• Korean Journal of Plant Taxonomy
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• v.45 no.2
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• pp.109-113
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• 2015

Fieldwork in Lao PDR during 2007-2008 resulted in the discovery of 15 unrecorded fern species among the flora of Lao PDR. All have been identified in other countries in southeastern Asia, as well as from other tropical areas. The species are as follows: Asplenicaceae (Asplenium delavayi, A. rockier), Athyriaceae (Anisocampium cuspidatum), Dennstaedtiaceae (Microlepia hookeriana, Pteridium revolutum), Dryopteridaceae (Didymochlaena truncatula, Dryopteris cochleata, Polystichum biaristatum, P. lindsaefolium), Gleicheniaceae (Dicranopteris curranii), Hypodematiaceae (Hypodematium crenatum), Lindsaeaceae (Lindsaea heterophylla), Pteridaceae (Pteris decrescens), Polypodiaceae (Pyrrosia nummularifolia) and Thelypteridaceae (Cyclosorus dentatus).

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.228-230
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• 1994

A Spotter ion Plating(SIP) system with a r. f. coil electrode and the Facing Target Sputter(FTS) source was designed for high-quality thin film formation. The rf discharge was combined with DC facing target sputtering in order to enhance ionization degree of a sputtered atoms. The discharge voltage-discharge characteristics curves of a FTS source could be characterized by the fern of $I{\propto}V^n$ with n in the range of $8{\sim}12$. The energy of ions incident on the substrate depended on the sheath potential of DC biased substrate. The mean impact ion energy increased with negative bias voltage and rf power. The adhesive force of the TiN film formed was in the range of $30{\sim}50N$, and markedly influenced by substrate bias voltage.

• Korean Journal of Plant Taxonomy
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• v.50 no.4
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• pp.403-412
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• 2020

Colonies of three independent gametophytes (one that is filamentous and two that are ribbon-like) without sporophytes occur in Gyeonggi-do, Gangwon-do, Gyeongsang-do, and Jeju-do, Korea. They have a moss-like appearance at first sight, with tiny plantlets and gemmae, and grow in cool, shaded, relatively deep dint places of large rocks, such as the small caves in high mountains, close to valleys. The gametophytes were identified based on morphological and molecular data by chloroplast DNA (cpDNA) sequence data (rbcL, rps4 gene and rps4-trnS intergenic spacer). Here, rbcL, rps4 gene and rps4-trnS intergenic spacer data of one independent gametophyte distributed in Korea have the same morphology, DNA sequence and monophyletic group as Crepidomanes intricatum from the eastern United States. They also share the same cpDNA data with Crepidomanes schmidtianum recently reported from Korea. The other independent gametophyte should be Hymenophyllum wrightii based on cpDNA data. The last one was presumed to be Pleurosoriopsis makinoi based on molecular data. The taxonomic status was confirmed to be the forma of Hymenophyllum wrightii through a revision of Hymenophyllum wrightii f. serratum based on molecular data.

• The Plant Pathology Journal
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• v.27 no.4
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• pp.372-377
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• 2011

A virus causing mottle and stunt symptom on Zea mays was observed around Ulleng-do, Korea and identified as Cucumber mosaic virus (CMV-ZM) based upon biological, serological, and molecular characteristics. In host range studies, the CMV-ZM isolate produced local lesions on Datura stramonium, Vigna unguiculata, Cucurbita moschata, Chenopodium amaranticolor, Ch. quinoa, whereas this isolate produced systemic mosaic on Nicotiana tabacum cv. 'Xanthi-nc', Capsicum annuum, Solanum lycopersicum, Solanum melongena, Cucurbita pepo, and Z. mays. In addition, chlorotic local rings on inoculated leaves along with severe mosaic, malformation, and fern leaf symptoms on upper systemic leaves were shown in N. glutinosa plants. Complete nucleotide sequences of each genomic RNA segment was determined and compared to those of the other CMV strains. Comparison of the nucleotide sequence of 1a open reading frame (ORF) revealed approximately 89.2-92.4% sequence identity with each CMV subgroup IA and IB strain, while showing only 78% sequence identity with CMV subgroup II. Nucleotide sequence analysis of RNA2 ORFs revealed 85.3-97.6% sequence identity with subgroup I. In ORFs of RNA3, levels of nucleotide sequence identities were higher than 92-99.2% with CMV subgroup I and lower than 82% with CMV isolates of subgroup II. These results suggest that CMV-ZM isolate is more closely related to subgroup I than subgroup II and therefore, CMV-ZM isolate might be classified into as CMV subgroup I based on biological and molecular analysis.

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.462-471
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• 2017

Thiamine pyrophosphate (TPP), the active form of thiamine is a cofactor for enzymes involved in central metabolism pathways. However, it is also known to have a role as a stress signaling molecule in response to environmental changes. Anabaena sp. and N. oculata are microorganisms which are abundantly found in Malaysia's freshwater and marine ecosystem. However, not much studies have been done especially in regards to thiamine biosynthesis. This work aimed to amplify of gene transcripts coding for thiamine biosynthesis enzymes besides looking at the expression of thiamine biosynthesis genes upon stress application. Various stress inducers were applied to the cultures and RNA was extracted at different time points. The first two genes, ThiC and ThiG/Thi4 encoding enzymes of the pyrimidine and thiazole branch respectively in the thiamine biosynthesis pathway were identified and amplified. The expression of the genes were analysed via RT-PCR and the intensity of bands were analysed using ImageJ software. The results showed up to 4-fold increase in the expression of ThiC and ThiG gene transcript as compared to control sample in Anabaena sp. ThiC gene in N. oculata showed an expression of 6-fold higher as compared to control sample. In conclusion, stresses induced the expression of the gene coding for one of the most important enzymes in thiamine biosynthesis pathway. This is an agreement with the hypothesis that overexpression of thiamine is crucial in assisting plants to combat abiotic stresses.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.2
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• pp.161-167
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• 2004

Silkworms sex determination drew high attention from researchers. Sex chromosomes on the silkworm are of ZW type for females and ZZ type for males. Chromosome W plays an important role in sex determination. Although several molecular linkage maps have been constructed for silkworm, very few markers are discovered on the W chromosome. In order to look for molecular markers and to further locate the Fern gene on chromosome W, we used genomic DNA from both female and male larvae of a silkworm strain named 937 as PCR templates for RAPD amplification with 200 arbitrary 10-mer primers. The amplification results showed three female-specific bands, namely ${OPG-07_496}, {OPC-15_1,660} and {OPE-18_1,279}$. Further verification, however, revealed no band from OPG-07 and OPC-15 in either sex in the strain 798, but OPE-18 provided female-specific band in the strains Suluan7 and C108, and absent in both males and strain 798. This indicates that the bands from ${OPG-07_496} and {OPC-15_1,660}$ are probably female-specific in strain 937, and the band from OPE-18 was probably amplified from a common segment shared by most strains. The genomic DNAs from OPG-07 and OPC-15 were cloned and sequenced. Sequence analysis showed that the DNAs from OPG-07 and OPC-15 have high identities with the retrotransposable elements, and DNA from OPC-15 contains a portion of sequence which probably encodes an eukaryotic translation initiation factor 4E binding protein (eIF4EBP).

• The Plant Pathology Journal
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• v.26 no.1
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• pp.93-98
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• 2010

A virus isolate causing symptoms of yellow mosaic, fern leaves, malformation and plant necrosis on Rudbeckia bicolor was prevalent around Pyeongchang area in Korea. The causal virus was identified as Cucumber mosaic virus (CMV) using characteristics from biological, serological and molecular analyses and named as CMV-Rb. CMV-Rb caused mosaic on Nicotiana benthamiana, N. tabacum, Capsicum annuum, and Lycopersicon esculentum. However, typical local lesions did not develop on inoculated Pisum sativum, Cucurbita moschata, Datura stramonium and Tetragonia expansa plants. Full-length genome sequences of CMV-Rb RNAs 1, 2 and 3 were obtained using 12 primer pairs by RT-PCR analysis. The genome of CMV-Rb RNA segments 1, 2, and 3 consists of 3363nt, 3049nt, and 2214nt in length, respectively. In order to ascertain their taxonomic identity, nucleotide and the deduced amino acid sequence analyses RNAs 1, 2 and 3 of CMV-Rb isolates were conducted with previously reported sequences of CMV strains and/or isolates. CMV-Rb RNAs showed about 90 to 99% sequence identity to those of subgroup I strains suggesting that CMV-Rb is more closely related to CMV isolates belong to subgroup I. To our knowledge, this is the first report of CMV on Rudbeckia bicolor in Korea.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.142-148
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• 2014

Effect of silicon (Si) nutrition on growth and temperature stress tolerance of Nephrolepis exaltata 'Corditas' grown in a soilless substrate was examined. In vitro-grown acclimatized plantlets were transplanted into the pots containing a coir-based substrate. A nutrient solution containing 0, 50, or $100mg{\cdot}L^{-1}$ Si was supplied through a drip-irrigation system. After 5 months of cultiv ation, S i-treated and -untreated p lants were grown at 10, 25, or $40{\pm}1^{\circ}C$ under a 12 h photoperiod with $530{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and 60% RH. After 7 days, chlorophyll content and chlorophyll fluorescence parameters were measured. Silicon nutrition had a negative effect on growth characteristics of N. exaltata 'Corditas'. However, Si-treated plants had more tolerance to temperature stress than the control plants. The Fv/Fm value was not significantly different when the plants were exposed to $25^{\circ}C$. However, significant difference in Fv/Fm was recorded when plants were exposed to 10 or $40^{\circ}C$. Thus, Fv/Fm could be used as an indicator of low and high temperature tolerance in ferns. The present study also suggests that application of Si may be used to enhance temperature tolerance of ferns.

• Weed & Turfgrass Science
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• v.6 no.1
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• pp.61-66
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• 2017

The appropriate level of irrigation for turfgrasses is vital to the performance of the turfgrass as well as conservation of water. Linear gradient irrigation system (LGIS) facilitates long-term study of turf performance under continuous irrigation gradients at extreme ends of the irrigation scale. The objectives of this study were to: a) determine the minimum irrigation requirements and relative drought resistance in three warm season turfgrasses; and b) evaluate the medium to long-term effects of irrigation levels on turf persistence, weed invasion, and susceptibility to diseases. Results suggest that grasses differed in drought resistance and persistence under variable irrigation regimes. Irrigation (Ep) required for consistent acceptable turf quality for respective grasses was Cynodon dactylon x C. transvaalensis (61%), Zoysia matrella L. Merr (73%), and Stenotaphrum secundatum 'Palmetto' (86%). Brown patch infection was most prevalent in Stenotaphrum secundatum 'Palmetto' at 12 and 125% Ep irrigation. Cynodon dactylon x C. transvaalensis and Zoysia matrella L. Merr were better able to adapt to the various irrigation regimes, and this ability allowed these species to resist drought, and maintain turf coverage which in turn, kept weeds and the occurrence of diseases at bay. Ranking these grasses for their drought tolerance abilities showed that Cynodon dactylon x C. transvaalensis had the most outstanding resistance against drought, followed by Zoysia matrella L. Merr, and lastly, Stenotaphrum secundatum 'Palmetto'. Despite having the highest irrigation requirement, Stenotaphrum secundatum 'Palmetto' was still not able to maintain persistence at high irrigation regimes. Likewise, this grass also lost turf coverage at low irrigation levels.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.348-354
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• 2006

Homogenized prothallus of 6 species (Cyrtomium falcatum, Cyrtomium caryoptideum var. coreanum, Dryopteris varia, Asplenium incisum, Camptosous sibiricus and Phyllitis scolopendrium) were treated with gamma radiation or by chemical mutagenesis with EMS, NMU, $NaN_3$ and colchicine to assess their sensitivities for each treatments and also with the aim of inducing mutations. Generally, decrease of proliferation ratio was dose-dependent and time-dependent. Based on proliferation ratio, optimum dose of gamma irradiation was $5{\sim}10krad$ except in D. varia with 20krad. Optimum condition of EMS treatment was considered as 50mM for 3h and for NMU as $5{\sim}10mM\;for\;1{\sim}3h$. Optimum condition of $NaN_3$ treatment was considered as $0.5{\sim}1mM\;for\;1{\sim}3h$. For colchicine, there were significant differences between species as to the proliferation ratios of prothallus for each treatment.