• Structural Monitoring and Maintenance
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• v.7 no.1
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• pp.43-58
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• 2020

Pile foundations of existing bridges lie in soil and water environment for long term and endure relatively heavy vertical loads, thus prone to damages, especially after stricken by external forces, such as earthquake, collision, soil heap load and etc., and the piles may be injured to certain degrees as well. There is a relatively complete technical system for quality inspection of new bridge pile foundations without structures on the top. However, there is no mature technical standard in the engineering community for the non-destructive testing technology specific to the existing bridge pile foundations. The quality of bridge pile foundations has always been a major problem that plagues bridge maintenance. On the basis of many years' experiences in test engineering and theoretical studies, this study developed a new type of detection technology and equipment for the existing bridge piles.

• Journal of Korean Society of Forest Science
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• v.80 no.4
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• pp.416-419
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• 1991

Effective micropropagation was achieved by axillary bud culture from stool shoots of 15-year-old Betula platyphylla var. japonica. Shoot development and proliferation from the explants were successful on WPM supplemented with 0.5 or 1.0mg/l BAP. All the regenerated shoots rooted when transfered to GD medium containing 0.2mg/l IBA. After transplaning to soil more than 95% of the plantlets survived and showed normal growth. The results demonstrate that masspropagation of selected mature trees is feasible using tissue culture technique.

• Journal of Plant Biology
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• v.36 no.3
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• pp.211-218
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• 1993

Plant regeneration was accomplished from protoplast culture of rice (Oryza sativa L. cv. Taebaeg). Embryogenic callus was induced from mature seed on MS medium containing 5 mM proline, 2.5 mg/L 2,4-D, 30 g/L sucrose in the dark at 28$^{\circ}C$ and used to establish embryogenic cell suspension culture. Suspension cells were subcultured every one week in N6 medium supplemented with 5 mM proline, 200 mg/L casein hydrolysate, 2.5 mg/L 2,4-D and amino acids of AA medium. Suspension cultures were composed of cells that were densely cytoplasmic, potentially embryogenic and were at least maintained for more than 6 months in liquid medium. Protoplasts were isolated from fast-growing suspension culture cells and cultured in a slightly modified KpR medium by mixed nurse culture. Isolated protoplasts began to divide within 5~7 days and thereafter, protoplast-derived calli were sequentially transferred to callus proliferating medium that soft agar MS medium contained 2 mg/L 2,4-D and produced distinct embryogenic cells. Microcolonies were then transferred to solid medium which consisted of MS medium containing 5 mg/L kinetin, 1 mg/L NAA, 1 mg/L ABA, 30 g/L sucrose and 10 g/L sorbitol under fluorescent light. Mulitple shoots of 4~5 per callus emerged and were transferred to hormone-free MS medium for root initiation. Thereafter, The plantlets were transferred to pots of soil to mature in the culture room.

• Korean Journal of Plant Tissue Culture
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• v.26 no.4
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• pp.271-274
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• 1999

This study was undertaken to develop an efficient propagation technique for mature Betula davurica. Using aseptic materials taken from in vitro culture, the effects of media and plant growth regulators on shoot proliferation and rooting were investigated. DKW medium turned out to be the best in shoot proliferation among the media tested. Whereas axillary buds were better culture material than apical buds in proliferation of shoots, apical buds were slightly better than axillary buds on shoot elongation. Neither 1 /2 MS nor WPM medium seemed to be suitable for shoot multiplication or elongation. When the explants were cultured on 1/2 MS medium, shoot elongation was retarded by forming big callus at the base. In the case of WPM, shoots could be formed normally, but they exhibited slow growing. NAA was so effective on in vitro rooting that more than 80% rooting could be achieved on half-strength DKW medium supplemented with 1.0 mg/L NAA after 4 weeks in cultures. Ex vitro rooting using elongated shoot was also applicable to rooting and acclimatization. Rooted plantlets were successfully acclimatized in an artificial soil mixture and grew normally. The results demonstrate that efficient mass propagation of mature B. davurica can be done through tissue culture.

• Journal of Plant Biology
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• v.11 no.3
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• pp.1-7
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• 1968

Organic matter in rice-paddy soils exercises two antagonistic effects on the rice plant under water-logged conditions in growing season in the course of its decomposition: It liberates mineral nutrients and promotes soil fertility. On the other hand, however, it demands oxygen for its decay and therefore competes with rice roots for this element, when applied in large quantity of fresh status. For the practical end of rice culture, it is most desirable that these two effects should not contend with each other. To determine the proper content of organic materials to be applied, the influences of varied amounts of a homogeneous mixture of dried green manure, ranging from 0 to 20g/pot (1/20,000 tanbo), upon hte growth of rice was investigated in a sand culture. Labeled phosphorus fertilizer was also used in the form of KH232PO4 to evaluate the availability of this nutrient in the soil. Under the present experimental conditions, green mature seems to have influenced little on the growth of rice, except on number of grains produced and grains/straw ratio. Moreover, no sympton of growth inhibition is obsrvable even by the largest amount of its application. The available phosphorus, as estimated by A-value, appears to have increased, as the amount of organic materials applied increases. In view of the fact that pure sand instead of a paddy soil is used in this culture, the present results would not be directly applicable to practical rice farming. Besides, the estimated A-value is in need of further study, since it varies according to method of application, as suggested by Nishigki et. al. (1958).

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.454-462
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• 2018

Yield and grade are the key factors that affect production value of peanut. The objective of this study was to identify QTLs for pod yield, hundred-seed weight, and total sound mature kernel (TSMK). A total of 90 recombinant inbred lines, derived from Tamrun OL07 and a breeding line Tx964117, were used as a mapping population and planted in Brownfield and Stephenville, Texas. A genetic map was developed using 1,211 SNP markers based on double digest restriction-site associated DNA sequencing (ddRAD-seq). A total of 10 QTLs were identified above the permutation threshold, three for yield, three for hundred-seed weight and four for TSMK, with LOD score values of 3.7 - 6.9 and phenotypic variance explained of 12.2% - 35.9%. Among those, there were several QTLs that were detected in more than one field experiment. The commonly detected QTLs in this study may be used as potential targets for future breeding program to incorporate yield and grade related traits through molecular breeding.

• Economic and Environmental Geology
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• v.55 no.5
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• pp.439-445
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• 2022

Organic pollutants that contained in stream sediments have origins of mountain soil in natural and cattle manure in human activity. Nitrogen and carbon isotope analysis for mountain soil, cattle manure and stream sediment were performed for contribution evaluation of organic pollutants in Toil stream of Yeongju dam basin. Average carbon isotope ratio(δ¹³C) is -25.17‰, -22.34‰, and -26.39‰ for river sediments, cattle manure and mountain soil, respectively. Result of carbon isotope analysis suggests that river sediments are more affected by acid soils. Average value of the nitrogen isotope ratio (δ¹⁵N) is 9.46% for river sediment, 1.99% for mountain soil, and 19.53% for cattle manure. Result of nitrogen isotopic analysis show that contribution of cattle mature is slightly higher than that of mountain soil in Toil stream sediments.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.35-41
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• 1987

Nitrate nitrogen was absorbed dominantly among the inorganic nitrogen nutrients by tobacco plant. Transport and reduction of $NO_3-N$ in plant tissue were the important metabolism for supplying synthetic N compounds to developing tissues during growth period. Under field and environment-controlled condition tobacco plants were grown and seperated to leaf tissues at stalk positions for investigation of nitrogen transport and assimilation ability during period of rapid vegative growth. The results of studies were summarized as follows: 1. $NO_3-N$ absorbed from roots was transported as inorganic nitrogen through the vascular tissue of leaf veins as resulting from the high $NO_3-N$ ratio of the nitrogen content in leaf veins, but these ratios in mesophyll tissue of the same leaf laminae decreased remarkably in disregard of higher accumulation of nitrogen being compared to midvien. 2. Mesophyll tissue of mature leaves appeared higher value of nitrate reductase activity (NRA) comparing with other tissues, stem, leaf vien, and meristmatic tissue at emergence point with young leaves. 3. Matured leaves at lower position being reducing nitrate nitrogen vigorously observed thick laminae and kept high amount of water in them. 4. Mature leaves of young plant reduced $NO_3-N$ vigorously for supply synthetic N compounds to meristmatic tissues at growing point by the reason of narrow and few leaves at young stage, but in advancing growth period NRA of mature leaves along upper position reached to lower value. This appearence attributed to distribution of organic-N compound demanding for growth to increasing numbers of wide leaves.

• Journal of Korean Society of Forest Science
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• v.3 no.1
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• pp.36-42
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• 1963

The results obtained are summarized as follows: 1. In both years of 1960 and 1961, the flowering times, fading times of flowers, mature times of fruits of 63 chestnut varieties grown at Choosan area, Chon Nam, have been investigated. Almost the ages of trees were 26-year-old and they are growing on the brown forest soil well drained with relatively thick surface soil. 2. Non-significant difference in flowering time by the varieties has been found between the years. The carliests in floweing time are Toyotama-wase, The isho-wase, Asami-wase, Umehira-wase, i.e., bloomed on May, 22, or a little later. 3. The fading dates of flowers of each varieties almost linearly correlated to the flowering date. The blooming period of each varieties was about 10 to 12 days. 4. Linear correlation between mature time and blooming time are observed, i.e., the earlier the blooming time comes, the earlier is the mature time of chestnut fruit. 5. The varieties having the smallest sized seed, are Otomune and Boji-kuri, however, those having the large one, are Ho-gin, Katayama, Ohara-wase.

• Korean Journal of Organic Agriculture
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• v.22 no.3
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• pp.413-421
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• 2014

This study was conducted into the effects of cover crops among the hairy vetch, red clover, rye, and hairy vetch+rye on the soil chemical and physical properties, and fruit yield in mature 'Fuyu' persimmon (Diospyros${\times}$kaki Thunb.) trees. The shallow-rooted red clover had poor dry matter production, resulting in the lowest coverage (66%) on the orchard floor. In contrast, the highest dry matter production observed in rye and hairy vetch+rye. Estimated N, P and K production from the cover crops were the highest on the hairy vetch+rye plots, increasing soil chemicals at a depth of 0-30 cm soil. Rye or hairy vetch+rye treatments decreased the soil bulk density and solid phase. As the hairy vetch+rye treatment increased fruit yield and sugar contents, it could be proposed as an suitable cover crop for improving productivity of persimmon trees.