• Journal of Plant Biology
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• 제31권4호
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• pp.289-298
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• 1988

The pattern of elongation in the developing hypocotyl of Glycine max shows that the elongation generally proceeds from base to the cotyledonary node in acropetal diredtion, although earlier elongation takes place through the entire hypocotyl. Because the differentiation of the vascular cambium in the hypocotyl advances also acropetally, it can be seen that the acropetal wave of hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl elongation is associated with the acropetal differentiation of the cambium in the hypocotyl. The elongation of procambial cells occurs not only during active elongation but also after cessation of elongation of the hypocotyl. In tangential view, the procambium of the hypocotyl in early stage has homogeneous structure composed of short cells. Subsequently, these procambial cells elongate actively and then become elongated long cells. These long cells eventually become fusiform initials, while some of elongated long cells are transversely divided and then converted into ray initials. The characteristics of the vascular cambium are entirely acquired some time after hypocotyl elongation is completed, and the transitin from procambium to vascular cambium in the hypocotyl is a rather gradual process.

• Journal of Plant Biology
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• 제34권4호
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• pp.274-281
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• 1991

The relationship between elongation of hypocotyl and its vascular transition was studied with seedling of Glycine max. the hypocotyl elongation proceeded acropetally from the base of hypocotyl toward the cotyledonary node. The vascular transition did not occur in the basal region of the hypocotyl, which did not nearly elongate, with exarch radial vascular bundles. However, the vascular transition was almost completed at the middle part of the hypocoty, more or less elongated, with endarch collateral vascular bundles. Such bundles also appeared in the uppermost region of the hypocotyl, in which the elongation was the most striking. These results suggested that the vascular transition was related to the hypocotyl elongation and that the transition of primary vascular system in Glycine max seedling was established by rather rapid process. Our observations of the serial sections from root to hypocotyl revealed that the vascular system through the root-hypocotyl-cotyledon was a unit, to which one of the epicotyl that did not participate in transition was superimposed.

• Molecules and Cells
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• 제45권4호
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• pp.243-256
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• 2022

Transcriptional regulation, a core component of gene regulatory networks, plays a key role in controlling individual organism's growth and development. To understand how plants modulate cellular processes for growth and development, the identification and characterization of gene regulatory networks are of importance. The SHORT-ROOT (SHR) transcription factor is known for its role in cell divisions in Arabidopsis (Arabidopsis thaliana). However, whether SHR is involved in hypocotyl cell elongation remains unknown. Here, we reveal that SHR controls hypocotyl cell elongation via the transcriptional regulation of XTH18, XTH22, and XTH24, which encode cell wall remodeling enzymes called xyloglucan endotransglucosylase/hydrolases (XTHs). Interestingly, SHR activates transcription of the XTH genes, independently of its partner SCARECROW (SCR), which is different from the known mode of action. In addition, overexpression of the XTH genes can promote cell elongation in the etiolated hypocotyl. Moreover, confinement of SHR protein in the stele still induces cell elongation, despite the aberrant organization in the hypocotyl ground tissue. Therefore, it is likely that SHR-mediated growth is uncoupled from SHR-mediated radial patterning in the etiolated hypocotyl. Our findings also suggest that intertissue communication between stele and endodermis plays a role in coordinating hypocotyl cell elongation of the Arabidopsis seedling. Taken together, our study identifies SHR as a new crucial regulator that is necessary for cell elongation in the etiolated hypocotyl.

• Plant Resources
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• 제2권1호
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• pp.10-15
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• 1999

In vitro shoot regeneration from cotyledon and hypocotyl explants derived from germinating mature Impatiens seeds. The induction of organogenetic tissue was also influenced by the cotyledon and hypocotyl. Multiple shoot induction was higher in hypocotyl than in the cotyledon explant with Thidiazuron and a NAA medium.

• 한국작물학회지
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• 제37권1호
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• pp.68-77
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• 1992

대두재배에 있어서 단위면적당 주수를 결정하기 때문에 수량에 직접적인 영향을 미치는 것으로 알려진 출아ㆍ입묘에 대한 기초연구의 일환으로 한국 대두 장려 품종들에 대한 하배축신장성 및 출아에 대한 조사를 하였던 바 그 결과를 요약하면 다음과 같다. 1. 하배축신장은 파종 후 3.0-3.5일 사이에 가장 왕성하였으며 하배축신장성이 ＆apos;양호＆apos;한 품종은 은하콩, 장경콩, 보광콩, 등 3품종이었고, ＆apos;중＆apos; 품종은 남해콩, 단경콩, 단엽콩, 밀양콩, 덕유콩, 팔달콩, 망운조생, 남해콩, 새알콩, 등 9품종 이었고 ＆apos;불량＆apos;했던 품종은 광교, 백운콩, 장백콩 등 3품종이었다. 2. 같은 품종에 있어서 종자크기별 하배축신장은 종자크기와는 반대로서 소립, 중립 및 대립 순으로 종자크기가 작을수록 오히려 하배축신장이 양호하였다. 3. 100입중과 하배축신장성과의 관계는 r=-0. 2506$^{**}$ 으로 100입중이 클수록 하배축신장성은 오히려 저조하였다. 4. 처리온도가 높을수록 하배축신장은 양호하였고, 낮을수록 저조하였는데 우리나라 대두의 하배축신장에는 30-35$^{\circ}C$가 적온이었다. 또한 처리온도 $25^{\circ}C$에서 특이하게 하배축신장이 억제되었던 품종은 발견할 수 없었다. 5. G $A_3$는 처리농도가 높을수록 하배축신장을 촉진하였고, ABA, Kinetin및 BA는 처리농도가 높을수록 하배축신장을 억제하여 서로 상반되는 .반응을 보였는데 그 정도는 하배축신장이 큰 품종에 비해 작은 품종에서 뚜렷하였다. 6. 습윤ㆍ고온처리에 의한 종자노후화 정도는 하배축신장이 양호하였던 품종이 불량하였던 품종보다 노후화 속도가 느려 습윤ㆍ고온처리를 하였을 때도 하배축신장이 뚜렷하게 컸다.

• 한국작물학회지
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• 제41권6호
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• pp.634-639
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• 1996

근래에 육성된 한국산 녹두품종에 대하여 용도상 분류 기준이 되는 하배축신장성과 주요 성분함량을 조사하여 품종 육성의 기초 자료로 활용하고자 수행하였던 바 그 결과를 요약하면 다음과 같다. 1. 하배축 신장성이 큰 품종은 4234-697과 금성녹두였으며 남평녹두는 중간정도, 선화녹두는 작았다. 2. 파종 후 치상온도가 높을수록 하배축 신장은 양호하였는데 고온에서는 파종직 후부터 급속한 신장을 나타냈다. 3. 냉장고에 저장한 종자의 하배축신장성은 상온에 저장한 종자보다 하배축신장성이 양호하였다. 4. 종자크기와 하배축신장성과는 품증에 따라 각각 다른 상관정도를 보였으나 유의성은 인정되지 않았다.

• 원예과학기술지
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• 제35권4호
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• pp.402-409
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• 2017

We performed seed germination tests to investigate the effects of seed sowing orientation on germination viability on peanut (Arachis hypogaea L.) sprouts. Specifically, we assessed the influence of seed sowing orientation on germination rate, seedling weight, and seedling length, as well as the seedling vigor index. The seeds were sown in oak tree sawdust at 3.0 cm depth. Four seed orientations were tested: vertical with the hypocotyl end down, vertical with the hypocotyl end up, horizontal with the hypocotyl end down, and horizontal with the hypocotyl end up. The mean seed germination percentages of the four seed orientations were significantly different (p < 0.01) and ranged from 25 to 91.7%. The vertical orientation with hypocotyl-end-down and hypocotyl-end-up orientations showed the highest (91.7%) and lowest (25%) germination rates, respectively. The vertical orientation with the hypocotyl end down produced the heaviest (4.9 g) seedlings and the longest hypocotyls (4.65 cm). This orientation also produced the longest true leaf + epycotyl (2.15 cm) and had the highest seedling vigor index (197.1). The seedlings had a straight growth pattern, whereas seedlings from seeds sown with the hypocotyl up had an awkward plumular hook shape. Taken together, to produce peanut sprouts, we recommend placing the seeds vertically with the hypocotyl end down because this orientation leads to a high germination rate, high biomass production, and high overall seedling quality.

• 환경생물
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• 제21권3호
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• pp.245-250
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• 2003

Composition of isoflavone in cotyledon and hypocotyl of soybean were detected using HPLC. Optimum conditions for extracting isoflavone from hypocotyl were studied as well. Contents of isoflavone in soybean cotyledon and hypocotyl were 482.5 mg 100 $g^{-1}$ and 3453.3 mg 100 100 $g^{-1}$, respectively. Hypocotyl contained 7~8 times move isoflavone than corresponding cotyledon of the soybean. Malonyl glycoside accounted for move than 70% of the total isoflavone, followed by glycoside, acetyl glycoside, and aglycone. Aqueous ethanol of 60~80% was the most suitable solvent for extracting isoflavone from the hypocotyl. Optimum temperature and time was $90^{\circ}C$, 1hr. Acetic acid, NaCl, and NaOH added to 80% ethanol suppressed extraction yield of the phytochemieal.

• Journal of Photoscience
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• 제9권2호
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• pp.94-97
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• 2002

Light is one of the most important environmental factors that influence plant growth and development. It does not function independently but exerts its role through coordinated interactions with intrinsic developmental programs, such as hormonal regulation. One typical example is hypocotyl growth in which light signals are modulated through growth hormones. However, the underlying molecular mechanisms are largely unknown. We demonstrated that brassinosteroids play an important role in the light signal transduction in etiolated hypocotyl growth. A light-responsive Ras-like G-protein, Pra2 from pea, physically and functionally interacts with a cytochrome P450 that specifically catalyzes C-2 hydroxylation in brassinosteroid biosynthesis. The cytochrome P450 expression, along with Pra2, is induced in the dark and predominantly localized in the rapidly elongating zone of etiolated pea epicotyls. Transgenic plants with a reduced level of Pra2 exhibit a dark-specific dwarfism, which is completely rescued by brassinosteroid application. On the contrary, overexpression of the cytochrome P450 results in enhanced hypocotyl growth even in the light, which phenocopies the etiolated hypocotyl growth. It is therefore envisioned that Pra2 is a molecular switch that mediates the crosstalk between light and brassinosteroids in the etiolation process.

• 한국작물학회지
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• 제46권5호
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• pp.375-379
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• 2001

Transgenic plants from hypocotyl segments of buckwheat were produced with the Agrobacterium strain LBA4404 harboring the binary vector pBI121 containing chimeric genes of neomycin phosphotransferase II (npt II) and $\beta$-glucuronidase (gus). Two weeks after co-cultivation with Agrobacterium, most of the hypocotyl segments gradually became brown and died on the selection medium containing 100mg/$\ell$ of kanamycin. Plants regenerated from the hypocotyl explants grown on selection medium were GUS-positive in the leaf, stem and vascular tissues by histochemical assay, and varied in gus activity (440-2568 pmol, 4-MU/mg protein) by fluorimetry. The plants showing GUS activity were confirmed of containing GUS and NPT-II genes by polymerase chain reaction (PCR). Within 3 months, transgenic buckwheat plants were able to obtained from the hypocotyl segments.