• The Plant Pathology Journal
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• v.24 no.3
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• pp.283-288
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• 2008

Plant leaf surface is an important niche for diverse epiphytic microbes, including bacteria and fungi. Plant leaf surface plays a critical frontline defense against pathogen infections. The objective of our study was to evaluate the effectiveness of a starch-based super-absorbent polymer(SAP) combination, which enhances water potential and nutrient availability to plant leaves. We evaluated the effect of SAP on the maintenance of bacterial populations. In order to monitor bacterial populations in situ, a SAP mixture containing Pseudomonas syringae pv. tabaci that expressed recombinant green fluorescent protein(GFPuv) was spray-challenged onto whole leaves of Nicotiana benthamiana. The SAP combination treatment enhanced bacterial robustness, as indicated by disease severity and incidence. Unexpectedly, bacterial numbers were not significantly different between leaves treated with the SAP combination and those treated with water alone. Furthermore, young leaves treated with the SAP combination had more severe symptoms and a greater number of bacterial spots caused by primary and secondary infections compared to young leaves treated with the water control. In contrast, bacterial cell numbers did not statistically differ between the two groups, which indicated that measurement of viable GFP-based bacterial spots may provide a more sensitive methodology for assessing virulence of bacterial pathogens than methods that require dilution plating following maceration of bacterial-inoculated leaf tissue. Our study suggests that the SAP combination successfully increased bacterial aggressiveness, which could either be used to promote the ability of biological agents to control weedy plants or increase the robustness of saprophytic epiphytes against competition from potentially harmful microbes.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.129-134
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• 2001

Winter bud explants from 15 individual angelica tree (Aralia elata) were cultured in vitro to find out optimal conditions for somatic embryo induction as well as plant regeneration. Calli are induced and grown on MS medium supplemented with 1.0 mg/L 2,4-D for 4 weeks and subcultured on a half-strength MS medium without phytohormones to induce somatic embryos. Inter-simple sequence repeat (I-SSR) markers were analyzed with total DNAs extracted from the trees. Genotype effects on somatic embryo induction were examined by cluster analysis. Callus induction rate varied from 58.5 to 100% among the genotypes. Somatic embryo induction rate also greatly varied from 0 to 100% among the genotypes. There was a significant difference in somatic embryo induction rate even among the individual trees that showed close genetic relationships each other. This suggested that somatic embryo induction rate in Aralia elata be influenced by a few major specific genes rather than whole genomic similarity among individual trees. Four individuals of Ulneong-7, Cheju-1, Shingu and China, which are recalcitrant to somatic embryo induction, turned out to have a close genetic relationship, suggesting that both physiological and genetic factors affect somatic embryo induction. The results suggest that genotype selection be the most important factor to achieve an efficient propagation, although cultural optimization through medium and explant manipulation may also play crucial roles in somatic embryogensis as well as plant regeneration of these species.

• Korean Journal of Plant Tissue Culture
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• v.21 no.1
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• pp.55-58
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• 1994

Agrobacterium tumefaciens LABA4404 harboring plant binary vector, pBI121, was used for genetic transformation of lettuce (Lactuca sativa t.). Cotyledon segments were infected with A. tumefaciens LBA4404 by cocultivation method and regenerated. Regenerated letture was subject to molecular analyses for integration into plant nuclear genome and expression of ${\beta}$-glucumnidase (GUS) gene. Southern and Northern blot analyses demonstrated that GUS gene was integrated into plant nuclear genome and expressed into its mRNA. The expression of GUS gene into its protein was confirmed by specetrophotometric assay of GUS activity.

• Plant Biotechnology Reports
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• v.2 no.2
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• pp.153-161
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• 2008

The factors influencing somatic embryo maturation, high frequency somatic embryo germination, and plantlet formation were studied in Terminalia chebula Retz. Maturation of somatic embryo were influenced by a number of factors such as in vitro culture passage, concentrations of sucrose, levels of abscisic acid (ABA), basal media and media additive combinations. Maximum frequency of somatic embryo maturation ($57.22{\pm}2.02$), was obtained on MS medium supplemented with 50 g/l sucrose. Different factors such as strengths of MS nutrients, plant growth regulators, media additives and their combinations controlling somatic embryo germination and plantlet formation were studied. High frequency of germination and plantlet formation ($58.80{\pm}1.47$) were achieved by subsequent subculture of mature somatic embryos on MS medium containing 30 g/l sucrose and 0.5 mg/l benzyl-adenine (BA). However, although duration of in vitro passage of the callus tissue was critical, contribution of the combinations of plant growth regulators and media additives showed nugatory effect on somatic embryo maturation and germination as evident from variable responses.

• The Plant Pathology Journal
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• v.17 no.3
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• pp.128-140
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• 2001

Infection of pepper leaves by Colletotrichum cocodes at the two- and eight-leaf stages caused susceptible and resistant lesions 96 h after inoculation, respectively. At the two-leaf stage, progressive symptom development occurred on the infected leaves. In contrast, localized necrotic spots were characteristic symptoms at the eight-leaf stage. Infected leaves at the two-leaf stage exhibited cell death accompanied by the accumulation of autofluorescent compounds. At the eight-leaf stage, pepper leaves infected by the anthracnose fungus displayed localized autofluorescence from the symptoms. Infection of pepper leaves by C. cocodes at the two-leaf stage resulted in its rapidand massive colonization of all the leaf tissues including the vascular tissue, together with cytoplasmic collapse, distortion of chloroplasts, and disruption of host cell walls. However, penetration of C. cocodes was very limited in the older leaf tissues of pepper plants at the eight-leaf stage. Fungal hyphae grew only in the intramural spaces of the epidermal cell walls at this stage. Occlusion of amorphous material in xylem vessels, aggregation of fibrillar material in inter-cellular spaces, and deposition of protein bodies were found as resistance responses to C. cocodes.

• Korean Journal of Plant Tissue Culture
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• v.25 no.5
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• pp.319-322
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• 1998

Culture conditions for high frequency embryogenesis and plant regeneration in anther cultures of various F$_1$ hybrid and homozygous lines of pepper (Capsicum annuum L.) are described. Anthers pigmented less than halfway from the distal end were dissected from the flower bud in which petals elongated 2 mm higher than the receptacle. They were placed on Dumas medium supplemented with 0.1 mg/L 2,4-D and 0.1 mg/L kinetin. After four weeks of culture, embryos began to appear on anthers. After eight weeks of culture, frequencies of embryo formation reached up to 58.3%. Upon transfer to MS basal medium, greater than 95% of embryos developed into plantlets.

• Plant Biotechnology Reports
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• v.3 no.4
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• pp.341-345
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• 2009

This study describes culture conditions for a plant regeneration system via a combined pathway of somatic embryogenesis and organogenesis in root explant cultures of the commercial rose cultivar 'Charming'. Root explants formed white calluses at a frequency of 30% after 6 weeks of culture on Schenk and Hildebrandt (SH) medium supplemented with $11mg\;1^{-1}$ 2,4-dichlorophenoxyacetic acid. After 6 weeks of transfer to SH medium without growth regulators, initial white calluses gave rise to globular somatic embryos at a frequency of 2.8%, which were subsequently dedifferentiated to embryonic tissues. Somatic embryos or embryonic tissues initially derived from root explants did not undergo development beyond cotyledonary stage. To produce adventitious shoots, embryonic tissues were sliced and cultured on SH medium with $0.5mg\;1^{-1}$ 6-benzyladenine. After 4 weeks of culture, 28% of embryonic tissue explants formed adventitious shoots. Regenerated shoots were rooted on half strength SH medium with $0.1mg\;1^{-1}$ ${\alpha}-naphthalaneacetic$ acid and subsequently grown to maturity. Root-derived embryonic tissues were proliferated by subculture, while retaining the capacity for shoot production for a few years.

• 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.

• Plant Resources
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• v.6 no.3
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• pp.205-210
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• 2003

Ginseng(Panax ginseng C.A. Meyer) is a perennial herbaceous plant which grows very slowly. It takes about 3 to 4 years from seeding to collecting the ripe seeds and the ginseng propagation is very difficult. and so, it is very difficult to breed ginseng plant. Ginseng tissue culture was started from at 1960, and ginseng commercial product by in vitro callus culture was saled, however upto now, regenerants were not planted to soil normally. Recently, plant genetic engineering to produce transgenic plants by introducing useful genes has been advanced greatly. In a present paper, transformation of ginseng plants was achieved by co-cultivation with Agrobacterium harboring the binary vector coding Proteinase-II gene, which confer resistant or tolerant to insect pests, The binary vector for transformation was constructed with disarmed Ti-plasmid and with double 35S promoter. The NPT II gene and introduced genes of the transgenic ginseng plants were successfully identified by the PCR. Especially the transgenic ginseng plants were regenerated using new techniques such as repetitive single somatic embryogenesis.

• Korean Journal of Plant Resources
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• v.17 no.1
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• pp.1-6
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• 2004

Apical meristems tissue were cultured on LS medium with different zeatin and NAA concentrations to compare their potential to regenerate shoots, roots and bulblet formation. Shoot regeneration from apical meristem was effective on LS medium added with zeatin 0.1, 0.5, 1.0 mg/L alone treatment or zeatin 0.5 mg/L and NAA 1.0 mg/L combination treatment. A high frequency of root regeneration was obtained on LS medium supplemented with zeatin 0.5 mg/ and NAA 1.0 combination treatment. Linsmaier and Skoog(LS) medium with NAA 3.0 mg/L and zeatin 1.0 mg/L combination treatment gave the best results for normal bulblet formation#KW=Allium wakegi ; plant regeneration ; bulblet formation