• Journal of Plant Biology
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• v.35 no.3
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• pp.211-217
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• 1992

In order to elucidate the formation of reaction tissues during the transition from primary to secondary growth, the developmental anatomy was conducted in the first internode of Acer sacchan'num seedling in horizontal position. During the transition from primary to secondary growth, tension wood(gelatinous fiber) was gradually developed on the upper side only, And the tension wood formation in the upper side of the horizontal first internode proceeds acropetally from base to apical portion. Some of the anatomical features of tension wood start to be in the primary vascular tissue and a typical tension wood show during the secondary growth, Therefore, the procambium seems to respond to the gravity as well as vascular cambium. For this reason, both procambium and vascular cambium has to regard as the same meristem, On the other hand, the upper side vessels were longer than those of the lower side in the horizontal first internode. The lateral-wall pitting of vessel elements, however, showed no differences between upper and lower sides which have alternate type. The width and height of rayon the upper side of horizontal first internode was larger as compared with the lower side.r side.

• Journal of Life Science
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• v.18 no.2
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• pp.154-161
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• 2008

The physiological and photochemical responses of rice seedling to NaCl stress were investigated through measuring leaf relative water content (RWC), root water uptake and chlorophyll fluorescence. When plants were exposed to increased salinity stress, the visual symptoms of injury were significant at ${\geq}$500 mM NaCl concentration for 4 and 5 day stress periods. The differences in Fv/Fm between control treatment and plants treated with 500 mM and 1,000 mM NaCl were evident after 5 day and 4 day, respectively, whereas in root water uptake its effect was observed at 500 mM and 1,000 mM NaCl at 2 day of salt-stressed periods. Leaf RWC in salt-stressed plants decreased gradually with increasing salinity in exogenous solution and duration of salt stress, and these decrease showed leaf RWC of 58-68% atduration over 2 day stress of 1,000 mM NaCl treatment and 88% at 1 day stress. NaCl stress led to a significant inhibition of the light-induced greening in etiolated rice plants, especially in 4 and 5 day salt-stressed plants, which linearly decreased with NaCl concentration ($R^2$=0.812 and 0.918, respectively). The effects of NaCl stress in rice seedlings indicate that water uptake in root is more sensitive to increasing NaCl concentration and stress duration than Fv /Fm in leaves compared with the same NaCl concentration.

• Korean Journal of Environmental Biology
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• v.23 no.1
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• pp.52-56
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• 2005

Eight days grown barley seedlings were treated with dimethipin for 72 hours and then the content of chlorophyll and photosynthetic electron activities of isolated chloroplasts were investigated. At the treatment of 10/sup -5/ M dimethipin the content of chlorophyll was decreased to 33% at 72 hours. Seven days etiolated barley seedlings were exposed to the light while dimethipin was added. At the time of 48 hours' greening chlorophyll content was reduced to 43% at 10/sup -4/M dimethipin and the chlorophyll a/b ratio was increased. In photosynthetic electron transport the activity of PSⅡ+PSⅠ was decreased to 10% at 48 hours and 25% at 72 hours at 10/sup -4/ M dimethipin. In the treatment of 10/sup -4/ M dimethipin the activity of PSⅡ+PSⅠ, except water splitting system was inhibited to 16% at 48 hours and 27% at 72 hours. The activity of PSⅡ was inhibited to 8% at 24 hours, 13% at 48 hours and 18% at 72 hours at 10/sup -4/ M dimethipin. The activity of PSⅠ was inhibited to 4% at 24 hours, 8% at 48 hours and 10% at 72 hours at 10/sup -4/ M dimethipin. In the times of greening of 7 days etiolated barley seedlings the activities of PSⅡ+PSⅠ were reduced to 5, 10, 10 and 11 % at 6, 12, 24, and 48 hours, respectively, at 10/sup -4/ M dimethipin. On the other hand, the activity of PSⅡ+PSⅠ except water splitting system, was not inhibited at all incubated hours in 10/sup -4/M dimethipin and there were no clear changes of the activities of PSⅡ and PSⅠ as compared to the control. Therefore, it could be concluded that dimethipin inhibited the photosynthetic electron activity by affecting the function of chloroplast rather than the synthesis of chloroplast and the inhibited function of chloroplast seems to come from the severe decrease of chlorophyll content.

• Journal of Ginseng Research
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• v.28 no.4
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• pp.211-214
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• 2004

This study was carried out to find out the optimum hardening condition for ginseng plantlets redifferentiated by tissue culture method. While a lot of root hair were observed on the root of seedling grown on the soil, few root hair were observed on the root of plantlet redifferentiated in vitro. On the medium solidified with $0.1{\%}$ phytagel, root hair was not observed and root weight, root width and laternal root development were also very poor. While raising the phytagel concentration on the media, root hair began to increase and root weight, root width and latemal root development were improved. Vascular tissue of plantlet grown on the medium with $0.1{\%}$ phytagel was very poor, but that of plantlet grown on the medium with $0.8{\%}$ phytagel was very good.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.1
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• pp.73-83
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• 1995

Effect of water treatment sludge(alum sludge) application on the growth of Korea local corn(Zeas Mays L.) was evaluated and phytotoxicity of alum sludge on the growth of corn roots and plant height was tested. Alum sludge itself and composted alum sludge compost were applicated by 1500kg/ha in the plot respectively. For the fertility test, yield, chlorophyll content, plant height of corn treated by alum sludge and composted alum sludge were better than that of control. No clear toxixity of alum sludge was found. At the food chemical analyses of seed corn, no obvious component variation were evaluated either. Test of pH effect on phytotoxicity of alum sludge on corns showed that plant height and root growth of corns were inhibited at low pH 4 solution. Phytotoxicity test of alum sludge extract which was extracted at various pH solutions, showed that growth and cations uptake inhibition were found the more serious the lower the pH. Plant height and root growth injury were serious at higher than 100ppm Al content solution.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.217-223
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• 2002

초대형부유식 해상구조물의 안전성 확보를 위한 방파제 설계를 수행하여 그 효용성을 검증하고 관련 구조물의 설계에 대한 지침을 제공하였다. 초대형부유식 구조물의 설치 위치에 따라 파랑 하중을 계산하였고, 이 하중에 대한 최적의 직립식 방파제 단면을 통용되고 있는 Goda 식에 의하여 scantling 하였다. 케이슨의 안전성 검증을 위하여 유한요소해석을 수행하였고, 최종적으로 VLFS의 안전성 확보를 위한 하나의 방파제 설계도를 제시하였다.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.1
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• pp.73-79
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• 1996

골수나 유산물질에 대한 세포유전학적 검사에 있어 통상적인 염색체검사는 검사에 적합한 중기핵상을 얻기 어려워 실패하는 경우가 많다. 이러한 경우에 진단이나 치료에 도움을 줄 수 있는 방법으로 유식세포분리기를 사용하여 단일 세포내 DNA량에 따른 aneuploidy를 추적할 수 있는 가를 확인하기 위해 본 실험을 실시하였다. 79 (혈액 30, 골수 37, 유산물 12)예에서 염색체 검사와 유식세포 분리검사를 동시에 실시하여 각각의 결과를 비교한 결과 79.7% (63/79)의 일치율을 얻었다. 그러나 염색체의 손실이 없는 전좌와 역위의 경우는 물론 작은 조각의 염색체 부분이 늘어나거나 줄어든 경우에 있어서는 유식세포분리방법에 의해서 추적되지 못하였지만, 염색체 검사의 결과를 얻는데 실패한 경우에는 유식세포분리방법이 DNA량의 변화에 대한 정보를 얻을 수 있다는 것을 확인할 수 있었다. 따라서 본 연구결과는 세포유전학적 검사에서 유식세포분리방법이 염색체 검사보다 신속하며 염색체검사가 불가능한 시료에서도 DNA양에 따른 aneuploidy의 추적이 가능하다는 것을 시사한다.

• Journal of Plant Biology
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• v.35 no.4
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• pp.359-364
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• 1992

The vascular cambium in Ginkgo biloba seedling began to differentiate in the cotyledonary node, and then the differentiation proceeded bidirectionally from the cotyledonary node toward the stem and root. In tangential view, procambium at the early developmental stage was a homogeneous structure consisted of almost similar cells in shape, and at the later stage the procambium became a heterogeneous one consisted of long cells and short cells. Such a differentiation pattern in the cotyledonary node was similar to that in the stem. However, it was different from that in the root. Fusiform initials and ray initials consisting the vascular cambium were originated from the long cells and the short cells, respectively. The long cells and the fusiform initials in the cotyledonary node were shorter and wider than those in the first internode.ernode.

• Journal of Plant Biology
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• v.34 no.4
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• pp.283-288
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• 1991

This work was carried out to determined the effect of 2,4-dinitrophenol(DNP) on in vivo nitrate reductase activity in the root of 6 day old rye (Secale cereale L.) seedlings. The nitrate reductase activity in the roots of 6 day old rye seedlings pretreated with 0.5 mM DNP was higher than that of the control group in all the experimental conditions. The optimal concentration of KNO3 for maximum nitrate reductase activity was 10 mM in both control and treated group. The nitrate reductase activity in the treatment of 10 mM KNO3 gradually increased for 4 h in both groups, and then maintained constantly. The nitrate reductase activity occurred per hour was highest at 1 h in both groups, while it was declined by large degrees as time goes on. The daily pattern of nitrate reductase activity was gradually decreased in both groups with the passage of day. The optimal pH for this experiment and a previous paper (Kwon et al., 1991), it was determined that the nitrate reductase activity in both roots and shoots of rye seedlings was increased by the treatment of 0.5 mM DNP, and particulary in both groups, the nitrate reductase activity in the roots of rye seedlings was higher than that in shoots of them.

• Korean Journal of Plant Tissue Culture
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• v.22 no.3
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• pp.165-168
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• 1995

The embryos formed from anther culture of peony exhibited divergent morphologies. The frequency of normal embryos with two cotyledons was about two times higher in the embryos formed through direct embryogenesis than those formed from callus. About 69% of the embryos with two cotyledons converted into normal plants, but convention rate of the abnormal embryos with one and three or four cotyledons was only 4 to 9%. The embryos of hem and bowling pin shape did not undergo development into normal plants.