• The KIPS Transactions:PartD
• /
• v.12D no.4 s.100
• /
• pp.543-552
• /
• 2005

As random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. The disk-based spatial indexing techniques, however, cannot direct apply to main memory databases, because the main purpose of disk-based techniques is to reduce the number of disk accesses. In main memory-based indexing techniques, the node access time is much faster than that in disk-based indexing techniques, because all index nodes reside in a main memory. Unlike disk-based index techniques, main memory-based spatial indexing techniques must reduce key comparing time as well as node access time. In this paper, we propose an efficient spatial index structure for main memory-based databases, called Tmr-tree. Tmr-tree integrates the characteristics of R-tree and T-tree. Therefore, Nodes of Tmr-tree consist of several entries for data objects, main memory pointers to left and right child, and three additional fields. First is a MBR of a self node, which tightly encloses all data MBRs (Minimum Bounding Rectangles) in a current node, and second and third are MBRs of left and right sub-tree, respectively. Because Tmr-tree needs not to visit all leaf nodes, in terms of search time, proposed Tmr-tree outperforms R-tree in our experiments. As node size is increased, search time is drastically decreased followed by a gradual increase. However, in terms of insertion time, the performance of Tmr-tree was slightly lower than R-tree.

• Journal of Plant Biotechnology
• /
• v.43 no.3
• /
• pp.272-280
• /
• 2016

Chrysanthemum is one of the top floriculture species with ornamental and medicinal value. Although chrysanthemum breeding program has contributed to the development of various cultivars so far, it needs to be advanced from the traditional phenotype-based selection to marker-assisted selection (molecular breeding) as shown in major cereal and vegetable crops. Molecular breeding relies on trait-linked molecular markers identified from genetic, molecular, and genomic studies. However, these studies in chrysanthemum are significantly hampered by the reproductive, genetic, and genomic properties of chrysanthemum such as self-incompatibility, inbreeding depression, allohexaploid, heterozygosity, and gigantic genome size. Nevertheless, several genetic studies have constructed genetic linkage maps and identified molecular markers linked to important traits of flower, leaf, and plant architecture. With progress in sequencing technology, chrysanthemum transcriptome has been sequenced to construct reference gene set and identify genes responsible for developments or induced by biotic or abiotic stresses. Recently, a genome sequencing project has been launched on a diploid wild Chrysanthemum species. The massive sequencing information would serve as fundamental resources for molecular breeding of chrysanthemum. In this review, we summarized the current status of molecular genetics and genomics in chrysanthemum and briefly discussed future prospects.

• Korean Journal Plant Pathology
• /
• v.1 no.3
• /
• pp.199-206
• /
• 1985

Viroids are the smallest. well-characterized infectious agents presently known. and so far viroids have been found only in higher plants. The structures of viroid-molecules are single-stranded, covalently closed circular RNA molecules with a range of 240 to 380 nucleotides according to the various viroids. Viroids are remarkable not only as a new category of pathogen, which cause economically important diseases, but also as an excellent model system for biochemical and biophysical investigations because of their small size, relative stability and their self-replication. Four different patato spindle tuber viroid isolates, which express the different symptoms on the same host plant exchange only 2 to 6 nucleotides in the total number of 359 nucleotides, but now the mechanism of viroid pathogenicity is not explained fully. Viroid-melecules are replicated without any special viroid-associated proteins, and during the process of viroid replication oligomeric viroid-associated RNAs are detected at nuclei of viroid infected leaf tissue. The mechanism of viroid replication can now be illustrated according to a possible explanation of rolling-circle system. Although the rapid progress have been made in elucidation of the biochemical and biophysical properties of PSTV and other viroids, the mechanism of viroid replication and pathogenicity is less known and is still a matter of speculation. When these problems can be sufficiently explained, the viroid molecule could play an important role as an available vector in plant genetic engineering.

• Korean Journal of Medicinal Crop Science
• /
• v.12 no.1
• /
• pp.17-23
• /
• 2004

This study was carried out to obtain the basic information on mating parents and selection for high yielding safflower breeding. Thirty nine world safflower lines, which had collected from 13 countries of origjn, were evaluated for major agronomic characters, correlation and path-coefficients. The results obtained were summarized as follows. Days to flowers ranged from 83 days to 100 days. Days to flower of most foreign lines were later than that of domestic lines. Plant height ranged from 75 cm to 162 cm. The plant height and stem diameter of most foreign lines were higher than those of domestic lines. The leaf number and size of domestic lines were much more than those of foreign lines. The total branch numbers of foreign lines were more than domestic lines. Particularly, the number of third branch ranged from 0 to 25 and there were none in domestic lines. The number of corolla of foreign lines was much more than that of domestic lines. The yield of foreign lines collected from Central Asia and United States of America were more than any others. Significantly positive correlations were observed between yield and days to flower, stem diameter, the number of branch and the number of corolla. In the analysis of path-coefficient, the highest direct effects on yield was the number of corolla followed by the number of total branch, whereas those of the number of second branch and stem diameter were negative.

• The Korean Journal of Mycology
• /
• v.16 no.3
• /
• pp.151-156
• /
• 1988

A leaf anthracnose disease of pepper(Capsicum annuum L.) seedling caused by Colletotrichum coccodes was found in fields of Chungnam District for the first time in 1988. Initial symptom of the disease was spotting on leaves and stems of the seedlings. The spots became sunken and gradually increased in size and coalesced to form bigger irregular spots and blights on the leaves. In severely affected fields, many pepper seedlings were defoliated and lodged. Field survey revealed that the infection rate of anthracnose ranged form 15.3% to 92.3%. Conidia from lesions on seedlings were hyaline, aseptate, straight, cylindrical with obtuse ends, $115-25(av.\;19.\;5){\times}2.5-4.8{\mu}m(av.\;3.3{\mu}m)$ and setaes were straightly extended above the acervuli, $41.3-136.3\;{\um}m(av.\;85.0{\mu}m)$ long. The fungus produced abundant sclerotia on PDA when it was cultured under darkness. In the inoculation experiments, the fungus was found to infect pepper seedlings and fruits, and fruits of tomato and egg plant.

• Korean Journal of Environmental Biology
• /
• v.27 no.2
• /
• pp.198-204
• /
• 2009

From leaf mold and reclamation site soil of the Capital area of Korea, 3 poly(butylene succinate-co-butylene adipate: PBSA)-degrading strains were isolated through the clear zone test. The PBSA-degrading activities of the strains were assessed by means of a modified Sturm test using 0.01% of PBSA film as a sole carbon source. After the modified Sturm tests for 40 days at the respective isolation temperatures, the 3 strains degraded 30%, 55% and 43% of PBSA, respectively. The isolated strains were identified to be Burkholderia cepacia PBSA-4, Bacillus licheniformisPBSA-5 and Burkholderia sp. PBSA-6 through the 16S rDNA gene sequence analysis. Among them, PBSA-5 degraded both PBSA and Poly(vinyl alcohol). The degradation activity of the PBSA degrading strains appeared to be high at moderate temperatures such as $27^{\circ}C$ and $37^{\circ}C$, and initial inoculum size of $10^{10}cfu\;mL^{-1}$ degraded PBSA 1.2~1.3 more times than that $10^9cfu\;mL^{-1}$. Addition of 0.1 or 0.5% (w/w) of gelatin, yeast extract and ammonium sulfate raised the PBSA degrading activity, and especially addition of 0.1% (w/w) of gelatin enhanced the PBSA degrading activity by more than 33%. The mixed strains degraded PBSA faster than the single strain.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.10 no.2
• /
• pp.84-96
• /
• 2007

The purpose of this study was to select herbaceous plants that can be used for presenting various views and biodiversity on the extensive rooftop greening. Experiment plots were constructed in July 2005 on the rooftop of the Administration Building in the Seoul Women's University. For this experiment, planters were used to design rooftop greening. The size of a planter is 500mm${\times}$500mm${\times}$100mm and each planter has the water storage plate in the lower part of it. The soil was constructed by mixing pearlite, vermiculite, cocopeat, and leaf mold in the ratio of 6 : 2 : 1 : 1. The plot was divided into the watered plot and the dry plot. Since each plot was constructed 2 times, finally 4 planters were constructed in total. One hundred species were used for the experiment and 9 plants per species were planted in each planter. Plants were organized according to types of plants and the experiment used 86 native herbaceous plants, 6 herbs, and 8 foreign plants. The plots were monitored once a month, from July to November 2005. The length and width of plants were tape-measured and covering rate was calculated by CAD program. "SPSS 10.1" was used for a statistical analysis. The result showed no significant difference between the watered plots and the dry plots. In cases of some plants, there were statistically significant differences between the watered planter and dry planter such as follows : Astilbe chinensis and Polygonatum odoratum which are shade plants were measured as the highest value on the watered pots, and Aquilegia buergeriana, Chrysanthemum zawadskii, Calendula arvensis and Gypsophila cerastioides D.Don which are sunny plants were measured as the highest value on the dry plots. According to the final analysis of the data collected and observed for growth condition during the first year of the research, 51 species including Prunella vulgaris var. lilacina and Veronica linaiaefolia in native herbaceous plant, 5 species with Lavandula angustifolia in herbs, and 3 species with Lantana camara and Muscari armeniacum in foreign plants showed the highest growth condition. In conclusion, it is suggested that various plants including sedums could be effectively used for extensive rooftop greening to improve landscape(a view) of the rooftop and increase ecological values.

• Proceedings of the Ginseng society Conference
• /
• 1974.09a
• /
• pp.9-22
• /
• 1974

Unlike the tissue culture in animals and human being, in higher plants various parts of the plant are cultured for varied purposes, and they are named variously depending on which parts are used as explants or what purposes they are cultured for. Followings are some of the names of culture used frequently: organ culture, tissue culture, callus culture, single cell culture, meristem culture, mericlone culture, ovary culture, ovule culture, embryo culture, endosperm culture, anther culture, pollen culture, protoplast culture, etc.. As the names of the culture indicate, in some kinds of culture the explants used for culture are actually not tissues, but organs, single cells, or protoplasts. It seems, however, convenient to call all of the above-mentioned cultures grossly as tissue culture. Several kinds of tissue culture were attempted using Panax ginseng as material and some of the results were summarized below. 1. Callus culture After dormancy of the sed was broken, whole embryo or parts (hypocotyl, cotyledon and epicotyl) of partly grown embryo were cultured in the media supplemented with growth regulators. Rapid swelling occurred in a few weeks, but most of the swelling was observed only in the basal part of epicotyl, changes in the other parts of embryo appearing in much later stages. The swelling or increase in size, however, was resulted not from the divisions of cells, but from the mere expansion of cell. Real calli were formed about two months after inoculation of explants. Callus tissues developed from cortex, pith, and vascular bundle in the cases of hypo- and epicotyl, from mesophyl tissue in the case of cotyledon. Shoots developed more easily from cotyledons regardless of whether they are detached from or attached to the embryo proper. 2. Culture in the Knudson C medium When cotyledons, detached from or attached to the embryo proper, were cultured in the growth regulator-free Knudson C medium comprision only several kinds of mineral compounds and sucrose, shoot primordium or callus developed profusely and finally plantlets were produced directly from shoot primordium or indirectly through callus. In this medium epidermal cells as well as mesophyl cells of the cotyledon became meristematic and divided, changing into multinucleate cells or multicellular bodies, developing eventually into either shoot primordia or calli. 3. Anther culture Anthers were cultured in the media supplemented with various growth regulators applied singly or in combinations. Callus was formed mostly in the connective tissue of anther. Cells of anther wall layers changed in appearance, but no division occurred. Microspores of all stages in development were not changed, ruling out the possibility that microspore-originated callus might be formed. 4. Isolation of protoplast Protoplasts were isolated from young root, leaf, and epicotyl, using 0.7M D-mannitols as osmoticum and using macerozyme and cellulase respectively for maceration and digestion of the cell wall. Production in large number of naked intact protoplast was rather difficult as compared with other plant species. Fusion of protoplasts occurred infrequently mainly due to the fewer number of naked protoplasts in the solution.

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

• Journal of the Korea Organic Resources Recycling Association
• /
• v.10 no.2
• /
• pp.71-81
• /
• 2002

The study was carried out to develop nursery soil for rice seedling of phyllite. First of all, physico-chemical properties of used phyllite in the study through the analysis for agricultural utilization evaluation are as following. Bulk density(BD) of phyllite was $1.31g/cm^3$ each other and porosity had 65% of entire pore size. Also, the water holding capacity(WHC) was 43% at 1/3bar pressure, which phyllite has high WHC. According to, the results the experiments for nursery soil were conducted by mixing the materials such as phyllite, zeolite and hill soil. The mixing ratios were 30, 50, and 70% for zeolite and hill soil into phyllite. These mixed materials were packed in a box by adding 0, 1 and 2g of N-fertilizer. At seedling test, there were increases in the growth of shoot and root of rice for phyllite to zeolite and phyllite to hill soil, respectively. On the other hand, the length of leaf increased with increasing application rate of phyllite, while length and a number of root increased with increasing application rate of hill soil. The growth in the plots of phyllite to zeolite and phyllite to hill soil was better than in control plot. Finally, phyllite plot had efficient results when it compared with others and the study used with phyllite will have to more research and effort for agricultural useful material.