• ALGAE
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• v.19 no.3
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• pp.175-190
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• 2004

The morphological and molecular characteristics of Pachydictyon coriaceum (Holmes) Okamura (1899) are described. Plants are collected from Korea all year round and have maximum height from August to September. The monthly variability of thallus growth is in the way with that of the seawater temperature. Two types of thallus structures, thick cortical layer tallus type and thin cortical cell layer type, are distinguished according to growing seasons. The habit of Korean plants is also classified into two thallus types, slender type and wide type, based on the length and the width of internodes, but this distinction between two types is not supported by either anatomical or molecular characteristics. P. coriaceum shares typical morphology in branching pattern and morphogenetic processes with the other species of Dictyota: 1) multi-cellular cortical and medullar layer in the partial of thallus, 2) same development of thallus from apical meristem cell, and 3) sub-lineage within Dictyota species lineage in rbcL, psaA and psbA gene sequences analyses. These characteristics lead to propose the new combination of Dictyota coriacea (Homes) I.K. Hwang, H.S. Kim et W.J. Lee, comb. nov.

• Proceedings of the Botanical Society of Korea Conference
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• 1985.08b
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• pp.35-48
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• 1985

Plastids, which are organelles unique to plant cells, bear their own genome that is organized into DNA-protein complexes (nucleoids). Regulation of gene expression in the plastid has been extensively investigated because this organelle plays an important role in photosynthesis. Few attempts, however, have been made to characterize the regulation of plastid gene expression at the chromosomal structure, using plastid nucleoids. In this report, we summarize the recent progress in the characterization of DNA-binding proteins in plastids, with special emphasis on CND41, a DNA binding protein, which we recently identified in the choloroplast nucleoids from photomixotrophically cultured tobacco cells. CND41 is a protein of 502 amino acids which consisted of a transit peptide of 120 amino acids and a mature protein of 382 amino acids. The N-terminal of the 'mature' protein has lysine-rich region which is essential for DNA-binding. CNA41 also showed significant identities to some aspartyl proteases. Protease activity of purified CND41 has been recently confirmed and characterized. On the other hand, characterization of accumulation of CND41 both in wild type and transgenic tobacco with reduced amount of CND41 suggests that CND41 is a negative regulator in chloroplast gene expression. Further investigation indicated that gene expression of CND41 is cell-specifically and developmentally regulated as well as sugar-induced expression. The reduction of CND41 expression in transgenic tobacco also brought the stunted plant growth due to the reduced cell length in stem. GA3 treatment on apical meristem reversed the dwarf phenotype in the transformants. Effects of CND41 expression on GA biosynthesis will be discussed

• Journal of Plant Biology
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• v.22 no.1_2
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• pp.35-43
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• 1979

The present investigation has been made to study the deficiency symptoms of boron on the formation of cell wall and the development of the individual components of the orchid cell wall. Analytical samples were taken from two sources; one from the individual orchid plants started from an apical meristem culture followed by the generation of the protocorm-like body which was developed into a plant, the other from the plant cultivated in water for 30 days. The amount of boron in the cultrues were controlled and the deficiency symptoms were observed under theelectron microscope, optical microscope with samples taken from the zones of elongation of leaves and compared the dry weight of cell walls and finally the various fractions of the cell wall components. The following results were obtained: (1) The growth of roots and leaves was hampered in the boron deficient plants. (2) In the boron-deficient leaves a severe necrosis and cracks were developed in the tissue of zone of elongation besides the decrease in growth. (3) under the electorn microscope the cell walls of boron-deficient plants showed rough undulated structures unlike the smooth control cell walls. (4) the dry weight of total cells and cell walls of boron deficient plants were higher than the control plants. (5) In the boron deficient plant the amout of pectin and hemicellulose isolated from cell walls were higher and the amount of protein was lower than the controlled plots.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.1
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• pp.30-42
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• 1986

In order to find out the best media, explants and environmental conditions for induction of calluses and organogeneses of Pinellia ternata (Thunb.) Breit in vitro, various parts of adult have been cultured on Murashige & Skoog's medium containing various levels of 2,4-dichlorophenoxy acetic acid(2,4-D) and kinetin. The results obtained were as follows: Calluses were induced from the surface of apical meristem and leaf tissue. Formation and growth of calluses in petiole ex plants were best on the MS medium complemented with 2,4-D 2.0 mg/l and kinetin 0.2mg/l. But callus formation in stem ex plants of the nearest tuber was not induced at all kinds of media. Plantlets occured at all treatment except absence of growth regulator. Their numbers, size, leaf and fresh weight were promoted by 2,4-D 2.0mg/l and kinetin 0.2mg/l. Root growth was increased on the medium containing higher 2,4-D concentrations. Size and fresh weight of callus were increased at 25$^{\circ}C$ compared with 10, 20 and 30$^{\circ}C$, respectively. Optimal pH value was at 6.0 for growth of callus. Morphological aberrations were observed in plantlets, especially in regenerated leaves. The separation of the broad leaved plantlets and albino were observed in some cultures. Growth of plantlets after transplantation was best in pots with the sterilized vermiculte. But abnormal variants withered up.

• Korean Journal of Plant Resources
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• v.21 no.5
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• pp.362-367
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• 2008

In order to investigate the effect of plant growth regulators on effective in vitro micropropagation, apical meristems of Pulsatilla cernua var. koreana were cultured on Murashige and Skoog's (MS) medium with 2,4-D, NAA, TDZ and BA. Media containing 2,4-D and kinetin, 2,4-D and TDZ, NAA and TDZ were not effective on callus induction. However, embryogenic or organogenic callus was obtained on media containing NAA and BA. Especially, on MS medium with 0.5mg/L NAA and 1.0mg/L BA was optimal for a high frequency (62%) of shoot or shoot bud obtained from callus. Callus proliferation, shoot multiplication and elongation were significantly increased by adding 10% coconut water on MS media with 0.5mg/L NAA and 1.0mg/L BA. Repeated subculturing of in vitro grown shoots resulted in propagation rate of 12.9 shoots per explant every 30 days. Root formation from the adventitious shoots was not easily achieved. However, roots were only produced through callus on MS medium with 2.0mg/L NAA alone or 0.5mg/L NAA and 1.0mg/L BA. These roots were used materials for callus and shoot production repetitively.

• Journal of Plant Biotechnology
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• v.29 no.3
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• pp.189-192
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• 2002

An efficient plant regeneration system of major cultivars of sweetpotato (Ipomoea batatas (L.) Lam.) in Korea via somatic embryogenesis was established. Embryogenic calli were formed from shoot apical meristems of sweetpotato cultivars when cultured on LS medium supplemented with 1 mg/L auxin (2,4-D, picloram, dicamba). Among three kinds of auxin, 1 mg/L 2,4-D showed the highest embryogenic calli induction rate. After 4 weeks of cultures on LS medium supplemented with 1 mg/L 2,4-D, embryogenic calli induction rates of Sinhwangmi, Zami, Yulmi, and White Star were 86%, 78%, 76%, and 80%, respectively. Upon transfer onto LS basal medium, most of somatic embryos developed into plantlets. Regenerated plantlets were transplanted to potting soil and grown to mature plants in a greenhouse.

• Journal of Applied Biological Chemistry
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• v.51 no.3
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• pp.102-110
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• 2008

Complementation assay of the urea uptake-defective yeast mutants led to the identification of the Arabidopsis AtTIP4;1 gene encoding the aquaporin. However, its physiological functions still remain elusive. In the present study, histochemical and genetic analyses were performed to understand the physiological roles of AtTIP4;1 in urea uptake. The AtTIP4;1 product was detectible in the roots, but not in the leaves, the stem, and the flower. Its promoter allowed the expression of the $\beta$-glucuronidase reporter gene in the roots and the apical meristem in Arabidopsis. The AtTIP4;1 products were induced under nitrogen-deficient conditions. To investigate the role of the tonoplast intrinsic protein in urea transport and developments, Arabidopsis with the loss- and the gain-of-function mutations by T-DNA insertion in AtTIP4;1 and 35S promoter-mediated overexpression of AtTIP4;1 were identified, respectively. The transfer DNA insertion and the AtTIP4;1-overexpressed plants showed normal growth and development under normal or abiotic stress growth conditions. The urea-uptake studies using $^{14}C$-labeled urea revealed higher accumulation of urea in the AtTIP4;1-overexpressed plants. These results provide evidence that overexpression of AtTIP4;1 leads to the increase in the urea-uptake rate in plants without detectable defects to the growth and development.

• Journal of Plant Biotechnology
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• v.7 no.2
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• pp.97-103
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• 2005

This study was carried out to obtain basic information for gene manipulation in potent edible tobacco (Nicotiana tabacum cv. TI 516). N. tabacum cv. TI 516 is a plant for a possible candidate to use as an edible vaccine, since it contains a low level of nicotine. The effective plant regeneration system through leaf disc culture was achieved using a MS basal medium supplemented with 0.1 mg $1^{-1}$ NAA and 0.5 mg $1^{-1}$ BA. In order to transform the N. tabacum cv. TI 516 with the green fluorescent protein (GFP) gene, Agrobacterium tumefaciens LBA 4404 containing the GFP gene was used. Genomic PCR confirmed the integration of the GFP gene into nuclear genome of transgenic plants. Expression of the GFP gene was identified in callus, apical meristem and root tissue of transgenic N. tabacum cv. TI 516 plants using fluorescence microscopy. Western blot analysis revealed the expression of GFP protein in the transgenic edible tobacco plants. The amount of GFP protein detected in the transgenic tobacco plants was approximately 0.16% of the total soluble plant protein (TSP), which was determined by ELISA.

• Korean Journal of Weed Science
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• v.17 no.1
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• pp.44-51
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• 1997

Glyphosate had no effect on 5-enolpyruvylshikimate-3-phosphate synthase(EPSP-synthase) biosynthesis per se. But it inhibited clealy the activity of EPSP-synthase. EPSP-synthase seemed to be synthesized as a higher molecular weight(54 kDa) presusor protein and to be transported into plastid. The apparent molecular weight of mature EPSP-synthase in plastid is 45 kDa. Thus, the molecular size of transit peptide appeared to be about 9 kDa. The etiolation for 48 h after glyphosate application did not exhibit the inhibition of translocating level of EPSP-synthase across chloroplast envelope in actively growing meristematic leaves. But even when the plants were etiolated 2 hr after glyphosate treatment, a complete inhibition did not occur at least within 12 hr, i.e. 2 hr after beginning light period, suggesting that EPSP-synthase biosynthesis appeared to be not completely light dependent and the level of EPSP-synthase translocation to chloroplast could be controlled by an unknown regulatory mechanism of light dependent herbicidal effect of glyphosate.

• Korean Journal of Medicinal Crop Science
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• v.6 no.1
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• pp.62-69
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• 1998

There was no significant difference in length and width of leaf and number of leaves per plant between tissue-cultured plants and conventionally propagated ones but chlorophyll content increased in tissue-cultured ones. Percent of sprouting from planted root segments significantly increased in tissue-cultured plants, resulting in yield increase of more than 200% per 10a. Root thickness of tissue-cultured plants at the time of planting influenced percent of sprouting and yield. Plants with root diameter ranging from 3 to 6mm gave good yield. When virus infection was monitored with N. tabacum and C. amaranticolor as indicator plants, 100% infection occurred in vegetatively propagated plants and introduced plants from China. whereas plants obtained from apical meristem showed 0% and 40% to 45% infection in vitro plantlets and 1 year old plants in vivo, respectively. Tobamovirus and unidentified virus particles were detected in electron microscopy.