• Journal of Plant Biotechnology
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• v.44 no.3
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• pp.320-324
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• 2017

Development of modern agricultural machinery and accompanying agricultural development cause soil compaction and reduce growth by stressing roots. Kalanchoe pinnata was used to investigate the impact of stress on rooting and changes in plant growth and reproduction. K. pinnata forms somatic embryos capable of asexual reproduction at the edge of leaves. Impact of root pressurization of K. pinnata on somatic embryogenesis and organ differentiation according to external stress factors was investigated by using a high concentration of agar and this phenomenon was studied histologically. Agar concentration in culture media ranged from 0.5%-1.5% to induce a compression effect on roots. The stem and leaf of K. pinnata were subjected to a microtechnique process to study changes in tissue. In vivo, K. pinnata produced 2nd and 3rd plantlets at edges of leaves from lack of water and excessive lighting conditions. In in vitro culture studies, the lower the concentration of agar, the higher the population and the higher the biomass, but plantlet did not occur in leaf bends. Conversely, as concentration of agar increased, increase in the number of individuals was low. Plantlet development occurred only in agar 1.5% medium. The difference in agar concentration was a stressor in the root of K. pinnata, and thus the pattern of asexual reproduction changed from the division method in root to a plantlet generation in leaf. This suggests root pressurization may act as stress and change in the plant reproduction pattern.

• Journal of Plant Biotechnology
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• v.36 no.2
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• pp.157-162
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• 2009

High frequency plant proliferation system via direct frond regeneration of endemic duckweed plants Lemna paucicostata and Spirodela polyrhiza was established. Fronds of L. paucicostata and S. polyrhiza were able to multiply half-strength MS basal medium without plant growth regulators. However, addition of BA at a range of 1 to 3 mg/L was more effective than high concentration of BA treatments for fronds proliferation. Also half-strength MS salts was suitable for the fronds proliferation. Increase of salts concentration had inhibitory effect on fronds proliferation. Also the frequency of callus formation from fronds of L. paucicostata was 3.3%, when they cultured onto 1/2 MS medium supplemented with 1 mg/L of BA. Similarly the frequency of callus formation from S. polyrhiza was very low. After subculture of white globular structures derived from fronds of L. paucicostata, numerous globular somatic embryos and calluses were developed onto the surface of fronds. However these somatic embryos did not fully develop into normal plants when transferred to 1/2 MS basal medium. Therefore direct frond regeneration system was more efficient for mass proliferation of L. paucicostata and S. polyrhiza. The plant regeneration system of L. paucicostata and S. polyrhiza established in this study, might be applied to mass proliferation and genetic transformation for molecular breeding.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.51-55
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• 2005

Chinese leymus (Leymus chinensis Trin.) is a perennial grass that is widely distributed at high pH sodic and arid soil in the northeastern Asia. An efficient regeneration system was established through somatic embryogenesis of mature seeds to understand its high adaptability to harsh environmental conditions on the basis of molecular biology. The calli were efficiently induced (about $70\%$) from mature seeds on MS medium supplemented with $1.5\;\cal{mg/L}$ 2,4-D. Somatic embryos were formed from the surface of embryogenic callus on MS medium supplemented with $2.0\;\cal{mg/L}\;kinetin\;and\;0.5\;\cal{mg/L}$ NAA after 3 weeks of culture. Roots were induced from the shoot when transferred to MS medium without plant growth regulator for 1 week. Plant regeneration rate was $36\%$ and regenerated plantlets were grown to normal mature plants in pot. An efficient plant regeneration system in this study will be useful for molecular breeding of L. chinensis.

• Journal of Plant Biotechnology
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• v.34 no.1
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• pp.7-10
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• 2007

Plant regeneration system from floral stem of Mymphoides indica via somatic embryogenesis was established. After four weeks of culture onto 1/2MS medium containing 2,4-D, pale-yellow globular structures and calluses were formed on the cut surface of floral stem explants. Upon transfer to 1/2MS basal medium, pale-yellow globular structures were developed into somatic embryos and normal plantlets. These results indicated that pale-yellow globular structures and calluses from floral stem were globular embryos and embryogenic calluses, respectively. The frequency of embryogenic callus formation from floral stem was reached to nearly 100% when floral stem was cultured onto 1/2Ms medium supplemented with low concentration of 2,4-D (0.1 to 0.3 mg/L). However, the higher concentration of 2,4-D resulted in decrease of the frequency of embryogenic callus formation. In this study, low concentration of 2,4-D had a stimulative role in embryogenic callus formation, whereas BA showed inhibitory role in callus formation. In comparison to floral stem, leaf explants showed low frequency of embryogenic callus formation. The highest frequency of embryogenic callus formation from leaf explants was 9.5% when leaf explants were cultured onto 1/2MS medium supplemented with 0.3 mg/L of 2,4-D. The plant regeneration system of Nymphoides indica established in this study, might be applied to mass proliferation, conservation of genetic resources and genetic transformation for molecular breeding.

• Korean Journal of Medicinal Crop Science
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• v.5 no.4
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• pp.289-293
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• 1997

The effects of plant regulators on direct somatic embryogenesis in liquid culture of Rehmannia glutinosa were investigated and the proper explant for direct somatic embryo formation was studied. Direct somatic embryos were induced from leaf segments culture in the MS liquid medium containing 0.5 mg/l of both IAA and NAA, while IBA of 1.0 mg/l was required for the same effect. Many somatic embryos were directly formed at the concentration of 2.0 mg/l cytokinin such as BA, kinetin and zeatin, but somatic embryogenesis was relatively poor at above or below this level. Relatively more somatic embryos were induced in the combination of 1.0mg/l IAA and 2.0mg/l zeatin. Formation of somatic embryos begun after 6 weeks on stem segments, while 7 weeks both on petiole and leaf. However, overall production of somatic embryos after 8 weeks was higher in leaf segment than that of stem segment.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.04a
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• pp.61-62
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• 2003

Clonal propagation of high-value forest trees through somatic embryogenesis (SE) has the potential to rapidly capture the benefits of breeding or genetic engineering programs and to improve raw material uniformity and quality. A major barrier to the commercialization of this technology is the low quality of the resulting embryos. Several factors limit commercialization of SE for Corsican pine, including low initiation rates, low culture survival, culture decline causing low or no embryo production, and inability of somatic embryos to fully mature, resulting in low germination and reduced vigour of somatic seedlings. The objective was to develop a Corsican pine maturation medium that would produce cotyledonary embryos capable of germination. Treatments were arranged in a completely randomized design. Data were analyzed by analysis of variance, and significant differences between treatments determined by multiple range test at P=0.05. Corsican pine (Pinus nigra var. maritima) cultures were initiated on modified !P6 medium. Modifications of the same media were used for culture multiplication and maintenance. Embryogenic cultures were maintained on the same medium semi solidified with 2.5 g/l Gelrite. A maturation medium, capable of promoting the development of Corsican pine somatic embryos that can germinate, is a combination of iP6 modified salts, 2% maltose, 13% polyethylene glycol (PEG), 5 mg!l abscisic acid (ABA), and 2.5 g/l Gelrite. After initiation and once enough tissue developed they were grown in liquid medium. Embryogenic cell suspensions were established by adding 0.951.05 g of 10- to 14-day-old semisolid-grown embryogenic tissue to 9 ml of liquid maintenance media in a 250ml Erlenmeyer flask. Cultures were then incubated in the dark at 2022$^{\circ}$C and rotated at 120 rpm. After 2.53 months on maturation medium, somatic embryos were selected that exhibited normal embryo shape. Ten embryos were placed horizontally on 20 ml of either germination medium ($\frac{2}{1}$strength Murashige and Skoog (1962) salts with 2.5 g/l activated charcoal) or same medium with copper sulphate adjusted to 0.25 mg/1 to compensate for copper adsorption by activated carbon. 2% and 4% maltose was substituted by 7.5% and 13% PEG respectively to improve the yield of the embryos. Substitution of' maltose with PEG was clearly beneficial to embryo development. When 2% of the maltose was replaced with 7.5% PEG, many embryos developed to large bullet-shaped embryos. At latter stages of development most embryos callused and stopped development. A few short, barrel-shaped cotyledonary embryos formed that were covered by callus on the sides and base. When 4% of the maltose was removed and substituted with 13% PEG, the embryos developed further, emerging from the callus and increasing yield slightly. Microscopic examination of the cultures showed differing morphologies, varying from mostly single cells or clumps to well-formed somatic embryos that resembled early zygotic embryos only liquid cultures with organized early-stag. A procedure for converting and acclimating germinants to growth in soil and greenhouse conditions is also tested. Seedling conversion and growth were highly related to the quality of the germinant at the time of planting. Germinants with larger shoots, longer, straighter hypocotyls and longer roots performed best. When mature zygotic embryos germinate the root emerges, before or coincident with the shoot. In contrast, somatic embryos germinate in reverse sequence, with the cotyledons greening first, then shoot emergence and then, much later, if at all, the appearance of the root. Somatic seedlings, produced from the maturation medium, showed 100% survival when planted in a field setting. Somatic seedlings showed normal yearly growth relative to standard seedlings from natural seed.

• Korean Journal of Veterinary Service
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• v.14 no.2
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• pp.87-103
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• 1991

The somatic cell counts SCC and bacteria counts were done by D milk plant, P milk plant, S milk plant and Inch'${\v{\times}}n$ Vet. Serv. Lab from 1987 to 1990 with Coulter counter, Fossomatic 90, Bactoscan, Rolling ball viscometer and Resazurin reduction test. The results were summarized as follows 1. In the distribution of SCC of the bulk herd milk, D milk plant from Nov. 1989 to Oct. 1990 remarks 80.2% on the range below 500, 000, 14.5% ranging from 1, 000, 000 to 1, 500, 000, 1.2% ranging from 1, 500, 000 to 2, 000, 000, 0.69% ranging from 2, 000, 000 to 3, 000, 000, 0.71% on the range over 3, 000, 000. P milk plant remarks 237, 000 in the first half year and 251, 000 in the second half year in 1990 year. S milk plant remarks annual average of 335, 000 in 1987, 273, 000 in 1988 and 262, 000 in 1989. The individual record of Inch'${\v{\times}}n$ Vet. Serv Lab. remarks 79.35% and 80.2% below 500, 000 8.30% and 7.40% from 500, 000 to 1, 000, 000, 2.37% and 3.2% from 1, 000, 000 to 1, 500, 000, 2.77% and 2.30% from 1, 500, 000 to 2, 000, 000, 1.67% and 2.00% from 2, 000, 000 to 3, 000, 000, 5.53% and 4.40% over 3, 000, 000 in 1989 and 1990, respectively. The grade distirbution of SCC is as follows: D milk plant shows 1st grade-80.20%, 2nd grade-l6.5% and 3rd grade-3.30%. And P milk plant shows all 1st grade. S milk plant shows 87.30%, 8.6% and 4.1% in 1987 and 91.90%, 6.1% and 2.0% in 1988, and 92.40%, 6.1% and l.5% in 1989 on the 1st, 2nd and 3rd grade respectively. 2. The distribution of bacteria P milk plant reached 15.123 in 1st half year and 21.515 in 2nd half year. Also, S milk plant reached 81.5%, 12.5%, 6.0% in 1987, and 86.20%, 9.70%, 4.1% in 1988, and 86.2%, 10.8%, 3.0% in 1989 respectively for 1st, 2nd and 3rd grade. 3. The regional SCC distribution in D milk plant shows 1, 540, 000 in three regions and 714, 000 in one region. And monthly SCC distribution shows 671, 000 in December and 1, 165, 000 in June. 4. As a result of the individual SCC test, 9 times for 16 cows in “I”farm(1986-1988), and 6 times for 13 cows in“D”farm(1987-1988) No.3, 5, 9, 14 cows in“I”farm showed the high SCC beyond 1, 000, 000 over 4-5times. 5. If the SCC over 300, 000 reach 40%, the national producing quality of milk can be reduced by 87, 600M /I annually and in the sum of money, it should be about 35.5 billion Won. 6. The difference between high group and low group for SCC in D milk plant reached over 1, 000, 000. In case that the difference reaches 1, 000, 000 in the farm bulk milk at a farm breeding 20 cows which produce 20kg milk per day, it was estimate that the annual difference of producing quantity and sum of money respectively should be reached 26, 280kg in milk and 10, 643, 400 Won in income.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.143-148
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• 1995

The competence of callus formation and plant regeneration from root derived callus was higher in japonica cultivars than those of Tongil-type cultivars of rice. A japonica type cultivars Yeongdeogbyeo, showed the highest capacity (13%) for plant regeneration from root calli of 6 cultivars tested. The callus induced from seed and root tissues maintained higher capacity for plant regeneration during 7 passages of subculture on N$_{6}$ solid media at 2-week intervals. The maximum frequency (2 x 10$^{5}$ mL) of round cells and their cell colonies showed about 24 days after suspension culture of root-derived callus in N$_{6}$ medium with lmg/L 2,4-D, 300mg/L casein hydrolysate, 10mM L-proline, 20g/L sucrose and 30g/L sorbitol. The frequency of somatic embryo formation in suspension cultures of root-derived callus increased with prolonged advance of subculture time from 30 to 90 days, but their regenerative capacities decreased.

• Korean Journal of Veterinary Service
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• v.44 no.3
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• pp.133-140
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• 2021

This study was aimed to investigate the prevalence and antimicrobial resistance of Pseudomonas spp. isolated from bovine mastitis milk samples. A total of 50 (4.9%) Pseudomonas spp. was isolated from 1,023 samples, those collected between 2018 and 2021, derived from 110 dairy farms. The prevalence of the identified species of Pseudomonas isolates was as follows; P. aeruginosa (70.0%), P. fluorescens (14.0%), P. putida (10.0%), P. fragi (4.0%), and P. chlororaphis (2.0%). Most of somatic cell counts in the quarter milk carrying Pseudomonas spp. were less than 3,000,000 cell/ml (90.0%). The isolates of Pseudomonas spp. showed high susceptibility to cefepime (98.0%), ciprofloxacin (98.0%), ceftazidime (96.0%), and colistin (96.0%). The rate of antibiotic resistance in the isolates was highest to ceftiofur (92.0%), followed by the resistance rate to chloramphenicol (86.0%) and trimethoprim/sulphamethoxazole (80.0%). In addition, there is a remarkable difference in antimicrobial resistance pattern among Pseudomonas species. P. aeruginosa and P. putida showed a similar resistance pattern, whereas P. fluorescens showed exceptionally lower resistance to trimethoprim/sulphamethoxazole and chloramphenicol than that of the other species. This study showed that prevalence of Pseudomonas spp. other than P. aeruginosa were 30.0% in bovine mastitis milk, and the occurrence rate of antibiotic resistance were similar or higher level, compared with the previous reports on the mastitisderived Pseudomonas spp. isolated in Korea.

• Plant Biotechnology Reports
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• v.5 no.3
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• pp.197-215
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• 2011

Plant tissue culture and molecular biology techniques are powerful tools of biotechnology that can complement conventional breeding, expedite crop improvement and meet the demand for availability of uniform clones in large numbers. Jatropha curcas Linn., a non-edible, eco-friendly, non-toxic, biodegradable fuel-producing plant has attracted worldwide attention as an alternate sustainable energy source for the future. This review presents a consolidated account of biotechnological interventions made in J. curcas over the decades and focuses on contemporary information and trends of future research.