• 한국산림과학회지
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• 제76권4호
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• pp.317-329
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• 1987

본(本) 연구(硏究)에서 한국산(韓國産) 녹나무과(科) 식물(植物) 6속(屬) 7종(種)의 뿌리와 줄기의 이기목부(二期木部)를 비교해부학적(比較解剖學的)으로 연구(硏究)하였다. 도관요소(導管要素) 및 목섬유(木纖維)의 직경(直徑)과 길이는 뿌리가 줄기보다 더 넓고, 더 길었다. 계단상(階段狀) 천공판(穿孔板)을 갖는 도과요소(導管要素)의 말단벽(末端壁) 각도(角度)나 횡대수(橫帶數)는 줄기에 비해 뿌리가 더 사각(斜角)이고 다수(多數)였다. 방사조직(放射組織)의 폭(幅)과 높이는 뿌리에서 줄기보다 넓고 높았다. 이런 특징(特徵)들은 계통발생적(系統發生的)인 면(面)에서 볼 때, 도관요소(導管要素)의 직경(直徑)을 제외(除外)한 대부분의 형질(形質)들은 뿌리가 줄기보다 더 원시적(原始的)인 경향(傾向)을 보인다.

• Plant Biotechnology Reports
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• 제5권1호
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• pp.1-7
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• 2011

Secondary walls have recently drawn research interest as a primary source of sugars for liquid biofuel production. Secondary walls are composed of a complex mixture of the structural polymers cellulose, hemicellulose, and lignin. A matrix of hemicellulose and lignin surrounds the cellulose component of the plant's cell wall in order to protect the cell from enzymatic attacks. Such resistance, along with the variability seen in the proportions of the major components of the mixture, presents process design and operating challenges to the bioconversion of lignocellulosic biomass to fuel. Expanding bioenergy production to the commercial scale will require a significant improvement in the growth of feedstock as well as in its quality. Plant biotechnology offers an efficient means to create "targeted" changes in the chemical and physical properties of the resulting biomass through pathway-specific manipulation of metabolisms. The successful use of the genetic engineering approach largely depends on the development of two enabling tools: (1) the discovery of regulatory genes involved in key pathways that determine the quantity and quality of the biomass, and (2) utility promoters that can drive the expression of the introduced genes in a highly controlled manner spatially and/or temporally. In this review, we summarize the current understanding of the transcriptional regulatory network that controls secondary wall biosynthesis and discuss experimental approaches to developing-xylem-specific utility promoters.

• Journal of Applied Biological Chemistry
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• 제51권3호
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• pp.83-87
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• 2008

Tension wood, a specialized tissue developed in the upper side of the leaning stem and drooping branches of angiosperm, is an attractive experimental system attractive for exploring the development and the biochemical pathways of the secondary cell wall formation, as well as the control mechanism of the carbon flux into lignin, cellulose, and hemicellulose. However, the mechanism underlying the induction and the development of the tension wood is largely unknown. Recently, several researchers suggested the possible roles of the plant growth hormones including auxin, gibberellin, and ethylene mainly based on the expression pattern of the genes in this specialized tissue. In addition, expressed sequence tag of Poplar and Eucalyptus provide global view of the genetic control underlying the tension wood formation. However, the roles of the majority of the identified genes have not yet been clearly elucidated. The present review summarized current knowledge on the biosynthesis of tension wood to provide a brief synopsis of the molecular mechanism underlying the development of the tension wood.

• Journal of Ginseng Research
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• 제28권3호
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• pp.149-156
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• 2004

The objectives of this study were to investigate the morphology of mycorrhizal roots, and the effects of root age and soil texture on the mycorrhizal infection in ginseng (Panax ginseng C. A. Meyer) growing in Korea. Ginseng roots at ages of two to six years were collected from fields in late June. Their infection by arbuscular mycorrhizal fungi(AMF) was studied by clearing the roots and staining fungal hyphae with trypan blue. Root infection varied greatly depending on the developmental stages of young roots. Young tertiary roots, in diameter of smaller than 0.8 mrn, formed during the current growing season had root hairs and were frequently and in some cases heavily infected by AMF. Hyphal coils and arbuscules were abundant, while vesicles were rarely observed. Older secondary or tertiary roots in diameter of bigger than 1.0 mm with fully differentiated primary xylem formed during the previous growing season had no root hairs, and were not infected at all. The rates of mycorrhizal infection in the young tertiary roots were not affected by the age of the ginseng plants, suggesting that fungal populations might have not much changed during the aging of the cultivated fields up to six years. The differences in the infection rates among the different ages of ginseng were caused by differences in the amount of young tertiary roots in the samples. Soil texture, either sandy loam or clay loam, did not affect the rate of root infection. There were large variations in the infection rates among the different farms and locations within a farm. It strongly suggested that infection rates of the ginseng roots by AMF would be influenced by the practice of the farmers, possibly by avoiding consecutive planting, introduction of new topsoil, and the ways of handling the soil before transplanting the ginseng, such as fumigation or sterilization that might have affected indigenous inoculum sources of the AMF.

• Journal of Plant Biotechnology
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• 제3권3호
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• pp.131-134
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• 2001

In $\lambda$-Zap II vector system, a cDNA library was constructed for the developing secondary xylem mRNA from hybrid poplar, Populus nigra x maximowiczii. A cDNA clone of 1.5 kb in size, pOMTB1.4 encoding a lignin-bispecific O-methyltransferase was screened by plaque hybridization using a probe of 540 bp cDNA amplified by polymerase chain reaction from the cDNA library and identified by nucleotide sequencing. Its nucleotide sequence contains one open reading frame of 366 amino acids. The deduced amino acid sequence in comparison with that of Populus tremuloides showed the differences of 9 amino acids and revealed 85-99% homology among alfalfa, poplar and aspen.

• Applied Microscopy
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• 제17권1호
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• pp.161-168
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• 1987

The elongated filamentous haustorial cells, hyphae, of Cuscuta australis R. Brown penetrated into the vascular tissues of the host plant Trifolium repens L. were studied by the light and electron microscopes. The hyphae reached the host xylem were invaded into the host vessels and then they grew within the host vessels. Finally these hyphae were differentiated into the water conducting elements, xylary hyphae, by thickening of the secondary walls. The hyphae reached the host phloem were branched at the apical regions. These hyphae possessed thin-layered cytoplasm involving the typical features of sieve elements such as the parallel arrays of smooth endoplasmic reticulum, plastids with the clusters of fine starch granules, and mitochondria with the dilated cristae. It was indicated that these hyphae were differentiated into the nutrients conducting elements, phloic hyphae. The structures described were compared with those of other parasitic plants and were discussed in view of the translocation of materials from host to parasite.

• Journal of Plant Biology
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• 제28권4호
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• pp.271-284
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• 1985

Anatomical characters of secondary xylem in the trunk of Magnoliaceae, Winteraceae and Schizandraceae, including six genera and eleven species grown naturally in Korea, were studied to elucidate the relationship between genera or families. It is considered that among these families specialization in the perforation plate, the angel of end wall to the vessel axis, and diameter of vessel element, is in the order of Winteracae, Magnoliaceae, and then Schizandraceae. In Winteraceae, vessel elements have wholly scalariform perforation plates with very numerous bars. Among Magnoliaceae the peroration plates are scalariform with very numerous bars in Michelia, with few bars in Liriodendron, and with few bars or simple in Magnolia. In Schizandraceae, Schizandra shows scalariform perforation plates with few bars or simple perforation plates, and Kadsura shows almost simple ones.

• Journal of Plant Biology
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• 제27권2호
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• pp.81-94
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• 1984

Anatomical features and cell dimensions of the secondary xylem in the stem of the korean Lauraceas including 6 genera and 12 species were investigated under a light microscope and scanning electron microscope. Key to identification among genera or species was made from the anatomical features and systematic correlation investigated. The stem woods of Lauraceae exhibit the following characters: (1) quite evenly distributed pores (diffuse-porous wood) (2) perforation plates simple or occasionally scalariform in the latewood vessels (3) almostly 2-seriate and heterocellular rays (4) abundant paratracheal-vasicentric parenchyma (5) oil cells. Especially, the appearance of simple perforation plates suggest the Lauraceae to be more or less advanced. It is considered that the series of specialization in the Lauraceae from the perforation plates and the height of rays is as LinderalongrightarrowNeolitsealongrightarrow(Machilus, Litsea, Iozoste)longrightarrowCinnamomum, and Lindera sericea is the most pribitive in the Lauraceae.

• 한국작물학회지
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• 제37권2호
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• pp.155-165
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• 1992

본 실험은 수도이삭줄기의 유관속 발육을 증진시켜 수량을 증가시킬 수 있는 방안을 모색하기위하여 1989-1990년에 국제벼연구소(IRRI)에서 인도형인 IR58과 인본형인 Unbong 7을 공시하여 실시하였다. 1. 주간의 절간위치별 유관속수는 상위로부터 제1절간(수수절간)은 제 2,3,4,5절간에 비해 현저하게 적었으며, 품종별로는 IR58이 Unbong 7보다 많이 발육되었다. 2. 수수절간의 유관속수 및 횡단면적은 주간이 1,2차 분얼경보다 많이 컸으며, 분얼의 발육순서에 따라 저하되는 경향이었고, IR58은 Unbong 7보다 대유관속의 수와 횡단면적이 많이 컸으나 소유관속은 적고 작았다. 3. 양분의 이동통로인 사부와 수분의 이동통로인 본부의 횡단면적도 분얼의 출현이 빠른 것이 늦은것보다 크게 발육되어 있어서 출현이 빠르게 분얼경이 양수분흡수 및 동화물질의 전류에 유리한 특성을 가지고 있는 것을 사료되었다. 4. 이삭당 수중 및 수량은 주간에서 가장 높았고, 1차분얼 2차분얼의 순서로 낮아지는 경향으로 분얼경의 출현순서와 밀접한 관련성을 가지고 있었다. 5. 수수절간의 대유관속수는 이삭형질인 1,2차 지경수와 유의한 정의 상관관계를 나타냈으며, 이는 대유관속이 지경수 및 영화수 분화에 직접적인 영향을 준 것으로 해석되었다. 6. 일찍 출현된 분얼경은 늦게 출현된 분얼경에 비해 비교적 긴 생육기간을 가지고 있었으며, 양호한 유관속의 발육, 굵은 수수직경, 영화수 분화 및 등숙율을 향상시키고 나아가서 수량이 많아지는 특성을 나타냈다.

• 한국약용작물학회지
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• 제8권4호
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• pp.297-303
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• 2000

Paeonia lactiflora Pallas와 Paeonia obovata Maxim.의 뿌리와 줄기를 식물 해부학적으로 살펴본 결과 도관절의 길이에 있어서는 P. lactiflora Pallas가 P. oboata Maxim. 보다 줄기 및 뿌리에서 다소 길게 나타났으며 도관절의 폭에 있어서도 P. lactiflora Pallas가 P. oboata Maxim.의 줄기와 뿌리에 비해 넓게 분화된 양상을 관찰 할 수 있었다. P. lactiflora Pallas의 뿌리에서 이기목부(二期木部)는 불연속적인 층상배열을 이루나 P. oboata Maxim.에서는 연속적인 방사열을 이루어 종간의 뚜렷한 차이를 나타냈다.