• Journal of the Korean Institute of Landscape Architecture
• /
• v.29 no.4
• /
• pp.82-90
• /
• 2001

This study was carried out to reveal optimum conditions for in vitro propagation of 3 Korean native azalea species, Rhododendron mucronulatum, R. yedonese var. poukhanense, and R. shlippenbachii, which are useful for landscape proposes. Seeds and meristems from three azalea species were cultured on 1/2MS, Hyponex, and Anderson media containing growth of regulators benzyladenine(BA) and 2-isopentenyadenosine(2ip). The results were as follows. 1. In the culture of R. schlippenbachii and R. mucronulatum seeds, in vitro seedlings germinated and grew well on he 1/2MS and Anderson media, while R. yedoense var. poukhanense on Hyponex media containing 6.0mg/$\ell$ 2ip. 2. When the meristems of R. mucronulatum were cultured on Andeson media containing 9.0mg/$\ell$ 2ip, the survival rate of meristems was 23.0% in 6 weeks after culture, and the survival rate of R. schlippenbachii was 46.0% o nthe same media containing 12.0mg/$\ell$ 2ip. The survial rate of R. yedoense var. poukhanense was 92.0% onHyponex media containing 0.5mg/$\ell$ BA and 9.0mg/$\ell$ 2ip. When the meristems of R. mucronulatum and R. yedoense var. poukhanense were cultured on Hyponex media containing 12.0mg/$\ell$ 2ip, they showed the most excellent growth. R. schlippenbachii grew well on Anderson media containing 9.0mg/$\ell$ 2ip. When in vitro shoots of R. yedoense var. poukhanense were subcultured to solid medium, they grew well in shoot growth on Hyponex media containing 6.0mg/$\ell$ 2ip.

• Journal of Plant Biology
• /
• v.26 no.1
• /
• pp.33-39
• /
• 1983

Twigs bearing floral buds of Rhododendron yedoense var. poukhanense(Ryp) and R. sinmsii(Rs), hardy species in Korea, were used to investigate the cold hardiness in relation to the developmental and anatomical characteristics, and the changes of water content. In floral buds of both species, the reproductive organs, pistils and stamens, matured within the bud scales in early ctober to prepare for a cold acclimation. The ray parenchymatous areas occupied in xylem were 41% in Ryp and 38% Rs. As the storage temperature is raised from 2 to 17$^{\circ}C$, water content increased more highly in Rs than in Ryp. Exotherm temperature of floral bud in Ryp was generally lower than that in Rs. The result supports that the higher cold-hardiness is achieved owing to the earlier maturation of floral buds, to the larger area of ray parenchyma in xylem, and to the lesser increase of water content as the storage temperature is raised.

• Journal of Environmental Science International
• /
• v.20 no.4
• /
• pp.427-434
• /
• 2011

This study characterized the full range of vegetation in a upland wetland (marshland) in Korea. Classified community types were used to describe vegetation at the marshland and adjacent areas. The communities contained 44 species of vascular plants and all species were identified into four plant community types. The Rhododendron yedoense f. poukhanense type and Lespedeza cyrtobotrya type had a high representation infacultative upland species (FU) and obligate upland species (OU), respectively. The monocot type was dominant in marshland by Miscanthuns saccharifloruc and contained 14 species. Together the three areas contained four species, with the strongest indicator species being Ranunculus acris var. nipponicus, Rhododendron yedoense f. poukhanense, Hemerocallis fulva, and Miscanthuns sinensis var. purpurascens. Shannon-Weaver index of diversity also varied among the community types (F = 18.9, df = 2), with the types FU having significantly higher value (3.467) than the others (1.125 for type FW and 1.239 for type OU).

• Proceedings of the PSK Conference
• /
• 2000.10a
• /
• pp.220.1-220.1
• /
• 2000

• Applied Biological Chemistry
• /
• v.46 no.2
• /
• pp.144-149
• /
• 2003

Extracts were obtained from the flower of Rhododendro yedoense var. poukhanense. (7 kg) in 80% aqueous MeOH and successively fractionated with solvent of EtOAc, n-BuOH and $H_2O$, successively. Silica gel and ODS column chromatographies of the EtOAc and n-BuOH fractions were repeatedly carried out by using the various solvent systems to give five terpenoids. Chemical structures of the isolated terpenoids were determined as $2{\alpha},3{\beta}-dihydroxylolean-12-ene$ (1), ursolic acid (2), grayanotoxin IV (3), grayanotoxin I (4) and grayanotoxin III (5) based on the interpretation of several spectral data including 2D-NMR such as $^1H-^1H\;COSY$, HMQC and HMBC.

• Proceedings of the PSK Conference
• /
• 2000.04a
• /
• pp.172.3-173
• /
• 2000

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.2 no.4
• /
• pp.47-53
• /
• 1999

In order to elucidate physiological factors involved in causing the winter injuries of evergreen Japanese rhododendron (Rhododendron obtusum cv. Hinodegiri) and semi-evergreen rhododendron (Rhododendron yedoense var. poukhanense), these studies were conducted from late winter to early spring. The results were summarized as follows; The water potential, water content in stem, water potential and content have continuously increased in both species between February and May. In R. yedoense, shading treatment had 0.3MPa upper water potential and 3% upper water content than the control. Rhododendron obtusum, the treatments with shading had 0.9MPa upper water potential and 11% upper water content that the control. The difference of water balance by treatments could be found in vitality of stem measured by TTC test. Especially R. obtusum in the treatments with shading in has higher vitality than the control. we find that winter damage of evergreen R. obtusum was determined by whether water balance could be recovered from water deficient state during the dehardening period, or not. In order to recover of the water balance, decreasing water loss more important than increasing water supply, and that was effectively acrueved by the treatment with shading.

• The Korean Journal of Ecology
• /
• v.22 no.6
• /
• pp.325-335
• /
• 1999

Empetrum nigrum dominant community or Rhododendron mucronulatum and R. yedoense var. poukhanense dominant shrub community are developing above l,500m on Mt. Halla in Cheju Island, Korea. These communities were formed as a result of the forest of Abies koreana regression by grazing or erosion over a long period of time. This study was conducted using the phytosociological method and it clarified the floristic composition of the community in Cheju Island by comparing with a similar community in Japan. Also this study interpreted the development data of these communities and considered community succession. As a result of our interpretation, shrub community of Cheju Island is recognized as two associations, Festuco obinae-Empetretum nigrum ass. nov and Rhododendretum mucronulatum ass. nov. Each association of Cheju Island is composed of endemic species of Cheju Island. related to the Korean peninsula and to Japan. The two associations are divided into 8 sub-units but each community development has been created with longtime grazing and prescribed fire. Maybe the location stability by stoppage of interference and grazing will process community transition Quickly. Comparing the shrub communities of Cheju Island with Maianthemo-Rhododendretum in Kyushu, Japan, which is close geographically, both areas have the species of Miscanthetea sinesis and Ericaceae in common. But Cheju Island has more abundant species and has higher ratio of appearance of alpine plants. The shrub communities of Cheju Island and Kyushu. Japan are identified as having a different rank over Alliance.

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

• The Korean Journal of Mycology
• /
• v.48 no.3
• /
• pp.329-335
• /
• 2020

From 2008 to 2017, Korean azalea (Rhododendron yedoense f. poukhanense) showing angular, necrotic leaf spots were found in Jeju and Hongcheon, Korea. The lesions occurred frequently, detracting from the beauty of the glossy green leaves of the plant and causing premature defoliation. Therefore, to identify the fungus associated with the lesions, morphological characterization and molecular phylogenetic analysis of actin (Act), translation elongation factor 1-alpha (EF), internal transcribed spacer (ITS), 28S nrDNA (LSU), and RNA polymerase II encoding the second largest subunit (RPB2) of the two representative isolates were performed. The phylogenetic tree inferred from the neighbor-joining method showed the isolates clustering in the Sphaerulina azaleae group. Therefore, the fungus associated with the angular leaf spots on the Korean azalea was identified as Sphaerulina azaleae.