• Korean Journal of Plant Resources
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• v.28 no.5
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• pp.656-664
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• 2015

To produce high quality watermelon, three tetraploid watermelon breeding lines (‘SA03-1’, ‘SA06-1’ and ‘SB01-1’) were developed by treatment with different chromosome doubling reagents. To identify the optimal tetraploid inductive conditions, the three watermelon breeding lines were selected by counting the number of doubled chloroplasts in guard cells. Tetraploid induction rates differed depending on the genotypes and treatment with doubling reagents. However, the highest induction rate occurred with 1.0% colchicine (82.2%). These putative tetraploid lines were re-confirmed for ploidy using flow cytometric analysis and chromosome counting. The internode length of the tetraploid breeding lines was different when the leaf size was larger in all three tetraploid lines compared to their diploids. The fruit weight of the tetraploid fruits for ‘SA03-1’ and ‘SB01-1’ was lower than for their diploid, and the rind thickness and total sugar content (°Brix) of tetraploid SB01-1 were significantly different from those of its diploid. Tetraploid lines were sterile, yielded a lower number of seeds per fruit for ‘SA03-1’ (21), ‘SA06-1’ (62), and ‘SB01-1’ (34.7), and the seeds were larger and thicker than those of their diploids. These tetraploid breeding results will be useful for breeding new seedless watermelon cultivars.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.88-96
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• 2005

Paraquat-resistant biotype of Conyza canadensis (L.) Cronq. was determined by chlorophyll loss and random amplified polymorphic DNA (RAPD) analysis and the resistant mechanism was investigated with respect to absorption, translocation, and binding constant. RAPD analysis for paraquat resistant (R) and susceptible (S) biotypes found in a pear orchard revealed that the biotypes possessed remote genetic relationship. Chlorophyll loss, as an indication of paraquat toxicity, of S biotype was 7.8-fold greater than that of R biotype. There were no differences in contents of epicuticular wax and cuticle and amounts of [14C]paraquat penetrating the cuticle between the two biotypes. Little translocation of the herbicide out of the treated leaf was observed in either biotype. Binding constants of paraquat to the cell wall and thylakoid membrane were 7.4-fold and 16.9-fold, respectively, higher in R biotype than in S biotype. The results suggest that the resistance mechanism of C. canadensis biotype is due partly to high binding affinity of paraquat to the cell wall and thylakoid membrane.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.97-103
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• 2005

Antioxidative responses of transgenic tobacco plants expressing both superoxide dismutase (SOD) and ascorbate peroxidase (APX) in chloroplasts was investigated with several herbicides. In greenhouse test, tolerance of SOD/APX-overexpressed tobacco (CA) to photosystem (PS) I inhibitor paraquat was increased by about 40%. However, any response differences between CA and wild type (WT) tobacco was not observed in a treatment with PS II inhibitors (bromoxynil, diuron and bromacil), chlorophyll biosynthesis inhibitor(oxyfluorfen), carotenoid biosynthesis inhibitor (fluridone) and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase inhibitor (glyphosate). This tendency was also similar in the growth chamber test of low light intensity, using paraquat and diuron. That is, increased antioxidant activity of CA was shown only in paraquat treatment. When paraquat was foliar-treated to 6 to 9-leaf stage plant, the third to fourth placed leaf from shoot tip showed relatively higher antioxidant activity. Ascorbate supplemented to paraquat solution alleviated the phytotoxicity with a similar range in both CA and WT. In conclusion, CA specifically responded to oxidative stress induced by paraquat among tested herbicides in a whole plant assay.

• Korean Journal of Plant Taxonomy
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• v.41 no.4
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• pp.299-314
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• 2011

The choice of molecular markers is the first step when selecting experimental plans in the field of population genetics. The popular molecular markers in population genetic studies are mainly allozyme, RAPD, RFLP, AFLP, microsatellite, SNP and ISSR. Among these, microsatellites are frequently found in nuclear, chloroplast and mitochondrial genome, showing a high level of polymorphism and nuclear microsatellites are codominant. Thus, it is a favorable molecular marker for population structure analyses and genetic diversity studies. Microsatellites are composed of tandem repeated 1~6 base pair nucleotide motifs and can be easily amplified by PCR reactions using locus specific primers. Because microsatellites have low cross-species transferability, however, they are only applicable between phylogenetically close species. In wild plants, the lack of genomic information and the high development cost of the microsatellite obstruct the wider use of microsatellites in plant population genetics research. In this review, we introduce the basis for microsatellite markers, the development process, and analytical methods as well as evolutionary models and their applications. In addition, possible genotyping errors which lead to erroneous conclusions are discussed.

• Korean Journal of Plant Taxonomy
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• v.36 no.4
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• pp.263-277
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• 2006

Anemone pendulisepala, recently described as a new species, is distributed in sympatry with A. reflexa, A. amurensis, and A. raddeana at Mt. taebeark and Mt. Baekdu. Anemone pendulisepala was previously proposed to be a hybrid species between A. reflexa and A. amurensis becaue it displavs overlapping features with them in involucre shape, petiole length, sepal apex and xylem shape, To verify the taxonomic status and to examine the hybridity of A. pendulisepala, sequences of ITS region of nuclear ribosomal DNA and the psba-trnH, rps16 and trnLF region of cpDNA from 36 accessions of 5 taxa including outgroup were analyzed. In maximum parsimony tree based on ITS sequences, A. pendulisepala had the same sequences of A. reflexa and was clustered with monophyletic A. amurensis, and then A. raddeana. Anemone pendulisepala was distinguished from the other taxa by having four base insertion in rps16 region, two species-specific bases and insertion in trnLF region. In the phylogenetic trees of combined cpDNA, A. pendulisepala showed monophyly with the bootstrap 100%. Anemone pendulisepala exhibited no polymorphism and shared no sequences with putative parental or related taxa examined in this study. Molecular data suggest that A. pendulisepala should be a distinct species, and no evidence of the hybridization was detectcd.

• Korean Journal of Plant Taxonomy
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• v.45 no.2
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• pp.145-157
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• 2015

The nucleotide sequences of nuclear ribosomal ITS regions and chloroplast rbcL, matK and psbA-trnH regions of 30 individuals of Dendrobium moniliforme from several localities in four countries and 28 related species of Dendrobium were compared to investigate the genetic differences among Korean, Japanese, Taiwanese and Chinese D. moniliforme, and to verify the homogeneity of D. moniliforme, which is used as a traditional medicine in East Asia. A phylogenetic analysis showed that Korean D. moniliforme and Japanese D. moniliforme form a monophyletic group, with no significant differences between their nucleotide sequences. This confirms that they are the same species. However, the Chinese and Taiwanese D. moniliforme were polyphyletic. Various species related to D. moniliforme were located between the Korean-Japanese D. moniliforme and the Chinese-Taiwanese D. moniliforme, and other related species were found between individuals of Chinese-Taiwanese D. moniliforme. D. moniliforme is described in Japan, providing evidence that the Korean-Japanese D. moniliforme is the original species. In addition, our data suggest that the Chinese-Taiwanese D. moniliforme complex is a mixture of a range of other species. Further studies are required to understand the taxonomic identity of this species. In the Korean-Japanese D. moniliforme, there were almost no genetic differences among the localities, whereas the genetic heterogeneity was high among individuals of the Chinese-Taiwanese D. moniliforme.

• Korean Journal of Plant Resources
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• v.18 no.2
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• pp.260-269
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• 2005

Taxonomic studies on morphological, principal component analysis (PCA), palynological, RAPD and PCR-RELP analysis were conducted to intraspecific relationships of Rubus oldhami. Three types of Rubus oldhami based on the flower characters such as petal length and number were used in this study. Among the 14 morphological characters, perianth length, calyx lobe length, apical leaflet shape and leaflet length were used to distinguish for each type. The pollen characters such as shape, aperture number, surface sculpture were showed very similar among three types. Eight primers out of 20 arbitrary primers were screened for three types, and were revealed 33 ($60\%$) polymorphic bands. The phonogram by RAPD data showed incongruent with morphological analysis. Even though ten restriction endonucleases produced 20 restriction sites, polymorphic bands were not observed. Based on the results, three types of Rubus oldhami divided well by morphological characters, but pollen and DNA data were not supported. Therefore, type 1 and 2 which different from type 3 by flower characters considered as a temporary hybrid or ecotype because of their similar habitats.

• Korean Journal of Plant Resources
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• v.25 no.1
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• pp.142-151
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• 2012

This study was carried out to evaluate genetic variation of early-heading rice (Oryza sativa L. cv. Dongjin 1) lines derived from gamma-ray ($^{60}Co$, 300 Gy) irradiation. The average heading date of the 5 early-heading lines in $M_7$ and $M_8$ generation was faster than that of untreated control as 11 (line ${\gamma}$-2), 10 (line ${\gamma}$-5), 6 (${\gamma}$-1 line), 5 (${\gamma}$-3) and 4 days (line ${\gamma}$-4), respectively. According to ISSR analysis, polymorphic rate of the early-heading lines (from 5.9% to 23.4%) was higher than that of control (4.3%). The result indicates that the gamma-ray promote variation at DNA level. When genetic variations of rps16-trnK region were evaluated by nucleotide analysis, nucleotide length of the rps16-trnK region was 664 bp in all the early-heading lines and control. Out of 5 sites of nucleotide transposition detected in the region, however, 2 sites were appeared only in the early-heading lines.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.237-244
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• 1996

Propanil [N-(3,4-dichlorophenyl) propanamide] which was applied at 4,200g ai/hapostemergence 7 days after seeding or transplanting, completely reduced the growth of shoot and root of barnyardgrass at 100% under dry condition while plant height, root length and shoot fresh weight of barnyardgrass at 63, 40 and 78%, respectively under water condition. On the other hand, the herbicide did not affect the growth of shoot and root of rice grown under water condition and transplanting condition, but reduced the plant height, root length and shoot fresh weight of broadcast rice on soil at 24, 18 and 28%, respectively, under dry condition. Microscopically, the epidermal cells of treated-barnyardgrasses under both conditions were severely constricted, chloroplasts in the cells of vascular bunble sheath were partially lacked, and mesophyll cells were often ruptured, whereas those of treated-rice were not affected. Histological observations showed that propanil reduced the thickness of leaf blade of barnyardgrass under both conditions at 36-48% due to mainly reduction and constriction of mesophyll cell, while it did not affect or even increased the thickness of leaves of rice under all conditions compared to control. These results indicate that broadcast rice on soil were more injured than drilled rice in soil under dry condition, however, in the other tested conditions ricer were not affected.

• Applied Biological Chemistry
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• v.37 no.5
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• pp.361-369
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• 1994

To study the light-induced expression mechanism and protein transport into the chloroplast, a rice genomic clone (GrbcS) for the small subunit of ribulose 1,5-bisphosphate carboxylase (rbcS) was isolated and its nucleotide sequence was determined. Nucleotide sequence analysis of GrbcS revealed that the gene consists of two exons interrupted by an intron, encoding a protein of 175 amino acids including a transit peptide of 47 amino acids. These structural features of GrbcS are consistent with those of other rbcS genes from monocot species. Genomic Southern blot analysis suggested that the rbcS genes are present as a relatively small multigene family in the rice genome. Comparison of the nucleotide and deduced amino acid sequences to other rice rbcSs shows close sequence similaritiy. Conserved DNA sequences present in other light-responsive genes are also found in the 5’ upstream region of GrbcS such as G-box, 3AF1-binding site and GATA site. The possible function of these putative regulatory elements are discussed.