• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.161-168
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• 2004

Optimal regeneration conditions of ginseng transformants were studied. It has been known that Ferritin Light Heavy Chain (FLHC) gene remove the several heavy metal by combination, store and transport. To obtain the ginseng tolerant to heavy metal, binary vector was introduced in Agrobacterium by tri-parental mating and then Agrobacterium tumefaciens MP90/FLHC was selected on the AB media and MS media containing kanamycin. Explants were co-cultured with Agrobacterium tumefaciens MP90/FLHC, which contained NPT II as a selectable marker, tadpole ferritin heavy chain (FLHC) gene and human ferritin light chain gene and then a number of embryos were induced. The induced embryo transferred to shooting media consisting of MS medium supplemented with GA 10 mg/L. As a result of examination that induced the normal growth of transfomants, transformants showed the equivalent growth in both root and shoot on the media containing the 1/3 MS.

• Korean Journal of Plant Tissue Culture
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• v.22 no.2
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• pp.115-120
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• 1995

A method for cryopreservation of suspension cultured embryogenic cells derived from immature zygotic embryos of rice (Korean cultivars, Donggin-byeo and Taebaeg-byeo) was developed. The highest cell regrowth after storage in liquid nitrogen was obtained when Donggin-byeo cells were cryoprotected with a mixture of 2 M DMSO and 0.4 M sucrose and Taebaeg-byeo cells with a mixture of 0.64 M DMSO and 0.4 M sucrose at frequencies of 88% and 90%, respectively, Pretreatment in a high osmotic medium was not necessary. Upon transfer to $N_{6}$ medium suplemented with lmg/L NAA and 5 mg/L kinetin, the regenerated calli gave rise to numerous somatic embryos which subsequently underwent development into plantlets. Among approximately 100 plantlets, 25% of them were albinos.s.

• Journal of Korean Society of Forest Science
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• v.82 no.3
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• pp.254-259
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• 1993

For the production of mycoplasma-free jujube trees from mycoplasma-infected trees in vitro micrografting visas carried out using apical meristems of in vitro grown plantlets as scions. The rootstocks were hypocotyl segments of in vitro germinated seedlings of Zizyphus jujuba Mill. which is widely used as rootstocks in the field grafting. Ten percent of scions showed normal growth and grew into plants. The presence of mycoplasma was tested using transmission electron microscopy and fluorescence microscopy. Mycoplasma was not found in the tissues of scion parts and seedlings, whereas it was found in in vitro grown plantlets. This suggests that the production of mycoplasmaa-free jujube trees is possible by the in vitro micrografting technique.

• Journal of Plant Biotechnology
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• v.36 no.4
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• pp.392-396
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• 2009

Protocorms were newly formed from the culture of axillary buds, obtained in the seedlings of Dendrobium moniliforme in vitro. Its formation ratio was calculated to 43.7% on MS medium containing 1.0 mg/L BA. To test their survival ratio, we gradually increased the inoculation of transplant populations from single to more than three, and then found that the ratio in three populations went up as high as 95.2% rather than those of one or two. In bioreactor, explant obtained from the axillary bud grew well in lower concentration as 1/4 MS medium, while clearly grew slow in a little bit high concentration as 1/2 MS medium. We found that the explant of axillary bud, obtained from the Dendrobium moniliforme seedlings, would grow five times after culturing in a bioreactor for six weeks in 1/4 MS medium.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.30-39
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• 1998

Carrot seedling emgryos showing variations in cotyledon number were selected and anatomical comparisons of the embryo vascular systems were performed between the variants and normal two cotyledonary (5) embryos from 800 seedings germinated . Externally, all of the four and six cotyledonary embryos had two cotyledonary petioles. Each of the cotyledonary petioles divided into two or three on the upper part fo the petiole which result in four and six cotyledons, respectively. However, the embryos had three different cotyledonary petioles in the three cotyledonary embryos. On the basis of the pattern of vascular system, the four and six cotyledonary embryos had the same basic vascular system as fnormal two cotyledonary embryos, Therefore the cotyledon number abnormality could result from the branching split of the abnormally thickened upper part of the cotyledonary petiole. However, the three cotyledonaryembryos had a different vascular system from the normla two cotyledonary embryos. They could be regarded as different varieties form the two cotyledon embryos. All embryos observed had short cylindrical plumule sheath which formed by the fusion of the cotyledon bases. The presence of plumule sheath strontgly implied that the initiation of the cotyledons was not from the two localized primordia but from the circular proimordiu formed at the blobular stageof embryo, and it is not consistent with current views of cotyledon initiation. On the formation of the primary vascular system of carrot seedlings, it is suggested that the primary vascular system of the plumule was formed independently from that of the root-hypocotyle-cotyledon system.

• Korean Journal of Medicinal Crop Science
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• v.13 no.6
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• pp.273-277
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• 2005

Adventitious shoots were directly induced from leaf explants of R. glutinosa, an important medicinal plant. Proliferating shoot cultures were obtained by culturing leaf discs on Murashige and Skoog(MS) medium alone or combination with auxins and cytokinins. MS medium supplemented with 1 $mg/{\ell}\;BA\;and\;2\;mg/{\ell}$ IAA was the most effective, providing high shoot bud formation frequency without formation of intervening callus. The effect of leaf age on adventitious shoot formation was also investigated. The maximum shoot bud production (93.4%) was achived using 3rd leaf from apex of 6 weeks old plantlets after seed germination. Plantlet were rooted on an half-strength MS (1/2MS) medium containing 0.1 $mg/{\ell}\;IBA$. This prtocol is useful for clonal propagation and Agrobacterium-mediated transforamtion in R. glutinosa.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.464-467
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• 2001

In order to establish a in vitro propagation system for gold tree[Dendropanax morbifera $L_{EV}$], the effects of auxins and cytokinins on shoot multiplication and rooting were investigated. Germination rate was the best in MS medium. The fresh weight and number of shoot were the best on the medium containing 0.1 or 1.0 mg/l BAP and 0.5 or 1.0 mg/l NAA. Shoots were successfully rooted in MS medium with 1.0 mg/l NAA. Roots were easily formed by the addition of auxins, especially 0.1 or 1.0 mg/l BAP.P.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.3
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• pp.147-151
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• 1990

The purpose of this study is to clarify the relation of survival rates of seedling plants under grown orchardgrass populations and control by the difference cutting frequency. The orchardgrass populations investigated in this study have passed for 10 years after establishment. Cutting frequencies were 3, 4 and 5 times in a year. This experiment was conducted from April to October, 1989 at the experimental field of Institute of Agricultural Development, Yonsei University. The results are summarized as follows: 1. The survival rates of seedling plants decreased by the days after sowing. The final survival rates of seedling plants were 7.8%, 38.9% and 33.8% in 3, 4 and 5 cuttings, respectively. 2. Relative light intensity indicated highly possitive correlation with relative survival rates of seedling plants and negative correlation with plant length of orchardgrass populations in 4 and 5 cuttings. 3. The frequency distribution of survival seedling plants at 177 days after sowing were showed high values in seeding spots near the adjacent plants of 3 cutings, but in the middle of seeding spots between adjacent plants of 4 .and 5 cuttings, respectively. 4. The plant length of seedling became longer towards the seeding spots near the adjacent plants but the number of tillers increased slightly up to the middle of seeding spots between adjacent plants in all cutting frequencies.

• Journal of Life Science
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• v.13 no.1
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• pp.83-89
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• 2003

To investigate the function of chloroplast small heat shock protein (HSP), transgenic tobacco plants (Nicotiana tabacum L, cv. SR-1) that constitutively overexpress the rice chloroplast small HSP (Oshsp26) were generated. Effects of constitutive expression of the Oshsp26 on thermotolerance were investigated with the chlorophyll fluorescence. After 5-min incubation of leaf discs at high temperatures, an increase in the Fo level, indication of separation of LHCII from PSII, was mitigated by constitutive expression of the chloroplast small HSP When tobacco plantlets grown in Petri dishes were incubated at $20^{\circ}C$/TEX> for 45 min and subsequently incubated at $20^{\circ}C$/TEX> leaf color of wild-type plant became gradually white and all plantlets were finally died. Under the conditions in which all the wild-type plants died, more than 80% of the transformants remained green and survived. It was also found that the levels of Oshsp26 protein accumulated in transgenic plants were correlated with the degree of thermotolerance. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery, as a results, increases thermotolerance of whole plant during heat stress.

• Journal of Bio-Environment Control
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• v.8 no.1
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• pp.30-35
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• 1999

The purpose of this study was to evaluate the effect of temporary pH reductions on tuberization of ‘Dejima’potato in aeroponics. The pH and EC of nutrient solution were adjusted to 6.0∼6.5 and 1.2mS/cm, respectively. On 35th day after planting, plants were subjected to pH 3.0, 4.0, 5.0 and 6.5 for 10hrs. After 5 days mini-tuberization was shown in pH 3.0 treatment and was significantly increased up to 20 days. Temporary low pH treatment resulted in the increase of stolen formation and of tuber dry weight. Number of mini-tubers per plant on 90th-day after planting was 72.1, 69.8, 65.2, and 60.3 in pH 3.0, 4.0, 5.0 and 6.5 respectively.