• Journal of Plant Biotechnology
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• 제33권4호
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• pp.243-248
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• 2006

A optimal procedure for plant production via repetitive secondary somatic embryogenesis in Tilia amurensis is described. Somatic embryos were induced directly from the culture of zygotic embryos on medium with 1.0 mg/l 2,4.-D. Repetitive secondary somatic embryos formed on the surface of the cotyledons and hypocotyls except for the radicles when explants of somatic embryos were cultured on medium with 4.0 mg/l 2,4-D. The highest frequency of secondary embryo-genesis was obtained in the cotyledons (90%) and hypocotyls(83.33%) on MS medium with 1.0 mg/L 2,4-D. The average number of secondary embryos per explant was 25.74 in cotyledon and 24.92 in hypocotyl. When the cotyledon and hypocotyl segments from somatic embryos at different developmental stages were cultured on MS medium with 1.0 mg/L 2,4-D, the highest frequency of secondary embryogenesis was obtained from late cotyledonary secondary embryos. Somatic embryos were transferred to MS basal medium and then they germinated within 2 to 4 weeks of culture. Germinated somatic embryos grew normally into plantlets on WPM medium, producing new shoots. The converted plantlets were acclimatized on artificial soil mixture. These results indicate that the repetitive secondary somatic embryogenesis in T amurensis can offer the possibility to use in vitro culture system for the micropropagation.

• Journal of Plant Biotechnology
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• 제44권3호
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• pp.271-286
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• 2017

GROWTH-REGULATING FACTOR (GRF) genes encode plant-specific transcription factors containing two conserved QLQ and WRC domains and play critical roles in regulating the growth and development of lateral organs, such as cotyledons, leaves, and flowers. To explore the agricultural potential of Brassica rapa GRF genes (BrGRFs), the researchers isolated seven BrGRFs (BrGRF3-1, 3-2, 5, 7, 8-1, 8-2, and 9) and constructed BrGRF-overexpressing Arabidopsis thaliana plants (BrGRF-OX). BrGRF-OX plants developed larger cotyledons, leaves, and flowers as well as longer roots than the wild type. The increase in size of these organs were due to increases in cell number, but not due to cell size. BrGRF-OX plants also had larger siliques and seeds. Furthermore, BrGRF-OX seeds produced more oil than the wild type. RT-PCR analysis revealed that BrGRFs regulated expression of a wide range of genes that are involved in gibberellin-, auxin-, cell division-related growth processes. Taken together, the data indicates that BrGRFs act as positive regulators of plant growth, thus raising the possibility that they may serve as a useful genetic source for crop improvement with respect to organ size and seed oil production.

• Molecules and Cells
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• 제28권4호
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• pp.375-382
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• 2009

The 26S proteasome is a 2-MDa complex with a central role in protein turn over. The 26S proteasome is comprised of one 20S core particle and two 19S regulatory particles (RPs). The RPN12a protein, a non-ATPase subunit of the 19S RP, was previously shown to be involved in cytokinin signaling in Arabidopsis. To further investigate cellular roles of RPN12a, RNAi transgenic plants of RPN12a were constructed. As expected, the 35S:RNAi-RPN12a plants showed cytokinin signaling defective phenotypes, including abnormal formation of leaves and inflorescences. Furthermore, RNAi knock-down transgenic plants exhibited additional unique phenotypes, including concave and heart-shape cotyledons, triple cotyledons, irregular and clustered guard cells, and defects in phyllotaxy, all of which are typical for defective cytokinin signaling. We next examined the mRNA level of cytokinin signaling components, including type-A ARRs, type-B ARRs, and CRFs. The expression of type-A ARRs, encoding negative regulators of cytokinin signaling, was markedly reduced in 35S:RNAi-RPN12a transgenic plants relative to that in wild type plants, while type-B ARRs and CRFs were unaffected. Our results also indicate that in vivo stability of the ARR5 protein, a negative regulator of cytokinin signaling, is mediated by the 26S proteasome complex. These results suggest that RPN12a participates in feedback inhibitory mechanism of cytokinin signaling through modulation of the abundance of ARR5 protein in Arabidopsis.

• 한국초지조사료학회지
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• 제14권3호
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• pp.177-185
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• 1994

Slow seedling growth rate and nodulation failure of white clover (Trifolium repens L.) has been limited its good establishment to pastures. The experiment was done to determine the effect of removal of cotyledon and unifoliolate on the shoot, root growth, and nodule formation of 4 white clover cultivars for 8 weeks after the treatment. Four white clover cv. Regal (large leaf), Louisiana S-I (medium-large leaf), Grasslands Huia (mediumsmall leaf), and Aberystwyth S184 (small leaf), were grown in IOcm plastic pot containing 2:l:l soi1:sand:peat moss mixture until grown to cotyledon or unifoliolate stage and then removed one (Cl) or two cotyledons (C2) at cotyledon stage, and unifoliolate only (U), unifoliolate and one cotyledon (UCl) or unifoliolate and two cotyledons (UC2) at the unifoliolate stage, and the plants were sampled at 4, 6 and 8 weeks after the treatments. The intact plants had greater shoot and root dry weights, and no. of nodules than removal-treated ones. Removal treatments at cotyledon stage, the dry weight and no. of nodules more decreased in C1 and C2 than that of unifoliolate stage. While the severer cotyledon removal, the more reduction. Although the dry weights and no. of nodules steadily inclined with regrowing period, the former were higher in Regal and La. S-1 than in the others since 6 weeks after removal treatment but the latter was more in S 184 than in the others 8 weeks after removal treatment. Relationship between no. of nodules and shoot or root dry weight was analysed as linear mode while the earlier and severe removal, the steeper slope. It was concluded that severer damage of cotyledon and unifoliolate had detrimental effects on the shoot and root growth, nodule formation, and aftermath establishment of white clover.

• Journal of Plant Biotechnology
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• 제7권3호
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• pp.203-209
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• 2005

This study was conducted to improve tocopherol (vitamin E) composition in soybean (Glycine max) by introducing a gamma-tocopherol methyl transferase (${\gamma}$-TMT) gene via Agrobacterium tumefaciens-mediated transformation. Immature cotyledon explants were cocultivated with Agrobacterium tumefaciens. Putative transgenic embryos were selected from immature cotyledons on MS medium supplemented with 40 mg/L 2,4-D containing 100 mg/L kanamycin, 500 mg/L carbenicillin and 250 mg/L cefotaxime. Plantlets were developed from somatic embryos, and then transferred to soil. Nineteen regenerated plantlets obtained on the selection medium from 1,460 cotyledons. However, only 9 plantlets were confirmed as transformed plants. Integration of the transgene into the soybean genomic DNA was confirmed by PCR and Southern blot analysis. HPLC analysis showed that the content of ${\alpha}$-tocopherol in transgenic soybean seeds (AT-1) was approximately 4-fold higher than that of non-transgenic plants. Conclusively, we obtained the transgenic soybean having increased ${\alpha}$-tocopherol content by the overexpression of ${\gamma}$-TMT transgene.

• Journal of Plant Biology
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• 제35권3호
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• pp.219-227
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• 1992

지질성 종자(해바라기, 피마자, 잣나무)와 전분성 종자(완두, 옥수수)를 대상으로 배유와 자엽세포내의 저장지질의 형성, 분포 및 구조적 변화 등과 지질가수분해효소의 활성부위 및 세포내 분포양상 등을 세포화학적 방법을 이용하여 조사하였다. 채종후의 지질 및 전분성 종자의 배유와 저장성 자엽세포에는 구형의 단백과립과 지질소구인 스페로솜, 전분과립 등의 저장물질이 널리 분포하였으며 세포내소기관은 드물게 관찰되었다. 활면소포체에서 형성되어 방출된 소포들과 스페로솜의 초기 단계로 여겨지는, 전자밀도가 낮은 막성의 과립들은 염색상이 스페로솜의 그것과 동일하였다. 조면소포체에서 방출된 전자밀도가 높은 과립들은 원형질막의 인접부위에서 관찰되었다. 지질염색반응 결과, 일반적인 미세구조의 염색상과는 상이하게 단백과립내의 단백질보다는 구형의 스페로솜의 전자밀도가 높고 균일함이 확인되어 스페로솜의 주요 구성성분은 지질임을 알 수 있었다. 스페로솜과 활면소포체에서 방출하는 물질을 함유한 소포는 염색상이 동일하였다. 지질가수분해효소는 분해과정이 진행중인 스페로솜의 기질과 막 주변부, 그리고 원형질막 부근에서 강한 활성을 보였다.

• Journal of Plant Biology
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• 제39권1호
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• pp.41-48
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• 1996

발아 후 8일된 해녀콩 자엽에서 성질이 서로 다른 두 개의 homoserine dehydrogenase를 분리하였다. 자엽에서 얻은 조효소액을 열처리, 황산 암모늄 침전, DEAE-Sephacel 및 Sephacryl S-300 겔 크로마토그래피와 Procion red dye, Cibacron blue dye 및 Resource Q 컬럼 크로마토그래피로 정제하였다. 겔 크로마토그래피에서 얻은 2개의 활성분획 중 T-형(트레오닌 감수성)과 K-형(트레오닌 비감수성)의 분자량은 각각 230 kD과 135 kD이었다. 10mM 트레오닌 첨가로 T-형 효소는 70% 이상의 활성저해를 받았으나 K-형 효소는 전혀 억제를 받지 않았다. Homoserine에 대한 Km은 T-형이 1.6mM, K-형이 0.3mM이었고, NAD에 대한 Km은 T-형이 2.34mM, K-형이 0.03mM이었으며 NADP에 대한 Km은 두 효소에서 동일하게 0.01mM로 산출되었다. 400mM KCl에서 T-형은 4.9배, K-형은 2.8배의 활성증가를 보였다. 부분정체(Sephacryl S-300 겔 크로마토그래피)된 상태의 T-형과 K-형은 조건에 따라 쉽게 상호전환되었다.

• 한국자원식물학회지
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• 제33권6호
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• pp.666-674
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• 2020

Lotus (Nelumbo nucifera Gaertn.) is an economically important aquatic ornamental herb with multiple uses, including food, tea, natural pigments, and/or healthcare product. The objective of this study was to evaluate the physicochemical properties and antioxidant potential of lotus sprouts grown in three media: sprouting machine (LSSG), soil (LSSC), and mud (LSMC). The longest sprout was obtained in LSMC (4.79 and 26.79 cm) followed by LSSC (1.95 and 5.4 cm), and LSSG (0.60 and 2.85 cm) at 5 and 10 days, respectively. Higher amounts of total free amino acids were found in cotyledons (33.96, 21.45, and 38.90 mg/g) than in hypocotyls (15.77, 7.90, and 15.29 mg/g ) for LSSG, LSSC, and LSMC, respectively. The ratios of total essential to total non-essential amino acids were higher in hypocotyls (0.36, 0.31, and 0.46) than in cotyledons (0.34, 0.25, and 0.40), respectively. Similarly, the total polyphenol content of the hypocotyl of LSMC (50.33 ㎍ GAE/g) was the highest and that of the husk of LSSG (24.08 ㎍ GAE/g) was the lowest. Overall, the antioxidant potential of hypocotyl was higher than that of husk and cotyledon. The results indicated that the lotus sprouts grown in mud could be a good source of nutritional and natural antioxidants.

• 식물조직배양학회지
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• 제21권5호
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• pp.287-291
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• 1994

땅두릅에 있어서 이상체세포배의 형성에 미치는 ABA의 영향을 구명하기위하여 체세포배는 1.0 mg/L 2,4-D가 첨가된 M 기본배지상에서 자엽유래 배발생 세포괴로부터 유도되었다. 배발생세포괴에 0.2 mg/L의 ABA를 처리하여 3주간 배양한 후 ABA가 첨가되지않은 기본배지에 2주간 계속 배양한 경우에 2개의 정상적인 자엽수를 갖는 배는 68%. 생장조절물질이 첨가되지않은 MS 기본배지에 5주간 배양한 대조구에(59.4%) 비하여 높게 나타났다. 그러나 0.2mg/L의 ABA를 처리하여 3주간 배양한 후 ABA의 농도를 0.1 mg/L로 반감한 배지에서 2주간 배양한 경우에는 정상의 자엽을 갖는 배는 28.6%로 감소된 반면에 3개 이상의 자엽을 갖는 다자엽배의 형성률이 높게 나타났다. 구형배에 ABA를 농도별(0.01-1.0 mg/L)로 처리한 경우에 정상의 자엽을 갖는 배의 형성률은 농도에 비례하여 감소되었으며, 다자엽배의 형성률은 높게 나타났다. 또한 심장형, 어뢰형 및 자엽시기 등 배발생 단계별로 배에 ABA를 각각 상기와 같이 단기간 처리하거나 계속처리한 경우에도 다자엽배의 형성률은 높게 나타났다.

• 한국육종학회지
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• 제43권1호
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• pp.32-41
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• 2011

The objective of this study was to determine the fatty acid composition of newly developed tissues of germinated soybean seeds. Five soybean accessions with varied fatty acid composition were allowed to germinate in sand under greenhouse conditions. Seedlings were picked up after 4, 6, 8, 10 and 12 days of germination and freeze dried. The fatty acid composition of the newly developed tissues was analyzed by gas chromatography. Significant variation in fatty acid composition was observed between accessions, days of germination, and variety ${\times}$ day of germination in whole and the cotyledons. In the case of newly developed five tissues, significant variation in fatty acid composition were observed between days of germination except oleic acid for root, hypocotyl and epicotyl stem and except stearic acid for hypocotyl and unifoliate leaves while all the parameters were significantly different for accession. Significant interactions of accession and days of germination were observed for palmitic, linoleic and linolenic acid in all tissues; only for oleic acid in hypocotyl, epicotyl and unifoliate leaves; and only for stearic acid in root, hypocotyl, epicotyl and unifoliate leaves. During germination, the fatty acid composition of newly developed tissues changed dramatically but whole seedlings and cotyledons changed slightly. These tissues contained five major fatty acids as found in original seeds, but compositions were totally different from that of the seed: higher in palmitic, stearic and linolenic acid and lower in oleic and linoleic acid. New tissues conserved their fatty acid compositions regardless of genotypic variation in the original seeds.