• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.131-135
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• 1995

Physiologically modified stem nodes derived from ex vitro and in vivo explants of hybrid aspen (Populus alba L.X P.grandidentata Michx. 'Crandon') were tested for their multiple shoot regeneration capacity using a broad spectrum dosage of cytokinins. Ex vitro derived stem nodes with excised axillary buds at the time of culture produced 11 to 13 multiple shoots on 20 to 30 $\mu$M zeatin containing Woody Plant Medium (WPM) after 6 weeks. Excision of axillary bud sprouts after 2 weeks of culture and culture of the remaining stem nodes on WPM with 1.0 to 2.0 $\mu$M BA or 10 to 30 $\mu$M zeatin produced 13 to 15 and 7 to 8 shoots per explant, respectively, Multiple tiny shoots were produced when in vivo derived stem nodes (on which all leaves were removed) were cultured on WPM with 30 to 50 $\mu$M 2iP or 20 to 50 $\mu$M zeatin. The greatest number of multiple tiny shoot proliferation (32 to 50 shoots per explant) were obtained when the explants were cultured on media containing 20 $\mu$M zeatin. Successful transplanting of these multiple shoots into the greenhouse and/or nursery was achieved.

• Journal of Korean Society of Forest Science
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• v.26 no.1
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• pp.19-22
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• 1975

Freezing resistance of ten cultivars of Chestnut (Castanea crenata S. et Z.) collected from four different sites of Kyunggi Province, Korea on March 2, 1975, was measured to find out the differences among tissue parts, and those among cultivars. The freezing and thawing rates were controlled lower than $6^{\circ}C/hr$. which occurs in nature. The resistance to low temperature was in order from lowest to highest; winter bud, cambium, xylum ray parenchyma and bark cortex. The difference in cold hardiness among cultivars was not consistent among tissue parts of twig stem except in cultivar Dan-Taeck of which all tissue parts showed highest cold-hardiness. The importance of the study on the seasonal variation in cold hardiness of different tissue parts was discussed in terms of choosing the most cold resistant Chestnut culitivar in Korea.

• Korean Journal of Plant Resources
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• v.28 no.6
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• pp.697-703
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• 2015

Twenty apple germplasm accessions from the Korean Genebank were successfully cryopreserved using two-step freezing to back up genetic resources maintained by field collections. This study examined the morphological and genetic stability of cryopreserved dormant apple buds that were stored in liquid nitrogen, and then rewarmed and regrown. Whole plants were regenerated directly from dormant buds through budding without an intermediary callus phase. The cryopreserved buds produced high levels of shoot formation (76.2-100%), similar to those of noncryopreserved buds (91.3-100%), with no observed differences between cryopreserved and noncryopreserved materials. Three of the twenty cryopreserved apple germplasm accessions were used to assess morphological and genetic stability. No differences in morphological characteristics including shoot length, leaf shape, leaf width/length ratio, and root length were observed between controls (fresh control and noncryopreserved) and cryopreserved plantlets. The genetic stability of regenerants (before and after cryopreservation) was investigated using inter simple sequence repeat (ISSR) markers. The ISSR markers produced 253 bands using four primers, ISSR 810, SSR 835, ISSR 864, and ISSR 899. These markers showed monomorphic banding patterns and revealed no polymorphism between the mother plant and regenerants before and after cryopreservation, suggesting that cryopreservation using two-step freezing does not affect the genetic stability of apple germplasm. These results show that two-step freezing cryopreservation is a practical method for long-term storage of apple germplasms.

• The Korean Journal of Ecology
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• v.15 no.1
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• pp.19-33
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• 1992

The density, litterfall, phytomass, and primary productivity for 7 years in quercus mongolian forest locasted at mt. nambyengsan, pyeongchang-gun, gangwon provance in central part of korean peninsula were estimated quantitatively. at the first year in 1984, a stand had 1, 450 trees/ha in tree density, which was 0.67 of skewness and 0.54 of kurtosis in frequency distribution, however, at the 7th year in 1990, the stand had 1, 133 trees/ha in the density with 22%(or 316 tree/ha)in mortality, which was 1.16 of skewness and 1.89 of kurtosis in the frequency. annual mean litterfall was 5 ton DM/ha, which was composed of 68% of leaves, 17% of branches, 3% of bud scales, 9% of arcons and cups, 0.7% of flowers and others. the phytomass of tree layer for 7 years was gradually increased from 149.7 ton DM/ha at the first year to 188.5 ton DM/ha at the 7th year.annual net productivity for the tree layer studied ranged from 8.76 ton DM/ha.yr-1 to 11.62 ton DM/ha. yr-1 with heavy fluctuation year by year. average annual productivity of the stand of trunk, branches, leaves and roots for 7 years were 4.42, 0.67, 3.85 and 1.29 ton DM/ha.yr-1, respectively. turnover rate of the stand was 6.9% at the first year and 5.6% at the 7th year. such fluctuation of the productivity was caused by the chang of density, mortality, mortality and turnover rate.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.39-44
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• 2010

An efficient method for the rapid propagation of Smilax china from axillary buds was established. Plants with thick leafage were selected from Korea native S. china population. Axillary buds of S. china collected from selected plant and were cultured in various culture media (2MS, MS, 1/2MS, WPM, B5 and SH medium). Shoot was induced from axillary bud on MS basal medium after 4 weeks of culture. 1/2MS medium showed a higher growth rate than those of the others, while the lowest shoot growth was obtained in 2MS medium. Among the sucrose concentrations, 5% sucrose was the optimum level for shoots growth from axillay buds. Among cytokinins, $0.5mgL^{-1}$ 6-benzylaminopurine (BAP) treatment showed the best performance on shoot multiplication, yielding average shoot multiplication forming about 2.4. Rooting was induced directly near the base of the shoot on 1/2MS medium containing with three-auxins ${\alpha}-napthalene$ acetic acid (NAA), indole acetic acid (IAA) and ${\beta}-indolebutyric$ acid (IBA) (0.5 and $1.0mgL^{-1}$). The $1.0mgL^{-1}$ IBA treatments induced earliest rooting with maximum of root number and root growth. These rooted plantlets were successfully transferred to pots for 4 weeks hardening process, and were transferred to soil with above 90% survival rate.

• Journal of People, Plants, and Environment
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• v.22 no.6
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• pp.583-591
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• 2019

This study was conducted to examine the effects of wet storage solution, transport period and temperature on vase life and quality of cut flowers in standard chrysanthemum 'Jinba'. Immediately after transport, the fresh weight and flower diameter of cut flowers did not show a difference according to wet storage solutions regardless of the transport period, but as the transport period increased, the fresh weight and flower diameter increased. The flower bud stage at harvest was maintained due to the small changes in flower diameter, and the freshness of leaves was better when transported at 5℃ than at 25℃. When transported at 25℃, the longer the transport period, the lower the quality of cut flowers as some petals opened up and showed early flowering after transport. In preservative solutions, quality of cut flowers transported at 25℃ was lower than that at 5℃ due to fresh weight and diameter according to the longer transport period. The vase life of cut flowers was 1.0 day, 0.8 day, and 7.3 days longer when transported for 3, 5, and 7 days respectively at 5℃ than at 25℃. The quality of cut flowers was better due to increase in fresh weight and flower diameter, as well as vase life in wet storage solutions of ClO₂ and Chrysal OVB than in tap water, regardless of transport period and temperature. There was no difference in fresh weight and vase life between ClO₂ and Chrysal OVB, but flower diameter was greater in ClO₂ than in Chrysal OVB. Therefore, for long-term transport of cut standard chrysanthemum 'Jinba', wet storage transport in ClO₂ at 5℃ was found effective in maintaining the quality and vase life of cut flowers.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.23-23
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• 2021

Apple (Malus×domestica Borkh.; Rosaceae) is an important fruit crop grown mainly in temperate regions of the world. Tissue culture in vitro is a biotechnological technique that has been used to genetically improve cultivars (scions) and rootstocks. This could be important in the production of genetically uniform scions and rootstocks for commercial apple production. In nurseries, apple plants are produced by grafting scions onto rootstocks. The Cornell-Geneva (Geneva® series) breeding program has bred several dwarf rootstocks that are resistant to diseases and pests and are also cold hardy. This study was conducted to determine the optimal medium strength to improve sprouting shoot rate of apical meristem of the apple rootstocks of fire blight resistance. The apple rootstocks apical meristem at size (0.2 mm to 0.3 mm) with axillary buds were cultured on the MS(Murashige & Skoog) medium supplemented with plant growth regulators. The sprouting ratio and growth characteristics was evaluated after eight weeks in vitro culture. The highest rate of bud differentiation and shoot formation were 23.8% and 55.6%, respectively. After 6 weeks, shoots were regenerated from apical meristem, and their growth characteristics was significantly varied on the respective basal medium with different plant growth regulators. Our studies showed that the apple rootstocks the apple rootstocks of fire blight resistance plantlets could be successfully produced from apical meristem differentiated out of young twigs via organogenic regeneration.

• Tuberculosis and Respiratory Diseases
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• v.54 no.1
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• pp.45-56
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• 2003

Background : Mycobacterium abscessus is the most common respiratory pathogen in rapidly growing mycobacteria and is resistant to all of the first-line antituberculosis drugs. This report describes the clinical and radiographic characteristics in patients with pulmonary disease caused by M. abscessus. Materials and Methods : Twelve patients with pulmonary disease caused by M. abscessus who fulfilled the 1997 American Thoracic Society diagnostic criteria for a nontuberculous mycobacterial pulmonary infection were observed over a five-and-a-half year period. The clinical characteristics and chest radiographic findings were analyzed, retrospectively. Results : The patients were predominantly female(11/12, 92%) and nonsmokers(12/12, 100%). Coughing (10/12, 83%), sputum(10/12, 83%) and hemoptysis(10/12, 83%) were the common symptoms and they had prolonged periods from the onset of symptoms to the diagnosis of their disease(median 6.5 years). Eleven (92%) patients had a previous history of being treated for pulmonary tuberculosis. The sputum specimens were acid-fast bacilli smear-positive in all patients. All patients were administered antituberculosis drugs. Six (50%) patients were treated with second-line antituberculosis drugs on account of persistent smear-positive sputum specimens. The chest radiographs showed that reticulonodular opacities(11/12, 92%) were the most common pattern of abnormality, followed by cavitary lesions(5/12, 42%). The computed tomography findings suggested bronchiolitis from the centrilobular nodules with a tree-in-bud appearances(9/10, 90%) and bronchiectasis (9/10, 90%) were the most common, followed by well-defined nodules smaller than 10-mm in diameter(7/10, 70%). Conclusions : M. abscessus pulmonary disease should be recognized as a cause of chronic mycobacterial lung disease, and respiratory isolates should be assessed carefully.

• Horticultural Science & Technology
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• v.18 no.1
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• pp.28-32
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• 2000

This study was carried out to investigate the effects of uniconazole treatment on the growth and flowering of potted Chrysanthemum indicum L. for high quality pot plant production. Uniconazole was drenched at 0.05, 0.01, or 0.15 mg a.i./pot at 14 days after planting (DAP) of rooted cuttings. Simultaneously the short-day treatment (SDT) and pinching were adapted. The same amount of uniconazole (0.05 mg a.i./pot) was spilt drenched at once, twice, and three times, respectively, at 1 week interval. Uniconazole markedly reduced plant height, branch length, and stem diameter. Plant height was reduced linearly with increasing uniconazole concentration at 0.05, 0.01, or 0.15 mg a.i./pot up-to 41.6%, 52.5%, and 58.5%, respectively. In 0.05 mg a.i./pot, the number of branches greatly increased and plant height of 22.6 cm was adequate for pot plant. However, higher concentrations (0.10, 0.15 mg a.i.) were not suitable for production of high quality pot plant (17.0, 14.8 cm, respectively). Pinching and SDT decreased the number of days to visible bud, while uniconazole treatments delayed days to visible bud by 5-9 days compared with pinching and SDT. Number of visible buds was highest at 0.05 mg a.i./pot uniconazole treatment. However, flower diameter was decreased by uniconazole treatment, resulting in compact form. Number of stomata was increased by uniconazole treatment. The length of vascular tissues of uniconazole-treated plants ($11.2{\mu}m$) was smaller than that of non-treated plants ($15.0{\mu}m$, and the size of xylem vessel was also decreased. Uniconazole treatment at 0.05 mg a.i./pot at 14 DAP with pinching and SDT were recommended for pot plant production of C. indicum L.

• Horticultural Science & Technology
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• v.18 no.3
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• pp.378-382
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• 2000

For the production of second crop in 'Campbell Early' grape, the primary shoots were pruned at 3rd, 6th or 9th nodes from the shoot bases on 13 days, 23 days and 33 days after full bloom date on 7th June. Secondary shoots were sprouted 7~8 days after the pruning, and it took 19~25 days for the flowering on the secondary shoots. The flower cluster number on secondary shoots were 2.8 for 13 days after full bloom, and 3.2 for 23 days and 33 days after full bloom, meaning little effect by pruning time. The 3rd node pruning produced 2~2.4 flower clusters with flower cluster length of 9.3~10.4 cm, while the 6th or 9th node pruning produced 3.1~3.8 flower clusters with flower cluster length of 12~14.9 cm, showing superior flower cluster length for the 6th or 9th node pruning. The secondary shoots developed from the buds pruned 13 days after full bloom with pruning bud positions of 6th nodes demonstrated superior fruits with higher soluble solids and lower acidity than the rest of the pruning times and positions.