: Taxus cuspidata var. latifolia dominant population was found in the very steep sloped area that has low percentage of total organic matter and nitrogen than other populations. Magnolia sieboldii dominant population and Thuja koraiensis dominant population was found in the steep sloped area that has high percentage of total organic matter and nitrogen than other populations. Thuja koraiensis dominant population was found in the gentle sloped area that has high percentage of altitudinal and rock exposure. Current status of Rhododendron brachycarpum is very vulnerable with a collection of herbs constantly threatening the species' survival. Thus, concrete conservation plans to protect natural habitats should be set up as soon as possible.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.6
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• pp.52-62
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• 2006

The flora of vascular plants around Chunji and Sochunji in Mt. Baekdu was listed 120 taxa; 31 families, 81 genera, 97 species, 1 subspecies, 21 varieties and 1 form. About endangered wild plants, 2 taxa (Paeonia obovata, Rhododendron aureum) are in class II. 12 taxa were listed as rare and endangered plants; Disporum ovale, Lilium davuricum, Saxifraga punctata, Rosa marretii, Cnidium tachiroei, Bupleurum euphorbioides, Halenia corniculata, Gentiana jamesii, Pedicularis verticillata, etc. 10 taxa were listed as Korean endemic plants; Lilium amabile, Aconitum pseudolaeve var. erectum, Oxytropis anertii for. alba, Valeriana officinalis var. latifolia, Cardamine resedifolia var. morii, Homopteryx nakaiana, Saussurea alpicola, Ligularia jamesii, etc. Specific plants by floral region were total 47 taxa; 3 taxa (Paeonia obovata, Rhododendron aureum, Pedicularis verticillata) in class V, 15 taxa (Lycopodium annotinum, Alnus maximowiczii, Saxifraga punctata, Petasites saxatile, etc.) in class IV, 5 taxa (Spiraea salicifolia, Sanguisorba hakusanensis, Acer ukurunduense, Campanula glomerata var. dahurica, Cacalia adenostyloides) in class III, 18 taxa (Lycopodium chinense, Disporum ovale, Ceologlossum viride var. bracteatum, Betula ermani, Aruncus dioicus var. kamtschaticus, Filipendula multijuga, Geranium eriostemon, Cnidium tachiroei, Ligularia stenocephala, etc.) in class II, 6 taxa (Pinus koraiensis, Cimicifuga simplex, Sanguisorba tenuifolia var. alba, Senecio nemorensis, Cacalia hastata subsp. orientalis, Cirsium pendulum) in class I. Peculiar flora around Chunji is thought to be made by the environmental factors such as wind, temperature and rainfall that influence the plants' growth.