• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.51-55
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• 2000

To investigate the effect of media and growth regulators in micropropagation of persimmon (Diospyros kaki Thunb.), dormant axillary buds taken from trees of persimmon cultivars such as Ichikikeijiro, Tonawase and Hiratenenashi were used. Shoot tips were successfully cultured in full or half of nitrogen strength of MS medium. The most effective cytokinins for shoot proliferation and elongation of persimmon cv. Ichikikeijiro were 5 mg/L and 2 mg/L zeatin, respectively. Shoots were successfully rooted in 1/2N-MS medium with 1 mg/L IBA.

• Journal of applied mathematics & informatics
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• v.41 no.4
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• pp.839-848
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• 2023

Let G be a simple undirected graph. A planar graph known as a Halin graph(HG) is characterised by having three connected and pendent vertices of a tree that are connected by an outer cycle. A subset S of V is said to be a dominating set of the graph G if each vertex u that is part of V is dominated by at least one element v that is a part of S. The domination number of a graph is denoted by the γ(G), and it corresponds to the minimum size of a dominating set. A dominating set S is called a secure dominating set if for each v ∈ V＼S there exists u ∈ S such that v is adjacent to u and S₁ = (S＼{v}) ∪ {u} is a dominating set. The minimum cardinality of a secure dominating set of G is equal to the secure domination number γ_s(G). In this article we found the secure domination number of Halin graph(HG) with perfet k-ary tree and also we determined secure domination of rooted product of special trees.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.117-121
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• 2002

We have developed an in vitro micropropagation system via shoot formation from axillary buds using nodal segments of Corylopsis coreana. Explants from both juvenile tree (one-year-old greenhouse stock seedlings) and mature tree (ten-years-old tree in nursery) were compared with regard to propagation efficiency. Combined treatment of both BA and zeatin were effective on shoot proliferation since the best result was obtained on MS medium supplemented with 0.5∼3.0 mg/L zeatin and 0.2 mg/L BA. Generally, juvenile explants were better in both shoot proliferation and growth than mature explants. However, as the duration of in vitro culture was proceed to 6 months, explants from mature tree also produced three shoots per explant. Distinctive differences in rooting and adaptability to soil of shoots obtained from mother trees. Whereas shoots originated from juvenile explants rooted as high as 97%, those from adult explants showed 62% rooting. Similar result was also observed in soil acclimatization. The plantlets derived from juvenile plants survived 67%, while only 48% of those from adult trees survived. The results showed a possibility of the micropropagation of Corylopsis coreana through shoot formation from axillary buds. In addition, the advance of the research still remain to enhance the frequency of acclimatization of plantlets from mature trees for practical application.

• Plant Biotechnology Reports
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• v.3 no.3
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• pp.175-182
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• 2009

Simple, reproducible, high frequency, improved plant regeneration protocol in Eastern Cottonwood (Populus deltoides) clones, WIMCO199 and L34, has been reported. Initially, aseptic cultures established from axillary buds of nodal segments from mature plus trees on MS liquid medium supplemented with $0.25mg\;1^{-1}$ KIN and $0.25mg\;1^{-1}$ IAA. Nodal and internodal segments were found to be extra-prolific over shoot apices during course of aseptic culture establishment, while $0.25mg\;1^{-1}$ KIN concentration played a stimulatory role in high frequency plant regeneration. Diverse explants, such as various leaf segments, internodes, and roots from in vitro raised cultures, were employed. Direct plant regeneration was at high frequency of 92% in internodes, 88% in leaf segments, and 43% in root segments. This led to the formation of multiple shoot clusters on established culture media with rapid proliferation rates. Many-fold enhanced shoot elongation and growth of the clusters could be achieved on liquid MS medium supplemented with borosilicate glass beads, which offer physical support for proliferating shoots leading to faster growth in comparison to semi-solid agar or direct liquid medium. SEM examination of initial cultures confirmed direct plant regeneration events without intervening calli. In vitro regenerated plants induced roots on half-strength MS medium with $0.15mg\;1^{-1}$ IAA. Rooted 5- to 6-week-old in vitro regenerated plants were transferred into a transgenic greenhouse in pots containing 1:1 mixture of vermicompost and soil at $27{\pm}2^{\circ}C$ for hardening and acclimatization. 14- to 15-week-old well-established hardened plants were transplanted to the field and grown to maturity. The mature in vitro raised poplar trees exhibited a high survival rate of 85%; 4-year-old healthy trees attained an average height of 8 m and an average trunk diameter of 25 cm and have performed well under field conditions. The regeneration protocol presented here will be very useful for undertaking genetic manipulation, providing a value addition to Eastern Cottonwood propagation in future.

• Journal of Korean Society of Forest Science
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• v.90 no.6
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• pp.734-741
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• 2001

The two-month-old rooted-cuttings of Populus alba ${\times}$ glandulosa, P. euramericana and P. nigra ${\times}$ maximowiczii clones were exposed to livestock waste water - one of major water pollutants, and ground water in order to determine the effects of livestock waste water on growth response and absorption capacity of the species. For this purpose, 5 clones of each species were used. In all the species, the height growth of rooted-cuttings was better in livestock waste water treatment than in ground water. Of all the poplar species compared, the height growth was best in P. alba ${\times}$ glandulosa. In the cases of P. euramericana and P. nigra ${\times}$ maximowiczii, the height growth in the livestock waste water treatment was statistically different among clones, whereas there was no significant difference among P. alba ${\times}$ glandulosa clones. Aboveground biomass such as leaf and shoot dry weight of all the species increased in the livestock waste water treatment, while root dry weight decreased. In addition, chlorophyll contents in leaf of all the poplar species increased in the livestock waste water treatment. All the poplar trees showed temporal variation in the absorption amount of livestock waste water during the experimental period. In all the poplar species, the absorption amount of livestock waste water was less than that of ground water. Of 3 poplar species, P. alba ${\times}$ glandulosa was best in the absorption capacity of livestock waste water. Of all 15 poplar clones compared in this study, the 72-16 clone of P. alba ${\times}$ glandulosa showed the best absorption capacity.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.291-296
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• 2012

Triploids are a useful tool for biomass production and molecular breeding of trees with a long life span. Triploids of the poplar 'Hyunsasi' (Populus alba ${\times}$ P. glandulosa) have been developed by crossing between female diploids and a male tetraploid. The tetraploid was developed around the 1970s at Korea Forest Research Institute by colchicine-induced chromosome doubling. Seedlings of the $F_1$ generation were analyzed using flow cytometry to verify their ploidy status. The mean relative fluorescence index of 3 F1 poplars, labeled as Line- 1, Line-17, Line-18, were approximately 1.5 times higher than those of diploid poplars, and the results clearly indicated that they were triploids. The phenotype of the F1 poplars included larger leaves and thicker stem than diploids, and abnormal leaf morphology, especially in the triploid 'Line-18'. Three triploid lines developed roots more slowly and had less roots than diploid. However, 3 poplar cytotypes (2x, Line-1, Line-17) rooted within 10 days on MS medium. In contrast, compared with the 3 cytotypes, the Line-18 showed about 80% and 70% in the rooting rate and the number of roots. The triploid poplars could be directly utilized for biomass production and with their sterility, they could serve as basic material for genetic transformation. In addition, flow cytometric analysis proved to be an effective and reliable method for screening forest trees for their ploidy level.

• Journal of Korea Multimedia Society
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• v.7 no.10
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• pp.1436-1442
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• 2004

A shared-based tree established by the Core Based Tree multicast routing protocol (CBT), the Protocol Independent Multicast Sparse-Mode(PIM-SM), or the Core-Manager based Multicast Routing(CMMR) is rooted at a center node called core or Rendezvous Point(RP). The routes from the core (or RP) to the members of the multicast group are shortest paths. The costs of the trees constructed based on the core and the packet delays are dependent on the location of the core. The location of the core may affect the cost and performance of the shared-based tree. In this paper, we propose three methods for selecting the set of candidate cores. The three proposed methods, namely, k-minimum average cost, k-maximum degree, k-maximum weight are compared with a method which select the candidate cores randomly. Three performance measures, namely, tree cost, mean packet delay, and maximum packet delay are considered. Our simulation results show that the three proposed methods produce lower tree cost, significantly lower mean packet delay and maximum packet delay than the method which selects the candidate cores randomly.

• Tuberculosis and Respiratory Diseases
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• v.81 no.3
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• pp.216-221
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• 2018

Background: The number of immigrants with tuberculosis (TB) increases each year in South Korea. Determining the transmission dynamics based on whole genome sequencing (WGS) to cluster the strains has been challenging. Methods: WGS, annotation refinement, and orthology assignment for the GenBank accession number acquisition were performed on two clinical isolates from Chinese immigrants. In addition, the genomes of the two isolates were compared with the genomes of Mycobacterium tuberculosis isolates, from two native Korean and five native Chinese individuals using a phylogenetic topology tree based on the Multiple Alignment of Conserved Genomic Sequence with Rearrangements (Mauve) package. Results: The newly assigned accession numbers for two clinical isolates were CP020381.2 (a Korean-Chinese from Yanbian Province) and CP022014.1 (a Chinese from Shandong Province), respectively. Mauve alignment classified all nine TB isolates into a discriminative collinear set with matched regions. The phylogenetic analysis revealed a rooted phylogenetic tree grouping the nine strains into two lineages: strains from Chinese individuals and strains from Korean individuals. Conclusion: Phylogenetic trees based on the Mauve alignments were supposed to be useful in revealing the dynamics of TB transmission from immigrants in South Korea, which can provide valuable information for scaling up the TB screening policy for immigrants.

• Journal of Korean Society of Forest Science
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• v.94 no.4 s.161
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• pp.281-286
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• 2005

Trees enhance slope stability against down slope mass movement through the removal of soil water by transpiration and by the mechanical reinforcement of their roots. To assess the magnitude of this reinforcement on natural slope stability, direct shear tests were made on dry sand reinforced with different array types of roots. Pinus koraiensis was used as root specimens. The peak shear resistance at each normal stress level was measured on the rooted and unrooted soil specimens. Increased soil resistance(${\Delta}S$) by roots was calculated using parameters like internal friction angle and cohesion of tested soil and also evaluated the effects of root array in tested soil. As results, we find that shear resistance increased in tested soil shear box as diameters and arrayed numbers of root specimen increased and cross root array in tested soil had a much greater reinforcing effect than other root arrays. Comparison of traditional root-soil model with experiments showed that simulated reinforce strength by the model was different with those obtained by the experiment due to its linearity.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.107-113
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• 2002

This study was performed to obtain the information on fruit set, propagation and flowering habits of the exotic ornamental bottle brush tree (Callistemon citrinus). Trees have fruit capsules for four years since the fruit set and they have enlarged for three years. While 2 and 3-year-old capsules have similar seeds in number and size, 1-year-old ones have fewer and smaller seeds. Most dried capsules open when they have 75％ relative water contents. Two year old seeds which they were dried at 30％ germinated better than others. Removal of capsule bearing twigs resulted in greatly increased subsequent flower numbers (an average of 14 flowers per tree) compared with twigs where seed capsule were allowed to remain. In cutting for propagation, semi-hard wood branches dipped in 100mgι$^{-1}$ IBA for 24 hours rooted at 86.4 ％ and had an average of 12.6 primary roots.