Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Jongduk Jung is active.

Publication


Featured researches published by Jongduk Jung.


Journal of Plant Biology | 2008

Anatomical patterns of aerenchyma in aquatic and wetland plants

Jongduk Jung; Seung Cho Lee; Hong-Keun Choi

A well-developed aerenchyma is a major characteristic of aquatic plants. However, because such tissues are also found in wetland and terrestrial plants, it is not always possible to use their presence or absence to distinguish aquatic species. Whereas patterns of aerenchyma in roots have been studied in detail, those of the shoots have not. We collected and tested 110 species of various aquatic and wetland plants, including ferns (5), basal angiosperms (5), monocots (65), and eudicots (35). Three common and two rare types of aerenchyma were observed in their roots (three schizogeny and two lysigeny), plus five types of schizogeny in their shoots. We re-confirmed that, although a well-developed aerenchyma is more common in most organs of aquatic plants than in wetland plants, this presence cannot be used as strict evidence for the aquatic quality of vascular plants. Here, aerenchyma patterns were stable at the genus level, and the consistency of pattern was stronger in the roots than in the shoots. Furthermore, significant trends were verified in several higher taxa, and those consistencies of patterns partially coincided with their phylogeny.


Journal of Plant Biology | 2010

Systematic Rearrangement of Korean Scirpus L. s.l. (Cyperaceae) as Inferred from Nuclear ITS and Chloroplast rbcL Sequences

Jongduk Jung; Hong-Keun Choi

The genus Scirpus L. s.l. (Cyperaceae) has been accepted as a polyphyletic taxon by most plant taxonomists. This genus was separated into different genera by several different authors: Scirpus s. str., Trichophorum Pers., Bolboschoenus (Asch.) Palla, Schoenoplectus (Rchb.) Palla, and Schoenoplectiella Lye. The heterogeneity of Korean Scirpus s.l. has not yet been studied. We examined 17 taxa of Korean Scirpus s.l. by morphological characters and phylogenetic analyses based on nuclear ITS and chloroplast rbcL sequences. Phylogenetic analyses using maximum parsimony, maximum likelihood, and Bayesian method provided sufficient resolution. The phylogeny revealed the polyphyly of Korean Scirpus s.l. with five distinct clades. These clades correspond to Bolboschoenus, Schoenoplectus s.str., and Schoenoplectiella, Scirpus s.str., and Trichophorum, respectively. These five genera were delimited in terms of the morphology of tuber, bract, and inflorescence. By virtue of our findings, we suggest that the 17 taxa of Korean Scirpus s.l. should be placed into five genera as follows: Bolboschoenus (two species), Schoenoplectus (three species), Schoenoplectiella (six species), Scirpus s.str. (five species), and Trichophorum (one species).


Journal of Plant Biology | 2008

Two new species ofIsoetes (Isoetaceae) from Jeju Island, South Korea

Hong Keun Choi; Jongduk Jung; Changkyun Kim

We name and describe two new species,Isoetes jejuensis and I.hallasanensis, from Jeju Island, South Korea. These taxa are compared with related species in East Asia, including I.coreana andI. sinensis. The rugulate megaspore ornamentation ofI. jejuensis differs from those otherIsoetes species. Furthermore,I. hallasanensis varies fromI. asiatica in its microspore ornamentation and chromosome number, although both species have an echinate megaspore ornamentation. These new species are tetraploid (2n = 44), whereasI. coreana is hexaploid (2n = 66).


Journal of Plant Biology | 2011

Taxonomic Study of Korean Scirpus L. s.l. (Cyperaceae) II: Pattern of Phenotypic Evolution Inferred from Molecular Phylogeny

Jongduk Jung; Hong-Keun Choi

Scirpus L. s.l. is well known as one of the polyphyletic groups in Cyperaceae. Recent molecular phylogenetic studies clearly suggested that Scirpus s.l. should be separated into several independent genera. In this study, we intend to present the morphological variations and patterns of phenotypic evolution based on molecular phylogeny of Korean Scirpus s.l. Five genera, including 21 taxa from Korean Scirpus s.l., were examined: three species of Bolboschoenus, three species of Schoenoplectus, eight species of Schoenoplectiella including one hybrid, five species of Scirpus, and two species of Trichophorum. For morphological analyses, 23 and 48 characters were selected from vegetative and reproductive organs, respectively. Molecular phylogeny was inferred from a nuclear ribosomal internal transcribed spacer, the chloroplast rbcL gene, and the chloroplast trnL-F region. Distinct characteristics and quantitative variation was presented for identification of the five genera and their species. A pronounced pattern of morphological character change was reduction, although many other character states seem to be homoplastic. We suggest that the reduction of phenotypic characteristics has been expressed in terms of condensation of internodes, reduction of leaf blade, and simplification of inflorescence among five genera of Korean Scirpus s.l.


Systematic Botany | 2016

Specimens at the Center: An Informatics Workflow and Toolkit for Specimen-Level Analysis of Public DNA Database Data

Kasey K. Pham; Marlene Hahn; Kate Lueders; Bethany H. Brown; Leo P. Bruederle; Jeremy J. Bruhl; Kyong Sook Chung; Nathan J. Derieg; Marcial Escudero; Bruce A. Ford; Sebastian Gebauer; Berit Gehrke; Matthias H. Hoffmann; Takuji Hoshino; Pedro Jiménez-Mejías; Jongduk Jung; Sangtae Kim; Modesto Luceño; Enrique Maguilla; Santiago Martín-Bravo; Robert F. C. Naczi; Anton A. Reznicek; Eric H. Roalson; David Simpson; Julian R. Starr; Tamara Villaverde; Marcia J. Waterway; Karen L. Wilson; Okihito Yano; Shuren Zhang

Abstract Major public DNA databases — NCBI GenBank, the DNA DataBank of Japan (DDBJ), and the European Molecular Biology Laboratory (EMBL) — are invaluable biodiversity libraries. Systematists and other biodiversity scientists commonly mine these databases for sequence data to use in phylogenetic studies, but such studies generally use only the taxonomic identity of the sequenced tissue, not the specimen identity. Thus studies that use DNA supermatrices to construct phylogenetic trees with species at the tips typically do not take advantage of the fact that for many individuals in the public DNA databases, several DNA regions have been sampled; and for many species, two or more individuals have been sampled. Thus these studies typically do not make full use of the multigene datasets in public DNA databases to test species coherence and select optimal sequences to represent a species. In this study, we introduce a set of tools developed in the R programming language to construct individual-based trees from NCBI GenBank data and present a set of trees for the genus Carex (Cyperaceae) constructed using these methods. For the more than 770 species for which we found sequence data, our approach recovered an average of 1.85 gene regions per specimen, up to seven for some specimens, and more than 450 species represented by two or more specimens. Depending on the subset of genes analyzed, we found up to 42% of species monophyletic. We introduce a simple tree statistic—the Taxonomic Disparity Index (TDI)—to assist in curating specimen-level datasets and provide code for selecting maximally informative (or, conversely, minimally misleading) sequences as species exemplars. While tailored to the Carex dataset, the approach and code presented in this paper can readily be generalized to constructing individual-level trees from large amounts of data for any species group.


Journal of Ecology and Environment | 2012

Determination of the minimum population size for ex situ conservation of water-shield ( Brasenia schreberi J.F. Gmelin) inferred from AFLP analysis

Changkyun Kim; Hye Ryun Na; Jongduk Jung; Hojoon Kim; Jin-Oh Hyun; Hong-Keun Choi

Determination of the minimum population size is an important component for the ex situ conservation of an endangered species. Here, we present the identification of collection strategies that most efficiently captured the genetic diversity of Brasenia schreberi J.F. Gmelin (water-shield) in natural populations from the mainland (MGC) and Jeju Island (JNS) of South Korea, using amplified fragment length polymorphism (AFLP) markers. A total of 313 and 383 polymorphic bands were detected in the MGC and JNS populations, respectively. All of the 140 sampled ramets were distinguishable by the presence of distinct AFLP phenotypes. According to the simulation of the individual sampling by maximization sampling, 25 and 28 individuals captured all of the genetic diversity in the MGC population (mainland of South Korea) and the JNS population (Jeju Island), respectively. The level of genetic diversity of the core collections was similar to the entire collection, indicating that the core collections very well represent the diversity of the entire collection. We therefore suggest a management unit of B. schreberi based on the genetic information for assessing the minimum population size for its ex situ conservation.


Novon | 2010

A New Endemic Species in Trichophorum (Cyperaceae) from South Korea

Jongduk Jung; Hong-Keun Choi

Abstract Trichophorum dioicum J. Jung & H. K. Choi (Cyperaceae) was observed growing on limestone cliffs within a government-protected area, from Gangwon-do, South Korea. Morphological characteristics of the new species, such as the reduced leaf blade and the single spikelet at the culm terminus, correspond to Trichophorum Pers., a sister genus among Scirpus L. s.l. Previous molecular analysis of the chloroplast rbcL gene and ITS region of nuclear ribosomal DNA supported the identity of this new endemic species as a member of Trichophorum.


Journal of Plant Research | 2013

Recognition of two major clades and early diverged groups within the subfamily Cyperoideae (Cyperaceae) including Korean sedges

Jongduk Jung; Hong-Keun Choi


Journal of Plant Biology | 2012

Population Genetic Structure of the Endangered Brasenia schreberi in South Korea Based on Nuclear Ribosomal Spacer and Chloroplast DNA Sequences

Changkyun Kim; Jongduk Jung; Hye Ryun Na; Suk Weon Kim; Wei Li; Yasuro Kadono; Hyunchur Shin; Hong-Keun Choi


Plant Systematics and Evolution | 2012

Molecular identification of Schoenoplectiella species (Cyperaceae) by use of microsatellite markers

Changkyun Kim; Jongduk Jung; Hong-Keun Choi

Collaboration


Dive into the Jongduk Jung's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Eric H. Roalson

Washington State University

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge