• Journal of Plant Biotechnology
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• v.30 no.2
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• pp.155-160
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• 2003

Grapevine leafroll-associated virus 3(GLRaV-3) is one of the most severe pathogens for viral diseases found in Korea. This study was conducted to establish the virus-free stock production system for the virus disease control. The effects of thermotherapy, merestem culture and chemotheratpy to eliminate the GLRaV-3 in gratevines were tested. Thermotherapy at 37$\pm$2$^{\circ}C$ for 6∼8 weeks combined with 0.5∼1.0mm size of meristem culture method was the most effective for virus elimination. Thermotherapy alone was not effective. In chemotheratpy, DHT and Amantadine (20, 40mg/L) treatment in medium was more effective than Ribavirin to eliminate the GLRaV-3 in grapevine. However, Ribavirin spraying to potted was not available for virus elimination. Therefore, virus-free stock production system using the thermotherapy combined with shoot apical meristem culture was the most effective in grapevine.

• The Plant Pathology Journal
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• v.15 no.2
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• pp.127-130
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• 1999

Cytological changes of cowpea root at the early stage of root nodule formation (within 5 days after inoculation) were viewed by light and electron microscopy. The root region affected by the rhizobial infection, which was composed of a redial array of cortical cells, had prominent cell divisions, mostly anticlinal in the inner cortical cells and in addition oblique and periclinal in the outer cells. An infected root hair cell (or root hair-producing epidermal cell) had numerous infection threads and degenerated cytoplasm. Module meristem was formed adjacent to the infected root hair cell, and characterized by dense cytoplasm, prominent nucleus, numerous small vacuoles, and increased plastids, containing infection threads as well. Bacterial cells were dividing inside the infection thread, the wall materials of which appeared to be dissolved ad accumulated in small vacuoles. inner cortical cells contiguous to the nodule meristem appeared to be actively dividing and dedifferentiating; however, they were not infected by the rhizobia. These structural characteristics are similar to those in the Bradyrhizobium-soybean association previously reported, and may reflect the similar cytological process in cowpea in the early nodule formation.

• Molecules and Cells
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• v.21 no.1
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• pp.141-146
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• 2006

We previously showed that NtCDPK1, a tobacco calcium-dependent protein kinase, interacts with and phosphorylates the Rpn3 regulatory subunit of the 26S proteasome, and that both NtCDPK1 and Rpn3 are mainly expressed in rapidly proliferating tissues, including shoot and root meristem. In this study, we examined NtCDPK1 expression in roots using GUS expression in transgenic Arabidopsis plants, and investigated its function in root development by generating transgenic tobacco plants carrying a sense NtCDPK1 transgene. GUS activity was first detected in roots two days after sowing. In later stages, strong GUS expression was detected in the root meristem and elongation zone, as well as the initiation sites and branch points of lateral roots. Transgenic tobacco plants in which NtCDPK1 expression was suppressed were smaller, and their root development was abnormal, with reduced lateral root formation and less elongation. These results suggest that NtCDPK1 plays a role in a signaling pathway regulating root development in tobacco.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.54-54
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• 2019

Apple (Malus domestica) is one of the most economically important fruits in Korea. But virus infection has decreased sustainable production of apple and caused the serious problems such as yield loss and poor fruit quality. Virus or viroid infection including Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple mosaic virus (ApMV) and Apple scar skin viroid (ASSVd) has been also reported in Korea. In many cases, apple is infected with virus and viroid with no specific symptoms, the damage caused by the virus are unaware significantly. In our research, we tried to eliminate viruses in the rootstock for the disease-free seedlings of the apple dwarfing rootstock M.9 and M.26. The method of virus elimination was meristem culture, heat($37^{\circ}C$, 6weeks) treatment and chemistry($Ribavirin^{(R)}$) treatment. The analytical methods commonly used for the detection of virus is Enzyme-linked Immuno-Sorbent Assay(ELlSA) and Reverse Transcription-polymerase Chain Reaction(RT-PCR). RT-PCR method was more 30% sensitive than ELISA method. Efficiency of method eliminate virus appeared meristem method > heat treatment > chemistry treatment. The higher acquisition rate of disease-free seedlings is 30~40% on meristem treatment. In meristem treatment, the apple dwarfing rootstock M.9 gained infection ratio of ACLSV, ASPV and ASGV were 45%, 60% and 50% respectively. In the apple dwarfing rootstock M.26, infection ratio of ACLSV, ASPV and ASGV were 40%, 55%, 55%, respectively. Based on our results, it was found that most effective method of disease-free seedlings apple dwarfing rootstocks was by meristem treatment than heat method and chemistry treatment.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.228-235
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• 2019

Apple (Malus pumila) is one of the most economically important fruits in Korea. but virus infection has decreased the sustainable production of apples and caused serious problems such as yield loss and poor fruit quality. Virus or viroid infection including apple chlorotic leaf spot virus (ACLSV), apple stem pitting virus (ASPV), apple stem grooving virus (ASGV), apple mosaic virus (ApMV) and apple scar skin viroid (ASSVd) have been also reported in Korea. In many cases, as apple gets infected with virus and viroid with no specific symptoms, the damage and symptoms caused by the viruses are not detected. In our research, viruses in the rootstock were eliminated for a virus-free apple dwarfing rootstock of M.9 and M.26. The virus elimination methods were apical meristem culture, thermotherapy ($37^{\circ}C$, 6 weeks) and chemotherapy($Ribavirin^{(R)}$). The detection of apple viruses was accomplished by Enzyme-linked Immuno-Sorbent Assay (ELlSA) and reverse transcription-polymerase chain reaction (RT-PCR). RT- PCR method was 10 ~ 30% more sensitive than the ELISA method. The efficiency of virus elimination was enhanced in apical meristem culture method. The acquisition rate of virus-free apple dwarfing rootstocks was 30 ~ 40% higher in apical meristem culture. After the meristem culturing of M.9, the infection ratio of ACLSV, ASPV and ASGV was 45%, 60% and 50%, respectively. In the apple dwarfing rootstock of M.26, the infection ratio of ACLSV, ASPV and ASGV was 40%, 55% and 55%, respectively. Based on this study, the best method for the production of virus-free apple dwarfing rootstocks was the apical meristem culture.

• Korean Journal of Pharmacognosy
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• v.3 no.2
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• pp.65-72
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• 1972

Tissues of $Panax\;Schinseng\;N_{EES}\;root$ were cultured on the synthetic agar media to investigate the nutrient efficiency on the callus induction and organ formation. The differentiation pattern of the callus mass and the structure of the induced organ (root) were observed internally. On White's medium, callus formation needed the supplement of 2,4-D (5mg/l) and kinetin (1.0mg/l), and on MS medium the root induction NAA (0.2mg/l) and kinetin (0.1mg/l). In order to investigate the effect of inorganic components on callus formation, the inorganic part of White' medium was substituted with those of Heller, Murashige Skoog, and Earle. As the result culture Earle's was most effective. On the other hand, the roots were induced from the meristem in the deep region of callus mass. Since this meristem is similar to the pericambium of tap root, they are the same on the pattern of morphogenesis.

• Journal of Plant Biology
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• v.38 no.1
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• pp.33-38
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• 1995

Hydroxyurea (HU), a DNA synthesis inhibitor, was tested as synchronizing agent in root-tip meristem of Allium wakegi. Roots were treated with 2.5mM HU for 14 h to accumulate meristem root-tip cells at the G1/S interface. After release from HU block, the cells re-entered the cell cycle with a high degree of synchrony. Synchronized mitotic frequency of A. wakegi was 22.7%, which was about 3.9 times as high as that of the control. The highest metaphase index(23.0%) was obtained when, 6 h after release from the HU block, the roots were treated with 0.05% colchicine for 2 h. Modifying various Giemsa staining protocols defined for animals and a few plant species, G-bands were visualized at prometaphase and metaphase chromosomes of A. wakegi. The higher degree of chromosome condensation, the less differential bands could be resolved. This is the first demonstration introduced partial mitotic synchronization into G-banding in plant.

• Journal of Forest and Environmental Science
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• v.27 no.2
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• pp.61-72
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• 2011

Micropropagation is an alternative mean of propagation that can be employed in mass multiplication of plants in relatively shorter time. Recent modern techniques of propagation have been developed which could facilitate large scale production of true-to-type plants and for the improvement of the species using genetic engineering techniques in the next century. An overview on the in vitro propagation via meristem culture, regeneration via organogenesis and somatic embryogenesis is presented. The usefulness of the plants in commercial industry as well as propagation techniques, screening for various useful characteristics and the influence of different cultural conditions in the multiplication, rooting and acclimatization phases on the growth of tissue cultured plant discussed.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2002.04a
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• pp.51-51
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• 2002

• Proceedings of the Zoological Society Korea Conference
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• 1999.10b
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• pp.90.1-90
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• 1999

No Abstract, See Full Text