• Horticultural Science & Technology
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• v.29 no.4
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• pp.326-335
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• 2011

When bougainvilleas are subjected to indoor low-light conditions, flower bracts regularly abscise. This study elucidates the effects of plant growth regulators on bract longevity of potted bougainvillea. Potted 'Taipei Red' bougainvillea in four different bract development stages were treated with 1-MCP (1-methylcyclopropene), NAA (1-naphthaleneacetic acid), SNA (sodium salt of naphthaleneacetic acid), IBA (indolebutyric acid), BA (6-benzylaminopurine), $KH_2PO_4$ (potassium dihydrogen phosphate), Put (diamine putrescine), SA (salicylic acid), or STS (silver thiosulfate) and were moved to indoor low-light conditions after treatments. Experimental results indicate that 1-MCP, NAA, SNA, BA, Put, and SA prolonged bract longevity, and this effect increased as bract stage increased. The effect of STS was significant in early bract stages and decreased as bract stages increased. Additionally, 1-MCP, NAA, SNA, BA, Put, SA, and STS treatment significantly reduced endogenous ACC (1-aminocyclopropene-1-carboxylate) content and ACC oxidase activity, suggesting that the inhibition of ethylene production was achieved via physiological metabolism. However, treatment with IBA or $KH_2PO_4$ had no effect on the bract longevity at any stage. In the combined chemical treatments, NAA + STS or NAA + SA were effectively for prolonging bract longevity and contained less protein or chlorophyll degradation, decrease ACC oxidase or ethylene production than the control. In conclusion, we propose that combined chemical treatment significantly prolonged the bract longevity and more effectively than single chemical treatment at any stage.

• Journal of Biosystems Engineering
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• v.35 no.3
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• pp.163-168
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• 2010

With income growth and "well-being" trends, sales of corn has been increased recently. Corns are processed at processing facilities on the main production site. Corn processing steps include removing bract, steaming, vacuum packing, and storing. To replace manual corn bract removing, some bract removing machines were imported and used. However, the machines were abandoned shortly, because of high damaging ratio of corns. In this research, factors of successful bract removing was studied with rotating rollers and air-injection nozzles to develop corn bract removing system. The test device was composed of a cylindrical roller, an air spray nozzle, a regulator, and a motor. Designing factors were roller type, diameter of air spraying nozzle, spraying angle, and spraying pressure. The measured factors were bract removing rate and damaging rate. It was found that optimum cylindrical roller surface shape was cylindrical roller and linear grove roller. This roller shape produced lowest damaging rate. Test results of the efficacy of preprocessing showed that the air spraying after preprocessing produced highest performance. The rotational speed and inclination of the roller didn't affect the bract removing performance. Optimum injection angle of the air jet nozzle was $70^{\circ}$. To increase bract removing rate and to reduce corn damage, required injection pressure and injection nozzle diameter were decided to less than 0.4 MPa and 2.5 mm, respectively. More than 3 times of nozzle passing produced good bract removing performance and there were no significant difference between the number of passing times.

• Journal of Korean Society of Forest Science
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• v.97 no.6
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• pp.565-569
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• 2008

Geographic variation of characteristics of cone, seed and bract morphology were examined in 8 populations of rare endemic Abies nephrolepis (Trautv.) Maxim and A. koreana Wilson. Additionally we studied classification index to distinguish between the species by the method of discriminant analysis. Nested ANOVA showed that there were statistically significant differences among populations as well as among individuals within populations in all 13 morphological traits. In the seed length, seed index, bract width, and bract index of A. nephrolepis and the bract width and index of A. koreana, variance components among populations were larger than those among individuals within populations. In discriminant analysis, three traits (cone width, length of seed wing, and bract length) were found to be useful in discriminating A. nephrolepis from A. koreana. The optimal classification results of stepwise selection were discriminated length of seed wing and bract length.

• Horticultural Science & Technology
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• v.32 no.5
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• pp.623-627
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• 2014

Curcuma alismatifolia is becoming popular for cut flowers and potted plants due to its long inflorescence with many showy pink flowers. It is propagated by rhizomes and inflorescences that are similar to those of lotus. However, initiation of inflorescence development of each bract and flower has not been investigated. Therefore, this experiment was conducted to study the inflorescence development of Curcuma alismatifolia 'Chiangmai Pink' by scanning electron microscopy (SEM). When new shoots grew to 15-20 cm in a greenhouse at $25^{\circ}C$, the first bract initiated with a dome-shaped inflorescence apex, followed by initiation of additional bracts, forming the shape of the flower head. Florets were subtended by the first bract when five to seven bracts were formed. Four to six florets were subtended by each bract. The floret positioned in the center initiated and progressed upward first. When the center florets in the upper bracts were formed, florets next to the center floret subtended by the first bract were formed, and formation of the axillary florets progressed upward in sequential order.

• Journal of Plant Biology
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• v.36 no.2
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• pp.141-149
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• 1993

Comparative morphology of winter buds of 16 species of gymnosperms which belong to six families and 13 genera was investigated. All the species examined except Taxaceae had bracts and ovuliferous scales in female buds, and the bract was fused with ovuliferous scale in various degrees. Comparison of the modern conifers with fossil ones in the position of ovule and structure of bract-scale complex suggested that Taxaceae should be placed in Coniferales, rather than treating as a distinct order. The disposition of bract surrounding the ovules of Cephalotaxus and Torreya indicated that the origin, of ovules had separate evolutionary line in spite of similar structure of female bud. The shape of microsporophyll in male bud was diverse among the species. The dehiscence of microsporangium was transverse in Abies and Tsuga, while longitudinal in other species. Descriptions and key to the species based on bud morphology were provided.

• Korean Journal of Breeding Science
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• v.42 no.6
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• pp.717-720
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• 2010

A new cultivar of Euphorbia milii, 'Panorama' was developed at Cactus Research Institute, Gyeonggi-do Agricultural Research & Extension Services in 2009. 'Gabi' and 'Maxi' were crossed in 2001 and three $F_1$ seedlings were obtained. Pedigree selection was performed in 2002. One line was finally selected and named as 'Panorama' through the test of specific character from 2007 to 2009. The new cultivar 'Panorama' has green and pink colored bract, and it has 2~3 each of inflorescence number, 2.0 cm of bract width, 4.3 each of lateral shoot and 14.9 cm of plant height. Characters of the cultivar can be maintained by vegetative propagation.

• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.122-132
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• 2023

The external morphological characters of six taxa of the genus Melampyrum in Korea (M. roseum, M. roseum var. japonicum, M. roseum var. ovalifolium, M. setaceum, M. setaceum var. nakaianum, and M. koreanum) were observed to identify the taxonomic entity. The taxonomically useful characters, confirmed in this study, were as follows; the shape of leaf and bract, the number and location of the setose teeth at bract margin, the shape of cross-section and distribution of hair on the stem, the shape of bract base, the shape and protuberance type of calyx lobes, the color and length of the corolla, and the shape of the capsule. Based on these results, a key to the Korean Melampyrum taxa is provided.

• Journal of Bio-Environment Control
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• v.13 no.2
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• pp.107-111
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• 2004

This study was conducted to examine the possibility of producing poinsettia with various growing media containing used perlite and rockwool slabs as medium components. Pot plants of Euphorbia pulcherrima 'Freedom Red' were grown in 10 media containing used perlite and particles of rockwool slabs at various ratios including 1:1 and 1:3 (v/v). Medium containing used perlite and peatmoss at 1:3 (v/v) was employed as the control treatment. Height, root length, length of the longest branch, number of roots, leaf area, and width and length of the largest bract of plants grown in media containing used perlite were significantly greater than those in the control. Stem diameter and bract count were not affected by the medium composition. From the results, used perlite and rockwool slabs were proved to be a practically useful materials as medium components for pot production of poinsettia plants.

• Journal of Plant Biology
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• v.32 no.3
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• pp.163-172
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• 1989

Nerium indicum has adaxial colleters on each petiole, bract, bracteole, calyx and corolla. The colleters are finger-shaped sometimes lobed structures with tall heads on short stalks. The petiolar colleters are more abundant than those on the bract, bracteole, calyx and corolla but their structure is similar. Meristematic activity in a small group of protodermal and hypodermal cells at the base of the developing leaf gives rise to the colleter that further differentiates by frequent anticlinal and periclinal divisions. Many of the colleters are vascullarized, sometimes a layer of redially elongated cells is present beneath the epithelial cells. Senescence of a colleter begins when the leaves have either completed their growth or are still expanding. In senescent colleters, the central cell cytoplasm and nuclei are considerably reduced. Thin layer chromatography of the freshly harvested exudate of colleter shows the presence of rhamnose, glucose and arabinose sugars.

• Korean Journal of Plant Taxonomy
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• v.32 no.3
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• pp.257-292
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• 2002

Morphological characters of sections Foetidae(one taxon), Arenariae(one taxon) and Multiflorae(six taxa) of genus Carex(Cyperaceae) were reexamined. The epidermal patterns of perigynium, achene and leaf were investigated using by a scanning electron microscope(SEM) and a light microscope(LM). Morphological characters, such as length and width of stem, leaf, leaf sheath, bract, spike, scale, perigynium and beak of perigynium, length of spike peduncle, size and frequency of stomatal complex of leaf, number of bract, shape of stem transection, scale and apex of scale, beak and base of perigynuim, achene, epidermal cell and cell wall of perigynium, achene, leaf epidermal patterns(fundamental epidermal cell and cell wall, silica body, subsidiary cell), hair, papillae present/absent of perigynium, and leaf were useful for the identification of observed eight taxa. According to the current study, examined eight taxa of sections Foetidae, Arenariae and Multiflorae were distinct from each other with respect to length and width of stem, leaf, bract, perigynium, perigynium beak, length of spike peduncle, shape of bract, scale and apex of scale, perigynium, perigynium beak, hair presence/absence of perigynium and leaf. A key based on data was presented here.