• Title/Summary/Keyword: Root density

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A Study on the Growth Diagnosis and Management Prescription for Population of Retusa Fringe Trees in Pyeongji-ri, Jinan(Natural Monument No. 214) (진안 평지리 이팝나무군(천연기념물 제214호)의 생육진단 및 관리방안)

  • Rho, Jae-Hyun;Oh, Hyun-Kyung;Han, Sang-Yub;Choi, Yung-Hyun;Son, Hee-Kyung
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.36 no.3
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    • pp.115-127
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    • 2018
  • This study was attempted to find out the value of cultural assets through the clear diagnosis and prescription of the dead and weakness factors of the Population of Retusa Fringe Trees in Pyeongji-ri, Jinan(Natural Monument No. 214), The results are as follows. First, Since the designation of 13 natural monuments in 1968, since 1973, many years have passed since then. In particular, despite the removal of some of the buried soil during the maintenance process, such as retreating from the fence of the primary school after 2010, Second, The first and third surviving tree of the designated trees also have many branches that are dead, the leaves are dull, and the amount of leaves is small. vitality of tree is 'extremely bad', and the first branch has already been faded by a large number of branches, and the amount of leaves is considerably low this year, so that only two flowers are bloomed. The second is also in a 'bad'state, with small leaves, low leaf density, and deformed water. The largest number 1 in the world is added to the concern that the s coverd oil is assumed to be paddy soils. Third, It is found that the composition ratio of silt is high because it is known as '[silty loam(SiL)]'. In addition, the pH of the northern soil at pH 1 was 6.6, which was significantly different from that of the other soil. In addition, the organic matter content was higher than the appropriate range, which is considered to reflect the result of continuous application for protection management. Fourth, It is considered that the root cause of failure and growth of Jinan pyeongji-ri Population of Retusa Fringe Trees group is chronic syndrome of serious menstrual deterioration due to covered soil. This can also be attributed to the newly planted succession and to some of the deaths. Fifthly, It is urgent to gradually remove the subsoil part, which is estimated to be the cause of the initial damage. Above all, it is almost impossible to remove the coverd soil after grasping the details of the soil, such as clayey soil, which is buried in the rootstock. After removal of the coverd soil, a pestle is installed to improve the respiration of the roots and the ground with Masato. And the dead 4th dead wood and the 5th and 6th dead wood are the best, and the lower layer vegetation is mown. The viable neck should be removed from the upper surface, and the bark defect should undergo surgery and induce the development of blindness by vestibule below the growth point. Sixth, The underground roots should be identified to prepare a method to improve the decompression of the root and the respiration of the soil. It is induced by the shortening of rotten roots by tracing the first half of the rootstock to induce the generation of new roots. Seventh, We try mulching to suppress weed occurrence, trampling pressure, and soil moisturizing effect. In addition, consideration should be given to the fertilization of the foliar fertilizer, the injection of the nutrients, and the soil management of the inorganic fertilizer for the continuous nutrition supply. Future monitoring and forecasting plans should be developed to check for changes continuously.

Korean-Style No-tillage Organic Agriculture on Recycled Ridge IV. Changes in Soil Microorganisms and Enzymes by Split Irrigation and Organic Matter Application in Organic Farming of Red Pepper in Plastic Film Greenhouse (두둑을 재활용한 한국형 무경운 유기 농업 IV. 분할관수와 유기물처리에 의한 시설 고추 유기재배 토양 미생물상과 토양 효소의 변화)

  • Yang, Seung-Koo;Shin, Kil-Ho;Song, Yong-Su;Kim, Kil-Yong;Jung, Woo-Jin
    • Korean Journal of Organic Agriculture
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    • v.25 no.2
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    • pp.311-328
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    • 2017
  • This study was carried out to investigate the changes in soil microorganisms and soil enzymes by split irrigation and organic matter application under no-tillage green house conditions. Soil bacteria and fungi abundances were higher in soybean cake fertilizer than in the soil without the soybean cake fertilizer under whole quantity irrigation. Bacteria and fungi abundances in soil increased with increasing organic fertilizer application rate. Bacteria and fungi amount in the soil increased at half division irrigation in no-treatment of soybean cake fertilizer compared with whole quantity irrigation. Actinomycete amount in the soil decreased with increasing soybean cake fertilizer with whole quantity irrigation while clearly increased in no-treatment of soybean cake fertilizer. Actinomycete amount in soil clearly increased with increasing organic fertilizer input at half division irrigation. Chitinase activity in the soil decreased in soybean cake fertilizer with increasing organic fertilizer input, while increased in no-treatment of soybean cake fertilizer. Chitinase activity in the soil increased at half division irrigation compared with whole quantity irrigation regardless of soybean cake fertilizer input. ${\beta}$-Glucosidase activity in the soil was higher in soybean cake fertilizer than in no-treatment of soybean cake fertilizer with whole quantity irrigation. ${\beta}$-Glucosidase activity in the soil increased with increasing organic fertilizer input, but decreased in above the standard level 66%. ${\beta}$-Glucosidase activity in the soil clearly increased in no-treatment of soybean cake fertilizer at half division irrigation compared with whole quantity irrigation. N-acetyl-${\beta}$-D-glucosaminidase activity was higher in soybean cake fertilizer than in no-treatment of soybean cake fertilizer with whole quantity irrigation. N-acetyl-${\beta}$-D-glucosaminidase activity in the soil increased with increasing organic fertilizer input, but decreased in above the standard level 66%. N-acetyl-${\beta}$-D-glucosaminidase activity in the soil was not significantly different at half division irrigation and whole quantity irrigation in organic fertilizer input, while increased at half division irrigation in no-treatment of soybean cake fertilizer. Acid phosphatase activity increased at standard level 66% in soybean cake fertilizer, while was not significantly different in no-treatment of soybean cake fertilizer. Spore density of Arbuscular Mycorrhizal Fungi (AMF) in the soil increased with increasing organic fertilizer input at whole quantity irrigation in no-treatment of soybean cake fertilizer, while decreased above the standard level 66% in organic fertilizer input. However, spore density of AMF in the soil was not significantly different in soybean cake fertilizer regardless of input amount of organic fertilizer. Root colonization rate of AMF in red pepper roots was not significant difference at two irrigations regardless of soybean cake input.

The Variation of Natural Population of Pinus densiflora S. et Z. in Korea (VIII) - Genetic Variation of the progeny originated from Injye, Jeongsun, and Samchuk Populations - (소나무 천연집단(天然集團)의 변이(變異)에 관(關)한 연구(硏究) - 인제(麟蹄), 정선(旌善), 삼척집단(三陟集團)의 차대(次代)의 유전변이(遺傳變異) -)

  • Yim, Kyong Bin;Lee, Kyong Jae
    • Journal of Korean Society of Forest Science
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    • v.43 no.1
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    • pp.20-30
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    • 1979
  • The purpose of present study is to analyze the genetic variation of natural stand of Pinus densiflora. In 1976 following after the seletion of 1974 and 1975, twenty trees from each of three natural populations of the species were selected and seeds were collected, and the locations and conditions of populations are presented in table 1, 2 and figure 1. Some morphological traits of the populations were already detailed in our fifth report of this series. The morphological traits of cone, seed and seed-wing, and also the growth performances and needle characters of the seedling were observed in the present study according to the previous methods. The results obtained are summarized as follows; 1. The meteorological data obtained by averaging the records of 30 year period(1931~1960) measured from the nearest meteorological station to each population are shown in fig. 2, 3, 4. The distributional patterns of investigated climate factors are generally considered to be similar among the locations. However, the precipitation density during growing season and the air temperature during dormant season on Samchuk area (Pop. 9) were quite different from those of the other areas. 2. The measurements of fresh cone weight, length, diameter and cone index (i.e.: length to diameter ratio) are presented in table 7. As shown in table 7, all these traits except for cone diameter seem to be not significant in population and to be highly significant in family differences within population. 3. The morohological traits of seed and seed-wing are detailed in table 8, 9, and highly significant differences are recognized among the populations and the families within population in seed weight, seed length, seed thickness but not among the populations in the other observed traits. The values of correlation between the characteristics of cone and seed are presented in table 12. As shown, the correlation between cone length and seed wing length, between seed wing width and seed width were significantly positive in population 8 and 9 but in population 7. The positive correlations between seed length and seed width were calculated in all populations studied 4. Significant statistical differences among populations and families within population are observed in the growth performances of 1-0 seedling height of these progenies. But the differences in 1-1 seedling height and root collar diameter are shown only among familes within population. As shown in table 13, the most parts of correlations are not significant statistically between the growth performances of seedling and the seed characters. 5. As shown in table 15, statistical differences are considered to be significant among the populations in stomata row on both sides of the needle but not in serration density. The correlations between progenies and parents are not generally observed in the investigated traits of needle as shown in table 16.

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The Variation of Natural Population of Pinus densiflora S. et Z. in Korea (III) -Genetic Variation of the Progeny Originated from Mt. Chu-wang, An-Myon Island and Mt. O-Dae Populations- (소나무 천연집단(天然集團)의 변이(變異)에 관(關)한 연구(硏究)(III) -주왕산(周王山), 안면도(安眠島), 오대산(五臺山) 소나무집단(集團)의 차대(次代)의 유전변이(遺傳變異)-)

  • Yim, Kyong Bin;Kwon, Ki Won
    • Journal of Korean Society of Forest Science
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    • v.32 no.1
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    • pp.36-63
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    • 1976
  • The purpose of this study is to elucidate the genetic variation of the natural forest of Pinus densiflora. Three natural populations of the species, which are considered to be superior quality phenotypically, were selected. The locations and conditions of the populations are shown in table 1 and 2. The morphological traits of tree and needle and some other characteristics were presented already in our first report of this series in which population and family differences according to observed characteristics were statistically analyzed. Twenty trees were sampled from each populations, i.e., 60 trees in total. During the autumn of 1974, matured cones were collected from each tree and open-pollinated seeds were extracted in laboratory. Immediately after cone collection, in closed condition, the morphological characteristics were measured. Seed and seed-wing dimensions were also studied. In the spring of 1975, the seeds were sown in the experimental tree nursery located in Suweon. And in the April of 1976, the 1-0 seedlings were transplanted according to the predetermined experimental design, randomized block design with three replications. Because of cone setting condition. the number of family from which progenies were raised by populations were not equal. The numbers of family were 20 in population 1. 18 in population 2 and 15 in population 3. Then, each randomized block contained seedlings of 53 families from 3 populations. The present paper is mainly concerned with the variation of some characteristics of cone, seed, needle, growth performance of seedlings, and chlorophyll and monoterpene compositions of needles. The results obtained are summerized as follows. 1. The meteorological data obtained by averaging the records of 30 year period, observed from the nearest station to each location of populations, are shown in Fig. 3, 4, and 5. The distributional pattern of monthly precipitation are quite similar among locations. However, the precipitation density on population 2, Seosan area, during growing season is lower as compared to the other two populations. Population 1. Cheong-song area, and population 3, Pyong-chang area, are located in inland, but population 2 in the western seacoast. The differences on the average monthly air temperatures and the average monthly lowest temperatures among populations can hardly be found. 2. Available information on the each mother trees (families) studied, such as age, stem height, diameter at breast height, clear-bole-length, crown conditions and others are shown in table 6,7, and 8. 3. The measurements of fresh cone weight, length and the widest diameter of cone are given in Tab]e 9. All these traits arc concerned with the highly significant population differences and family differences within population. And the population difference was also found in the cone-index, that is, length-diameter ratio. 4. Seed-wing length and seed-wing width showed the population differences, and the family differences were also found in both characteristics. Not discussed in this paper, however, seed-wing colours and their shapes indicate the specificity which is inherent to individual trees as shown in photo 3 on page 50. The colour and shape are fully the expression of genetic make up of mother tree. The little variations on these traits are resulted from this reason. The significant differences among populations and among families were found in those characteristics, such as 1000-seed weight, seed length, seed width, and seed thickness as shown in table 11. As to all these dimensions, the values arc always larger in population 1 which is younger in age than that of the other two. The population differences evaluated by cone, seed and seed-wing sizes could partly be attributed to the growth vigorousity. 5. The values of correlation between the characteristics of cone and seed are presented in table 12. As shown, the positive correlations between cone diameter and seed-wing width were calculated in all populations studied. The correlation between seed-wing length and seed length was significantly positive in population 1 and 3 but not in population 2, that is, the r-value is so small as 0.002. in the latter. The correlation between cone length and seed-wing length was highly significant in population 1, but not in population 2. 6. Differences among progenies in growth performances, such as 1-0 and 1-1 seedling height and root collar diameter were highly singificant among populations as well as families within population(Table 13.) 7. The heritability values in narrow sense of population characteristics were estimated on the basis of variance components. The values based on seedling height at each age stage of 1-1 and 1-0 ranged from 0.146 to 0.288 and the values of root collar diameter from 0.060 to 0.130. (Table 14). These heritability values varied according to characteristics and seedling ages. Here what must be stated is that, for calculation of heritability values, the variance values of population was divided by the variance value of environment (error) and family and population. The present authors want to add the heritability values based on family level in the coming report. It might be considered that if the tree age is increased in furture, the heritability value is supposed to be altered or lowered. Examining the heritability values studied previously by many authors, in pine group at age of 7 to 15, the values of height growth ranged from 0.2 to 0.4 in general. The values we obtained are further below than these. 8. The correlation between seedling growth and seed characteristics were examined and the values resulted are shown in table 16. Contrary to our hypothetical premise of positive correlation between 1-0 seedling height and seed weight, non-significance on it was found. However, 1-0 seedling height correlated positively with seed length. And significant correlations between 1-0 and 1-1 seedling height are calculated. 9. The numbers of stomata row calculated separately by abaxial and adaxial side showed highly significant differences among populations, but not in serration density. On serration density, the differences among families within population were highly significant. (Table 17) A fact must be noted is that the correlation between stomata row on abaxial side and adaxial side was highly significant in all populations. Non-significances of correlation coefficient between progenies and parents regarding to stomata row on abaxial side were shown in all populations studied.(Table 18). 10. The contents of chhlorophyll b of the needle were a little more than that of chlorophyll a irrespective of the populations examined. The differences of chlorophyll a, b and a plus b contents were highly significant but not among families within populations as shown in table 20. The contents of chlorophyll a and b are presented by individual trees of each populations in table 21. 11. The occurrence of monoterpene components was examined by gas liquid chromatography (Shimazu, GC-1C type) to evaluate the population difference. There are some papers reporting the chemical geography of pines basing upon monoterpene composition. The number of populations studied here is not enough to state this problem. The kinds of monoterpene observed in needle were ${\alpha}$-pinene, camphene, ${\beta}$-pinene, myrcene, limonene, ${\beta}$-phellandrene and terpinolene plus two unknowns. In analysis of monoterpene composition, the number of sample trees varied with population, I.e., 18 families for population 1, 15 for population 2 and 11 for population3. (Table 22, 23 and 24). The histograms(Fig. 6) of 7 components of monoterpene by population show noticeably higher percentages of ${\alpha}$-pinene irrespective of population and ${\beta}$-phellandrene in the next order. The minor Pinus densiflora monoterpene composition of camphene, myrcene, limonene and terpinolene made up less than 10 percent of the portion in general. The average coefficients of variation of ${\alpha}$-pinene and ${\beta}$-phellandrene were 11 percent. On the contrary to this, the average coefficients of variation of camphene, limonene and terpinolene varied from 20 to 30 percent. And the significant differences between populaiton were observed only in myrcene and ${\beta}$-phellandrene. (Table 25).

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Origin and Storage of Large Woody Debris in a Third-order Mountain Stream Network, Gangwon-do, Korea (강원도 산지계류 내 유목의 기원과 현존량)

  • Kim, Suk Woo;Chun, Kun Woo;Seo, Jung Il;Lim, Young Hyup;Nam, Sooyoun;Jang, Su Jin;Kim, Yong Suk;Lee, Jae Uk
    • Korean Journal of Environment and Ecology
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    • v.34 no.3
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    • pp.249-258
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    • 2020
  • This study aims to provide reference material for effective forest management techniques at the catchment scale, based on the field investigation of large woody debris (LWD) in 11 streams within a third-order forest catchment in Gangwon Province, Korea. To achieve this aim, we analyzed the morphological features of LWD pieces, and the storage and distribution status of LWD by stream order throughout the entire investigation. As a result, a total of 1,207 individual pieces of LWD were categorized into three types as follows: (ⅰ) 1,142 pieces (95%) as only trunk and 65 pieces (5%) as a trunk with root wad, (ⅱ) 1,015 pieces (84%) as non-thinned and 192 pieces (16%) as the thinned, and (ⅲ) 1,050 pieces (87%) as conifer and 157 pieces (13%) as broadleaf. Additionally, in-stream LWD loads (㎥/ha) decreased with increasing stream order, yielding 105.4, 71.3, and 35.6 for first-, second-, and third-order streams, respectively. On the other hand, the ratio of LWD jams to the total LWD volume increased with increasing stream order, yielding 11%, 43%, and 49% for first-, second-, and third-order streams, respectively. Finally, a comparison of the in-stream LWD load with previous studies in several countries around the world indicated that in-stream LWD load was positively correlated with forest stand age even though the climate, topography, forest soil type, forest composition, stand growth rate, disturbance regime, and forest management practices were different. These results could contribute to understanding the significance of LWD as a by-product of forest ecosystems and an indicator of riparian forest disturbance. Based on this, we conclude that advanced forest management techniques, including treatment of thinning slash and stand density control of riparian forest by site location (hillslope and riparian zone, or stream order), should be established in the future, taking the forest ecosystem and the aquatic environment from headwater streams to low land rivers into consideration.

Effect of LED Light Intensity on Seedling Quality and Tuber Production of Potato Stem Cuttings Grown in a Closed-Type Plant Production System (폐쇄형식물생산시스템을 이용한 감자 경삽묘 육묘시 묘소질과 괴경 생산에 대한 LED 광도의 영향)

  • Jo, Man Hyun;Ham, In Ki;Park, Kwon Seo;Cho, Ji Hong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.65 no.4
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    • pp.468-476
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    • 2020
  • This study was performed to establish light intensity conditions for producing stem cuttings for aeroponic systems suitable for seed potato production using a closed-type plant production system. Shoot tip cultured plantlets of 'Sumi' and 'Chubaek' potato (Solanum tuberosum L.) were acclimatized, cuttings were collected, and stem cuttings were planted. The seedlings were raised for 40 days at different LED light intensities (60, 120, 180, and 240 μmol·m-2·s-1), and were cultivated in an aeroponic system for 80 days. When stem cuttings were raised at 60 μmol·m-2·s-1 LED light intensity, the plant height was the longest, at 17.3 cm for 'Sumi' and 16.1 cm for 'Chubaek', and the number of nodes was the highest in both cultivars. The higher light intensities, produced smaller plants with fewer nodes. The leaf areas, SPAD values, and Fv/Fm values differed slightly between cultivars. The fresh weight of stem cuttings, and the production rate of healthy stem cuttings were the highest at 60 μmol·m-2·s-1. In the aeroponic system, seedlings raised at 60 μmol·m-2·s-1 with LED light intensity showed a difference between the cultivars, but the fresh weight of stems and leaves above the planting plate was the heaviest. In addition, below the planting plate the stem cuttings were longest and the root weight was heaviest at 60 μmol·m-2·s-1 LED light intensity. The number of stolons also differed between cultivars, but was greatest for seedlings raised at 60 μmol·m-2·s-1 LED light intensity, at 4.2/plant for 'Sumi' and 7.7/plant for 'Chubaek'. At 60 μmol·m-2·s-1 LED light intensity, the tuber number and total tuber weight were the best, but the higher the light intensity, the smaller the total tuber number and total tuber weight for both cultivars. In conclusion, when producing potato stem cuttings for aeroponic systems using a closed-type plant production system, the most suitable LED light intensity for raising seedlings was found to be 60 μmol·m-2·s-1.

Studies on the Indigenous Vesicular-Arbuscular Mycorrhizal Fungi(VAMF) in Horticultural Crops Grown Under Greenhouse -I. Spore Density and Root Colonization of the Indigenous VAMF in Soil of Some Horticultural Crops (시설원예(施設園藝) 작물(作物)에서 토착(土着) VA균근균(菌根菌)에 관한 연구(硏究) -I. 감염양상(感染樣相)과 밀도(密度))

  • Sohn, Bo-Kyoon;Huh, Sang-Man;Kim, Kwang-Sik
    • Korean Journal of Soil Science and Fertilizer
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    • v.24 no.3
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    • pp.225-233
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    • 1991
  • This study was conducted to evaluate the potential of indigenous vesicular-arbuscular mycorrhizal fungi(VAMF) in the rhizosphere soil of horticultural crops grown under greenhouse and open-field condition, in the southern area of Kores. Soil samples collected from the rhizosphere of some sellected horticultural crops, such as cucumber, hot pepper, lettuca, tomato and eggplant grown under greenhouse or open-field condition. All tested crops are considered as mycorrhizal plants. The infection rate of horticultural crops investigated ranged from 38% to 70%, hot pepper and eggplant grown under greenhouse condition showed the highest infection being 66.0% and 70.0%, respectively. Spore densities were from 4.8 to 20.0g-1 on dried soil basis. Spore densities of VAMF in the rhizosphere soils under greenhouse condition were higher than that of open-field conditions. The highest distribution of spores in diameter ranged from $75{\mu}m$ to $106{\mu}m$ in the rhizosphere soil of lettuce, cucumber and tomato while those in hot pepper and eggplant ranged from $75{\mu}m$ to $250{\mu}m$. Glomus sp.-type spores predominated in the slightly acid soil(pH 6.3), while Acaulospora sp.-type spores greatly predominated in the very strongly acid field(pH 4.9).

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Studies on Amelioration of Soil Physico-Chemical Properties and Rice Yield in Sandy Tidal Saline Paddy Soil (사질(砂質) 염해답(鹽害畓)에서 개량제(改良劑) 시용(施用)이 토양(土壤)의 물리화학성(物理化學性) 변화(變化)와 수도수량(水稻收量)에 미친 영향(影響))

  • Yoo, Chul-Hyun;Kim, Jong-Gu;Choi, Song-Yeol;Cho, Guk-Hyun;Yoo, Sug-Jong;So, Jae-Dong;Rhee, Gyeong-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.26 no.4
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    • pp.241-248
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    • 1993
  • An experiment was conducted in 1990~1991 to study the effects of various soil amelioration on the soil productivity and machine workability at tidal land paddy field of Kyewhado Substation, Homam Crop Experiment Station. The soil, Munpo Series(fine sandy loam, Typic Fluvaquents) was treated with gipsum, rice straw, rice straw compost and foreign soil(at 20cm depth) after deep ploughing. The results are surmerized as follows. 1. Sand and clay were slightly increased, while silt was slightly decreased in the rice straw and compost plots. The soil texture was changed from loam to sand loam by the addition of foreign soil 2. Soil bulk density and porosity was decreased in the rice straw, compost and foreign soil addition plots. 3. Cone penetration resistance was $12.5kg/cm^2$ at 10cm of soil depth before experiment and $12.5kg/cm^2$ at 20cm of soil depth after experiment except control, and the root zone was expended down to 20cm. 4. Soil salt content before experiment was 0.46 and 0.48% for surface soil(10cm) and subsoil(20cm), respectively ; The salt content of ameliorated plot was 0.26~0.32% and 0.16~0.31%, respectively, indicating good leaching of soil salt by the soil improvements. 5. The yields of rice in different treatments were in the order of the foreign soil addition > compost > gypsum > rice straw > control.

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PERIPHERAL NERVE REGENERATION USING POLYGLYCOLIC ACID CONDUIT AND BRAIN-DERIVED NEUROTROPHIC FACTOR GENE TRANSFECTED SCHWANN CELLS IN RAT SCIATIC NERVE (BDNF 유전자 이입 슈반세포와 PGA 도관을 이용한 백서 좌골신경 재생에 관한 연구)

  • Choi, Won-Jae;Ahn, Kang-Min;Gao, En-Feng;Shin, Young-Min;Kim, Yoon-Tae;Hwang, Soon-Jeong;Kim, Nam-Yeol;Kim, Myung-Jin;Jo, Seung-Woo;Kim, Byung-Soo;Kim, Yun-Hee;Kim, Soung-Min;Lee, Jong-Ho
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.30 no.6
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    • pp.465-473
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    • 2004
  • Purpose : The essential triad for nerve regeneration is nerve conduit, supporting cell and neurotrophic factor. In order to improve the peripheral nerve regeneration, we used polyglycolic acid(PGA) tube and brain-derived neurotrophic factor(BDNF) gene transfected Schwann cells in sciatic nerve defects of SD rat. Materials and methods : Nerve conduits were made with PGA sheet and outer surface was coated with poly(lactic-co-glycolic acid) for mechanical strength and control the resorption rate. The diameter of conduit was 1.8mm and the length was 17mm Schwann cells were harvested from dorsal root ganglion(DRG) of SD rat aged 1 day. Schwann cells were cultured on the PGA sheet to test the biocompatibility adhesion of Schwann cell. Human BDNF gene was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into E1 deleted region of adenovirus shuttle vector, pAACCMVpARS. BDNF-adenovirus was multiplied in 293 cells and purified. The BDNF-Adenovirus was then infected to the cultured Schwann cells. Left sciatic nerve of SD rat (250g weighing) was exposed and 14mm defects were made. After bridging the defect with PGA conduit, culture medium(MEM), Schwann cells or BDNF-Adenovirus infected Schwann cells were injected into the lumen of conduit, respectively. 12 weeks after operation, gait analysis for sciatic function index, electrophysiology and histomorphometry was performed. Results : Cultured Schwann cells were well adhered to PGA sheet. Sciatic index of BDNF transfected group was $-53.66{\pm}13.43$ which was the best among three groups. The threshold of compound action potential was between 800 to $1000{\mu}A$ in experimental groups which is about 10 times higher than normal sciatic nerve. Conduction velocity and peak voltage of action potential of BDNF group was the highest among experimental groups. The myelin thickness and axonal density of BDNF group was significantly greater than the other groups. Conclusion : BDNF gene transfected Schwann cells could regenerate the sciatic nerve gap(14mm) of rat successfully.

Studies on the Cause and Control for Non-sprouting Bud in the Utility Reclaimed Hill Side Mulberry Field. (개간지 상전에 발생하는 발아불량 현상의 원인 및 방제에 관한 연구)

  • 유근섭
    • Journal of Sericultural and Entomological Science
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    • v.16 no.1
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    • pp.1-20
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    • 1974
  • These studies are conducted to find out inducing factors for the non-sprouting bud which appears in the utility reclaimed hill mulberry held and to establish control method for it since 1971. The results are as follows: 1. In spring, winter bud does not germinate at all on the top of branches or does wither suddenly after or during its germination. Necrosis and browning are appeared in cortex and phloem of non-sprouting bud branch. In autumn, the deterioration of leaves, the abnormal leaves on the top of branch, and browning of veins or petioles are also observed. 2. The soil of non-sprouting bud mulberry Held were found to be sand loom derived from granite rocks. The sub soil of it was very poor in development of root system because it had hard soil and lower pore space ratio. Especially, the sub soil to bring about severe non-sprouting bud had been easily appeared with deficiency of moisture content because of high density solid. 3. Content of soil moisture was significantly lower in the severe non-sprouting bud soil than in the healthy field. The sub soil o( the healthy field contained proper moisture content. On the other hand, the sub soil of the severe non-sprouting bud held contained almost critical moisture content for wilting. 4. The depth of available soil was shallow in the non-sprouting bud than in the healthy fold. The more rate of the non-sprouting bud was severe, the more available soil depth was sallow. 5. Available boron content in soil was affected by moisture content in soil. There was. lower moisture content in the non-sprouting bud field than that in healthy fold during 5, June to 5, September. 6. There was no significant correlation between soil pH and available boron content. On the other hand, the correlation of the content of organic matter and available boron content appeared to be highly positive significance. 7. The quantity of boron was significantly contained more in healthy mulberry field (0.34∼0.43ppm) than in non-sprouting bud field (0.10∼0.28ppm). 8. Boron content in leaves and barks was significantly lower in the non-sprouting bud trees than in healthy trees. 9. The symptom of non-sprouting bud induced from boron free sand culture was similar with that arised in the non-sprouting bud field. 10. The rate of non-sprouting bud was high by the increased application of lime. Considering the facts mentioned the above, author may conclude that the non-sprouting bud of mulberry tree is caused by boron deficiency, but also it is affected by the parent rocks, organic matter, soil moisture content and lime application. 11. The non$.$sprouting bud may be completely controlled by the application of 6∼9kg borax per 10a mulberry field twice a year in spring and summer.

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