• Korean Journal of Plant Taxonomy
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• v.36 no.3
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• pp.163-187
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• 2006

Taxonomic studies were conducted to evaluate the interspecific relationships in Viola albida var. albida and its related taxa using seven populations for morphology, palynology and anatomy. Molecular phylogenetic studies were also examined in 28 populations including 19 Korean, four Chinese, two Japanese, one American population and two outgroups using nrITS, and 27 populations except V pinnata for trnL-F region of chloroplast DNA. Morphological differences was observed among seven populations of three species in leaf shape, but characters such as serrate number of leaf margins, petal size, pistil shape were showed overlap between populations. Pollen shape of seven populations was monad and grain shape on the polar axis was semi-angular. Morphology of aperture was tri-colporate, and the surface sculpturing was scabrate in rugulate. The grain shape of equatorial view of five populations was prolate whereas V albida var. taknhashii type 1 and V albida var. chaerophylloides type 3 were subprolate. The anatomical characters of rnidvein of leaf, petiole, peduncle, root were also described for the species. The stomatal apparatus of the leaves was observed only in abaxial surface, and the number of stoma per unit ($mm^2$) were abundant in incised than lobate or cleft margin of the leaves. The nrITS analysis shows that V. pinnata and V. dissecta was monophyletic and occupied a basal position in the V. albida var. albida and its related taxa. The other clade including infraspecific populations of V. albida, and V. eizanensis was paraphyletic. The trnL-F noncoding region analysis was similar to the ITS tree. According to the above observations in morphology, palynology, anatomy, and molecular phylogenetic analysis, the significant differences were not found except for leaf shape in Viola albida var. albida and its related taxa, therefore V. albida var. takanhashii and V. albida var. chaerophylloides were considered to be an infraspecific taxa of V. albida var. albida rather than an independent species, subvariety or variety of V. pinnata and V. dissecta.

• Korean Journal of Plant Taxonomy
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• v.46 no.2
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• pp.256-266
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• 2016

A total of 13,000 individuals of Dendrobium moniliforme (L.) Sw. artificially propagated in laboratories and greenhouses were restored in their natural habitat of Bogildo Island, Wandogun, in the southern part of Korea in June of 2013. The growing conditions of the individuals were monitored for two years. The parental individuals for the restoration were obtained from a wild population in southern Korea, from which seeds were produced via artificial crossings. These seeds were germinated and cultivated in growing media and two-year-old plants were then grown in greenhouse beds. The genetic diversity among the propagated individuals was confirmed by examining DNA sequences of five regions of the chloroplast genome and the nuclear ITS region. The diversity values were as high as the average values of natural populations. All propagated individuals were transplanted into two different sites on Bogildo by research teams with local residents and national park rangers. After restoration, we counted and measured the surviving individuals, vegetative propagated stems, and growth rates in June of both 2014 and 2015. There was no human interference, and 97% of the individuals survived. The number of propagules increased by 227% in two years. In contrast, the average length of the stems decreased during the period. In addition, different survival and propagation rates were recorded depending on the host plants and the restored sites. The shaded sides of rock cliffs and the bark of Quercus salicina showed the best propagation rates, followed by the bark of Camellia japonica. A few individuals of D. moniliforme successfully flowered, pollinated, and fruited after restoration. Overall, our monitoring data over two years indicate that the restored individuals were well adapted and vigorously propagated at the restored sites. In order to prevent human disturbance of the restored sites, a CCTV monitoring system powered by a solar panel was installed after the restoration. In addition, a human surveillance system is operated by national park rangers with local residents.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.1-9
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• 2006

Peroxiredoxins (Prxs) are ubiquitously distributed and play important functions in diverse cellular signaling systems. The proteins are largely classified into three groups, such as typical 2-Cys Prx, atypical 2-Cys Prx, and 1-Cys Prx, that are distinguished by their catalytic mechanisms and number of Cys residues. From the three classes of Prxs, the typical 2-Cys Prx containing the two-conserved Cys residues at its N-terminus and C-terminus catalyzes $H_2O_2$ with the use of thioredoxin (Trx) as an electron donor. During the catalytic cycle, the N-terminal Cys residue undergoes a peroxide-dependent oxidation to sulfenic acid, which can be further oxidized to sulfinic acid at the presence of high concentrations of $H_2O_2$ and a Trx system containing Trx, Trx reductase, and NADPH. The sulfinic acid form of 2-Cys Prx is reduced by the action of sulfiredoxin which requires ATP as an energy source. Under the strong oxidative or heat shock stress conditions, 2-Cys Prx in eukaryotes rapidly switches its protein structure from low-molecular-weight species to high-molecular-weight protein structures. In accordance with its structural changes, the protein concomitantly triggers functional switching from a peroxidase to a molecular chaperone, which can protect its substrate denaturation from external stress. In addition to its N-terminal active site, the C-terminal domain including 'YF-motif' of 2-Cys Prx plays a critical role in the structural changes. Therefore, the C-terminal truncated 2-Cys Prxs are not able to regulate their protein structures and highly resistant to $H_2O_2$-dependent hyperoxidation, suggesting that the reaction is guided by the peroxidatic Cys residue. Based on the results, it may be concluded that the peroxidatic Cys of 2-Cys Prx acts as an '$H_2O_2$-sensor' in the cells. The oxidative stress-dependent regulation of 2-Cys Prx provides a means of defense systems in cells to adapt stress conditions by activating intracellular defense signaling pathways. Particularly, 2-Cys Prxs in plants are localized in chloroplasts with a dynamic protein structure. The protein undergoes conformational changes again oxidative stress. Depending on a redox-potential of the chloroplasts, the plant 2-Cys Prx forms super-molecular weight protein structures, which attach to the thylakoid membranes in a reversible manner.