• Korean Journal of Weed Science
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• v.9 no.3
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• pp.183-200
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• 1989

An experiment was conducted at the greenhouse of the International Rice Research Institute in 1987 to find out the character of dry matter production, the potential seed production ability and the ecological and physiological strategies to adaptation. For these, two rice cultivars, IR64(lowland rice) and UPLRi-5(upland rice), and seven weed species were used ; Echinochloa glabrescens Munro ex Hook. f., E. cress-galls ssp. hispidula (Retz.) Honda, E. colons (L.) Link, Monochoria vaginalis (Burin. f.), Ludwigia octovalvis Jacq.) Raven, Fimbristylis miliacea Vahl and Cyperus difformis L. Adaptation strategies of weed species varied by species. However, they had efficient seed production strategy through different ways. In general, sedge weed species (F. miliacea and C. difformis) produced great amount of seeds at the expense of seed size through greater ratooning ability and low relative dry weight for flowering. For broadleaved weed species, greater number of descendants were obtained through high plasticity and low relative dry weight for flowering (M. vaginalis) or greater growth ability through effective photosynthetic efficiency (L. octovalvis). Grass weed species, on the other hand, produced their seeds through effective growth (net assimilation rate and relative growth rate), high ratooning ability (except E. crus-galls ssp. hispidula) or low relative dry weight to maximum dry weight for flowering (E. glabrescens). The harvest indices of the weed species were considerably lower than those of rice. Fimbristylis miliacea had the greatest ratooning ability followed by C. difformis, E. colons and E. glabrescens. The greatest seed productivity was recorded by C. difformis (279, 000) and L. octovalvis (268,000) while rice produced the least number of seeds (1300-6100). Log seed weight had a negative linear relationship with log seed number (y=6.30-1.48X, $R=-0.965^{**}$). For all species plant plasticity response was not directly correlated with mortality response.

• FLOWER RESEARCH JOURNAL
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• v.19 no.1
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• pp.15-21
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• 2011

This study investigated the effect of soil mulching materials and methods on weed occurring for the growth and flowering characteristics in Gypsophila plants cultivation. For mulching materials were used black polyethylene (PE) film, black polypropylene (PP), and green polypropylene, and these were mulched in both ridge and furrow (BRF) or only furrow, respectively. The weed was occurred total $146.2g/m^2/yr$ as dry weight in non-mulching, but $4.1{\sim}4.2g/m^2/yr$ in BRF mulching by black or green PP. Also weed control were yearly required 27.9 persons/10a in non-mulching, whereas 2.4 persons/10a in BRF mulching by black or green PP. Flower budding and blooming were roughly delayed in non-mulching and furrow mulching. Flowering characteristics such as flower stalk length, primary branches number, and stem firmness were remarkably improved in BRF mulching of black or green PP. Cut flower yield was increased on black BRF mulching or green PP in summer cultivation, while green PP BRF mulching showed better yield in in autumn cultivation. Mortality rate of Gypsophila plants after summer season was lowest as 12.4% in furrow mulching with black PP, followed by about 19.0% in green PP mulching, but highest as 39.0% in BRF mulching with black PE film. Rosette formation rate was lower in furrow than BRF mulching, and was lowest as 13.1% in BRF mulching with green PP, followed by 15.2~15.8% in BRF mulching with black PE film or black PP. So it was thought that BRF mulching with green PP was highly effective in weed control and improvement of yield and cut flower quality in Gypsophila plants cultivation.

• Korean Journal of Agricultural Science
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• v.15 no.1
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• pp.36-46
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• 1988

Twelve soybean cultivars were cultivated in the 1/2,000a. Wagner pots with irrigation and without irrigation for 30 days after flowering, and the differences of plant growth and bean yield among cultivars were compared. And to investigate the varietal differences in the rate of photosynthesis under different relative humidity, 6soybean cultivars were cultivated in 1/2,000a. Wagner pot and the rate of photosynthesis of each soybean cultivar at flowering time was measured under the relative humidity of 80, 70, 60, 50 and 40%. The results obtained are summarized as follows; 1. The days to maturity of the soybean cultivars were shortened by non-irrigation treatment. The response of the maturing dates to non-irrigation was significantly different among the soybean cultivars. The days for maturing of Paldal, Danyeob and Eundaedu were delayed 2 days but those of Jangbaek and Tamahomare were delayed about 7 to 8 days under non-irrigation treatment. 2. The stem length, stem diameter, number of nodes of the mainstem, number of branches and number of branch nodes of all soybean cultivars were decreased by non-irrigation treatment. The number of branches and the number of branch nodes were especially severely influenced by non-irrigation treatment. 3. The number of pods per plant and the number of perfect pods was significantly reduced by non-irrigation treatment but the number of imperfect pods was increased. The non-irrigation treatment reduced the number of pods per plant by 58.0% and the ratio of the number of the perfect pods per plant by 46.6% relative to the ordinary cultivation with irrigation. 4. The grain yield of all cultivars was significantly reduced by the non-irrigation treatment, and average grain yield of soybean cultivars cultivated under non-irrigation treatment was 35.9% of that of soybean cultivars cultivated with irrigation. The influence of non-irrigation treatment was lowest in Paldal and significantly high in Tamahomare and Jangbaek. 5. The rate of photosynthesis of soybean leaves was significantly different among cultivars and was also influenced by relative humidity. Ratio of the photosynthetic amount of soybean leaves at 40% RH to the maximum photosynthesis at optimal humidity was 97.2% in Paldal, 96.4% in Danyeob and 88.8% in Baekun. 6. At 40% relative air humidity, highly significant correlations were found among the photosynthesis rate, the amount of transpiration and the respiration rate.

• Korean Journal of Plant Taxonomy
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• v.47 no.2
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• pp.124-131
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• 2017

Species identification is a fundamental and routine process in plant systematics, and linguistic-based dichotomous keys are widely used in the identification process. Recently, novel tools for species identification have been developed to improve the accuracy, ease to use, and accessibility related to these tasks for a broad range of users given the advances in information and communications technology. A visual identification key is such an approach, in which couplets consist of images of plants or a part of a plant instead of botanical terminology. We developed a visual identification key for 101 taxa of Orchidaceae in Korea and evaluated its performance. It uses short statements for image couplets to avoid misinterpretations by users. The key at the initial steps (couplets) uses relatively easy characters that can be determined with the naked eye. The final steps of the visual key provide images of species and information about distributions and flowering times to determine the species that best fit the available information. The number of steps required to identify a species varies, ranging from three to ten with an average of 4.5. A performance test with senior college students showed that species were accurately identified using the visual key at a rate significantly higher than when using a linguistic-based dichotomous key and a color manual. The findings presented here suggest that the proposed visual identification key is a useful tool for the teaching of biodiversity at schools, for the monitoring of ecosystems by citizens, and in other areas that require rapid, easy, and accurate identifications of species.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.126-131
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• 1996

In this study effects of isolation distance, transplanting time of maternal plants, and bagging of flower head with the gauze-cloth bag on the outcrossing of burley tobacco (Nicotiana tabacum L.) were investigated. Also the effect of fertilizer level and control of the number of capsules per plant on seed production and quality were examined. A male sterile line. produced 0.3 to 3.8 capsules Per plant when it was Planted with normally flowering tobacco with the average outcrossing of 7.2 plants, ranging from 2 to 18 out of 20 plants. With the farther the isolation distance between maternal plants and pollen donor plant, the lower the outcrossing occurred. Outcrossing occurred even at the isolation distance of 312 m. When the maternal plants were transplanted 35 days after transplanting the pollen donor ones, the outcrossed plants were not decreased significantly. The bagging of the flower head with the gauze-cloth bas (#0.9∼ 1.0 mm) decreased the outcrossed plants significantly, but couldn't prevent the outcrossing completely. The seed amount per plant was higher in the highly fertilized cultivation. The number of seed capsules per plant affected significantly on seed yield and quality. When the seed capsules was controlled by 30 or 50 capsules per plant, the weight of 1,000 seeds and germination rate were higher than those with 70 or 90 capsules per plant. Key words : Nicotiana tabacum, outcrossing, bagging.

• Korean Journal of Plant Tissue Culture
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• v.27 no.4
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• pp.299-307
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• 2000

A large amount of information is currently available for somatic embryogenesis of plants. However, one common problem related to somatic embryos is that the conversion rate can be low for some species. Apical meristems are responsible for post-embryonic growth of the embryo. The low percentage observed is most likely a result of poor apical meristem development or defects in the meristem organization during somatic embryogenesis. In flowering plants, apical meristems are well developed by the late heart stage of zygotic embryo development. In conifers, such as white spruce, apical meristems are formed at the pre-cotyledon stage. Thus, apical meristem development occurs very early, prior to the maturation stage of embryo development. Once formed, meristems are stably determined. In the somatic embryo, as exemplified by white spruce, since embryo development is not synchronous, tissue differentiation including apical meristem formation occurs throughout the“maturation”stage. Different apical meristem organizations can be found among different individuals within a population. In contrast to their zygotic counterparts, the apical meristems appear not to be stably determined as their organization, as the shoot apical meristem especially, can be easily modified or disrupted. Precocious germination seldom results in functional plantlets. All these observations suggest that the conditions for somatic embryo maturation have not been optimized or are not suitable for meristem formation and development. The following strategies could improve meristem development and hence conversion: 1. Simulate in ouuio conditions to promote meristem development prior to the“maturation”treatment.2. Prevent deterioration of apical meristem organization during somatic embryo maturation.3. Promote further meristem development during embryo germination.

• Journal of Plant Biotechnology
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• v.3 no.1
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• pp.27-31
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• 2001

New types of cytoplasmic male sterility in Brassica species would be very useful for the production of F$_1$, hybrid seeds. Leaves and stems of rapid cycling stock of B.juncea (CrGC4-3) containing Anand CMS were used as experimental materials for plant regeneration from protoplast culture. Very high plant regeneration rate (85%) was found in the Kao & Michayluk medium supplemented with 2 mg/L zeatin, 0.5 mg/L BAP, and 1 mg/L NAA when only leaf, not stem, segments were cultured. Protoplasts were isolated from leaves using mixtures of enzymes (1% Cellulycin, 0.5% Macerozyme) in 0.4 M mannitol and 50 mM $CaCl_2$.$2H_2$O. Mcrocalli induced from protoplasts were transferred to the shoot regeneration medium containing 2 mg/L BAP, 2 mg/L zeatin, and 0.5 mg/L NAA. After 60 days of initial protoplast culture, regenerated plantlets were obtained, acclimatized, transplanted into the pots, and grown up to the flowering stage.

• Journal of People, Plants, and Environment
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• v.23 no.2
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• pp.171-178
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• 2020

The present study was conducted to determine the effects of electron beam irradiation on the postharvest quality of cut flowers. Cut flowers were irradiated with electron beam at 100, 200, 400, 600, 800, 1,000, and 2,000 Gy with a 10 MeV linear electron beam accelerator to evaluate their irradiation tolerance. Postharvest quality was determined by monitoring fresh weight loss, flower longevity, flower diameter, flowering rate, visual quality of flowers and leaves, and chlorophyll content. Cut flowers showed a radiation-induced damage with increasing the irradiation dose. Flower longevity and fresh weight of cut flowers decreased when the irradiation dose was increased. Flower bud opening was also inhibited in a dose-dependent manner. The effective irradiation doses for 10% reduction of postharvest quality (ED₁₀) values were 144.4, 451.6, and 841.2 Gy in the 'Medusa' lily, 'Montezuma' carnation, and 'Rosina White' eustoma, respectively. Although tolerance of cut flowers to electron beam irradiation vary according to species, cultivars, or maturity stage conditions, it is conceivable that 'Montezuma' carnation and 'Rosina White' eustoma could be tolerated and maintained overall postharvest quality up to 400 Gy, the generic irradiation dose approved by the Animal and Plant Health Inspection Service (APHIS) and the International Plant Protection Convention (IPPC) for postharvest phytosanitary treatments.

• Horticultural Science & Technology
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• v.18 no.6
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• pp.792-796
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• 2000

The staking cultivation (SC) of oriental melon (Cucumis mela L. var. makuwa Mak.) produced more fruit yield than that of the conventional (creeping) growing. In the SC, preharvest fruit drop rate was high as 47.6% compared to 13.0% of the conventional cultivation. However, the foliar application of aminoethoxyvinylglycine (AVG, $100mg{\cdot}L^{-1}$) at 2 weeks after flowering (20 days before harvest) greatly reduced fruit drops up to 10.9% without causing any effects on ripening and quality of fruits . The AVG application markedly suppressed ethylene production in harvested fruits.

• Horticultural Science & Technology
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• v.29 no.2
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• pp.156-159
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• 2011

A new bright yellow gerbera (Gerbera hybrida Hort.), 'Sunmyo' was bred from a cross between red medium-gerbera 'Beauty' and yellow gerbera 'Tamara' in 2001. Characteristics trials were conducted three times from 2004 to 2006. Bred cultivar 'Sunmyo' showed bright yellow color (YG12B), black center, semi-double type, and middle size flower with stable flower shape. The average yield of 'Sunmyo' increased up to 37% (70.0 stems per year) as compared to control cultivar 'Biro' (51.0 stems per year). The vase life is 7.5 days. The survival rate is 85.0%, and days to first flowering are 95 in the plastic house passing the winter season.