• Journal of Crop Science and Biotechnology
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• v.11 no.2
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• pp.111-118
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• 2008

Soybean is sensitive to waterlogging stress, leading to reduce their growth and yield significantly. The objective of this study was to characterize the relative sensitivities of biomass accumulation and specific nodule activity under waterlogging stress between supernoduating mutants, 'SS2-2' and 'Sakukei 4' and their wild-type soybeans, 'Sinpaldalkong 2' and 'Enrei', respectively. Flooding treatment was performed to soybean plants grown in a pot by waterlogging for 15 days from the beginning bloom(R1) stage under natural light. The nodule number and weight were considerably decreased by waterlogging stress. The bleeding sap rate of waterlogging soybean plants was decreased by 78-80% in supernodulating mutants and 65-74% in their wild types compared to control plants. The relative ureide-N content was also decreased by waterlogging and the reduction was high in supernodulating mutants. This may cause the massive reduction of shoot and root dry weight and leaf area in waterlogged soybean plants. There was a varietal difference in response to the waterlogging stress. During the waterlogging, supernodulating mutants maintained higher spad value than their wild types. Particularly, the difference between soybean varieties was clear in low rank leaves from the top. Also, supernodulating mutants showed a weak waterlogging tolerance than their wild types. Under waterlogging conditions, massive nodules were considerably destroyed and specific nodule activity after waterlogging may not be recovered when compared to their wild-type soybeans. Supernodulating mutants showed lower seed yield than their wild types in waterlogging conditions.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.3 s.39
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• pp.137-141
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• 1990

This study was carried out to investigate the propagation methods of the Rhododendron micranthum as a landscape plant The results obtained are as follows :　1. The optimum temperature for seed germination was $20^{\circ}C$, and the seed germination needs light. 2. GA and thiourea did not affect the seed germination under light, but GA gad substitutive effect. 3. 87% and over of germination rates were obtained in room temperature and $5^{\circ}C$ dry storages. 4. The rooting rate was high on sandy loam, vermiculite, and vermiculite 50%+sand 50%, at softwood and hardwood cutting(hardwood ; 45~48%, softwood ; 45~48%). 5. The significant effects on rooting were found with the treatment of NAA 500~2000ppm.

• Korean Journal of Plant Tissue Culture
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• v.24 no.4
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• pp.239-256
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• 1997

Plants belonging to the category of 2n apomixis or agamospermy form embryos and seeds without the processes of normal meiosis and syngamy. Seeds produced in this way have identical genotype of their maternal parent. Three different types of agamospermy are recognized: diplospory, apospory, and adventitious (adventive) embryony. $F_1$ hybrid cultivars cannot be used as seed sources in the next ($F_2$) generation because this generation would be extremely variable as a result of genetic segregation. Hybrid vigor is also reduced in the $F_2$ generation. Therefore, parental stocks for hybrid seed production need to be maintained and cross must be continuously repeated. Agamospermic 2n apomixis would make it possible to fix the genotype of a superior variety so that clonal seeds faithfully representing that genotype could be continuously and cheaply produced independent of pollination. That is, $F_1$ hybrid seeds could be produced for many generations without loss of vigor or genotype alteration. Production of apomictic $F_1$ hybrid seed would be simplified because line isolation would not be necessary to produce seed or to maintain parental lines, and the use of male-sterile lines could be avoided. Overall, apomixis would enable a significant reduction in hybrid seed production costs. Additionally, the production of clonal seed is not only important for seed propagated crops, but also for the propagation of heterozygous fruit trees and timbers. Clonal seed would help avoid costly and time-consuming vegetative propagating methods that are currently used to ensure the large-scale production of these plants. Apomixis is scattered throughout the plant kingdom, but few important agricultural crops possess this trait Therefore, most research to date has centered on introgressing the trait of apomixis into agricultural crops such as wheat, maize, and some forage grasses from wild distant relatives by traditional cross breeding. The classical breeding approach, however is slow and often impeded by many breeding barriers. These problems could be surmounted by taking mutagenesis or molecular approach. Arabidopsis thaliana is a tiny sexually reproducing plant and is convenient in constructing and screening in molecular researches. Male-sterile mutants of Arabidopsis are particularly suitable genetic background for mutagenesis and screening for apomictic mutants. Molecular approaches towards isolating the genes controlling the apomictic process are feasible. Direct isolation of genes conferring apomixis development would greatly facilitate the transfer of this trait to wide variety of crops. Such studies are now in progress.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.641-645
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• 2007

We conducted a seed germination screening under saline conditions to identify salt tolerance(sto) mutants with ethyl methane sulfonate(EMS) mutagenesis seed pool. During the screening, we identified three mutant lines that seemed to confer elevated salt tolerance in high concentrations of NaCl. At 175 mM NaCl, germination rate of sto42-14 mutant(one of the EMS salt tolerance mutants) was 7-fold higher than that of wild-type plants. Interestingly, sto42-14 mutant exhibited insensitivity to high glucose concentration and growth inhibition to gibberellin. Our results suggest that sto42-14 is involved in salt stress tolerance as well as in glucose and gibberellin response in Arabidopsis.

• Korean Journal of Plant Resources
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• v.19 no.6
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• pp.700-705
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• 2006

Present studies were performed to determine the physiology of seed germination in Viola species native to Korea. Twelve species, 1 variety and 1 form were collected, classified and used as materials: V. collina, V. blandaefomis, V. rosii, V. chaerophylloides, V. phalacrocarpa, V. patrinii, V. mandshurica, V. mandshurica for. albescence, V. seoulensis, V. yedoensis, V. keiskei, V. variegata, V. variegata var. chinensis, and V. verecunda. V. tricolor 'Helen Mount' was also used to compare wild with cultivated species. In order to investigate the effect of temperature on seed germination, seeds stored at $4{\pm}2^{\circ}C$ for 10 months or 4 years were incubated at 10, 15, 20, $25^{\circ}C$ under 16h illumination with 4 replicates per treatment. Seeds which had not germinated at $10^{\circ}C$ were transferred to $30^{\circ}C$ to assess the effect of temperature change in germination. Germination percent and the days of first, 40% and 80% germination were assessed. Capability of seed germination varied with taxon; Species belonging to subsection Patellares had high ability of germination, compared to species in the other subsections, and series Chinensis was the best among subsection Patellares. Species capable of high germination germinated in all temperatures with reasonably high germination rate, but the other species responded sensitively to temperature with different germination patterns. Higher the temperature, shorter the incubation time required for first, 40% and 80% of germination. Therefore, high temperature was effective in almost all species, not only for inducing high rate of germination but also the uniformity of germination. Temperature change from $10^{\circ}C\;to\;30^{\circ}C$ had a positive effect on seed germination.

• The Korean Journal of Ecology
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• v.13 no.3
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• pp.225-236
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• 1990

We studied that seeds of wild radish with different size of weight can be obtained for the purpose of differentiation and growth of these seeds by total growth periods. This study is practised a view of plant eco-physiological side and dry-matter production. Through whole growth periods, we knowthat seed weight of L plots was higher than that of M and S plots. In the 33th day after day after germination, growth values of L, M and S plots were 13.93, 7.77, and 4.61 g/plant, respectively. Growth of shoot (cotyledon and leaf) area and shoot weight were shown the similar trends with individual plant dry-amtter weight. In the 33th day after germination, shoot area of L, M and S plots were 21.55, 11.81 and 8.75 $cm^3$/plant and shoot dry weight of L, M and S plots were 10.83, 6.03, 3.50 g/plant, respectively. In the early stage of growth (the 10-14th day after germination), the values of RGR of seed weight of L, M, S plots were 0.2887, 0.2807 and 0.2365 g/g/day, in the late stage of growth, those values of RGR of L, M, S plote were 0.2721, 0.1716, 0.1727 g/g/day, respectively. In the early stage of growth (the 14th day after germination), the values of NAR or L, M and S plots were 0.1513, 0.1373, and 0.1094 g/$cm^2$/day, respectively. It is thought that seed weights were influenced seriously effect in the early stage of growth. The NAR value, in the late stage of growth (the-28-33th day after germination), of L, M and S plots were not large different as 0.1086, 0.1097 and 0.112 g/$cm^2$/day, respectively. The LAR values of M and S (2.0396, 2.1520 $m^2$/g) plots, in the early stage of growth, were higher than L (1.9037 $m^2$/g) plots. In the late stage of growth, the value of LAR of L plots were nearly same as M plots, but the value of S plots were higher than that of L and M plots (0.0458 $m^2$/g). And, in the early stage of growth, the values of SLA of L, M and S plots were 2.2123, 2.2107 and 2.8448 $m^2$/g, respectively. We measured the photosynthetic rates and the respiratory rates as the physiological characteristics of wild radish. In the early stage of growth, the photosynthetic rates of L, M and S plots were 12.4, 14.4, 9.8 $\mu$mol /$m^2$/sec and 9.4, 11.4, 9.8 $\mu$mol/$m^2$ /sec in the late stage of growth, respectively. In this result, it could be informed that photosynthetic rates in the late stage of growth were lower than the early stage. In the middle stage of growth, the respiratory rates were 0.793, $\mu$mol/$m^2$/min in shoot, and 3.28 $\mu$mol/$m^2$/min in root without relation to seed weight. The growth analysis of plants was used by Hunt & Parson s computer program (1974, 1981) and its results used this program were good. Therefore, in this sense, it could be expected that the computer program used and developed largely in researches of plant growth.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.42-42
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• 2021

산채류 종자는 주로 농가의 자가 채종으로 생산되고 있다. 농가에서는 종자만을 생산하기 위해서 산채를 재배하지 않으며, 대체로 산채를 수확한 후 채종하는 실정이다. 하지만 종자생산을 위해서 생채나 나물을 언제까지 수확해야 하는지에 대한 한계기 설정이 불분명하다. 따라서 전북농업기술원 허브산채시험장에서는 개미취와 섬쑥부쟁이는 5년생, 곤달비는 3년생 묘목을 이용하여 종자생산을 위한 적정 생채수확 한계기를 설정하고자 시험을 실시하였다. 55% 차광막을 설치한 노지 재배포장에서 생채 수확 한계기를 각각 2020년 4월, 5월, 6월까지로 두어 한계기별 생채 수량, 상품 수량 및 상품율과 개화 시기, 개화율 및 결실률 등을 조사하였다. 개미취의 생채 상품율은 수확 한계기가 늦어질수록 다소 떨어지는 경향이었으며, 개화 시기는 무처리와 4월까지 수확은 동일하였으나, 5월, 6월까지는 수확 한계기가 늦어질수록 지연되었다. 개화율은 대부분 10% 미만이었으며, 5월과 6월까지 생채를 수확한 경우는 추대 및 개화가 거의 되지 않았다. 섬쑥부쟁이는 생채를 6월까지 수확하면 4월까지 수확한 경우보다 약 2배 이상의 생채를 얻을 수 있으나 상품율은 확연히 떨어졌다. 개화 시작은 무처리와 4월까지 수확이 타 처리에 비해 빨랐으나 개화종은 시기에 상관없이 비슷하였다. 또 4월까지 생채를 수확한 경우 무처리보다 개화율, 결실률이 더 높았다. 5월 이후 수확은 생육 부진으로 이어져 개화 및 결실률이 매우 떨어졌다. 곤달비는 개미취와 섬쑥부쟁이에 비해 생채 수확 한계기가 늦어질수록 상품 수량이 눈에 띄게 증가하였으며, 처리 간 추대 시기도 차이는 없었다. 개화율은 5월 수확 이후 낮아졌으며, 결실률은 6월 이후에 급격히 떨어졌다. 따라서 채종을 위해서는 차광재배 시 개미취와 섬쑥부쟁이는 생채 수확시기를 4월 하순, 곤달비는 5월 하순까지로 한정해야 할 것으로 판단된다.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.1-8
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• 2002

This study was conducted to obtain the information of varietal development using wild soybean through investigation of variation and heredity of major agronomic characters in $F_2$ generation of interspecific cross between Glycine max and G. soja. In segregating populations of two crosses, all characters observed except 100-seed weight showed transgressive segregation. Days to flowering showed normal distribution; mean days to flowering in $F_1$, and $F_2$ was approximately mean of parent. Mean of $F_1$ for 100-seed weight was 6.2g and 5.7g for Eunhakong/KLG10084 and Sohaegnamulkong/KLG10084, respectively, which were somewhat skewed distribution to small seeded parents. Mean seed yield of $F_2$ was about mean of two parents. Degree of vine was 6.4 and 5.7 in $F_1$ for two crosses but it was 6.0 in $F_2$ for Eonbakong/KLG10084, which revealed the degree of vine as partial dominance while 4.6 for Sobaegnamulkong/KLG10084, somewhat different results from the previous cross. Broad-sense heritability($h^2B$) for plant height, days to flowering, pods per plant, seed yield, and degree of vine was comparatively high and narrow-sense heritability($h^2B$) for 100-seed weight which is the moot important character in the development of small seed-size sprout soybean was 52.3% and 65.6% for Eunhakong/KLG10084 and Sohaegnamulkong/KLG10084, respectively, which indicated that selection for the character in early generation was possible.

• Journal of the Korean Institute of Landscape Architecture
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• v.15 no.2
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• pp.139-148
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• 1987

Exochorda serratifolia, broad-leaved shrub has beautiful flowers and is resistant to cold, shade and decease. New this native plant is considered to be worth being exploited as the outstanding plant for landscaping and horticulture. So this study was executed to utilize Exochorda serratifolia as the planting material for landscaping and horticulture through the survey of its habitat environment and the experimennt of its seed physiology and germination, vegetative propagation, culture and utilization, etc.. The results are as follows ; 1. The color of the flower is white, blooming in the early and middle of May and the seeds ripen late in Sep.. 2. The elevation, elevation, gradient and direction of the native habitat were 250m, 20-25$^{\circ}$and northern side respectively. 3. The soil pH of the natural habitat was 5.3 and soil fertility was poor. 4. Exochorda serratifolia appeared as indicator within P. densiflora community and its neighboring species were Q. mongolica, Q. dentata, R. mucronulatum, L. obtusiloba, E. oxyphillus, C. heterolphylla, var thunbergii, etc.. 5. The optimum temperature for seed germination was found at 20$^{\circ}C$ and the longer the stratification period at 5$^{\circ}C$ was, the lower the germination rate was. 6. The treat merits of GA and Kinetin increased the seed germination rate, especially under the dark condition but their high concentrations decreased the seed germination rate. 7. The rooted rate of the greenwood cutting was the highest at IBA 100ppm plot of vermiculite bed but its high concentration decreased the rooted rate conspicuously. 8. In the tissue culture, the each 1.0 ppd plot of NAA, Kinetin and NAA 1.0ppm + Kinetin showed the best growth. And the mixture of NAA 1.0ppm and Kinetin showed better growth than the single treatment of NAA or Kinetin did. 9. Transplanted Exochorda serratifolia showed healthy growth with shaded environmental condition(42.1% light intensity), therefore they can be cultivated as a shade tolerant landscape plant. 10. It was considered that Exochorda serratifolia was applicable to group planting at shade places or under trees in parks, homes, etc..

• The Plant Pathology Journal
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• v.37 no.6
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• pp.555-565
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• 2021

Bacteriophages infecting Acidovorax citrulli, the causal agent of bacterial fruit blotch, have been proven to be effective for the prevention and control of this disease. However, the occurrence of bacteriophage-resistant bacteria is one of hurdles in phage biocontrol and the understanding of phage resistance in this bacterium is an essential step. In this study, we aim to investigate possible phage resistance of A. citrulli and relationship between phage resistance and pathogenicity, and to isolate and characterize the genes involved in these phenomena. A phage-resistant and less-virulent mutant named as AC-17-G1 was isolated among 3,264 A. citrulli Tn5 mutants through serial spot assays and plaque assays followed by pathogenicity test using seed coating method. The mutant has the integrated Tn5 in the middle of a cupin protein gene. This mutant recovered its pathogenicity and phage sensitivity by complementation with corresponding wild-type gene. Site-directed mutation of this gene from wild-type by CRISPR/Cas9 system resulted in the loss of pathogenicity and acquisition of phage resistance. The growth of AC-17-G1 in King's B medium was much less than the wild-type, but the growth turned into normal in the medium supplemented with D-mannose 6-phosphate or D-fructose 6-phosphate indicating the cupin protein functions as a phosphomannos isomerase. Sodium dodecyl sulfa analysis of lipopolysaccharide (LPS) extracted from the mutant was smaller than that from wild-type. All these data suggest that the cupin protein is a phosphomannos isomerase involved in LPS synthesis, and LPS is an important determinant of pathogenicity and phage susceptibility of A. citrulli.