• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.135-141
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• 2007

Although the result of the tree height growth after water treatment, Fraxinus rhynchophylla has little affection by the artificial water treatment, the growth showed decreased tendency as the soil moisture decreased, and F. mandshurica showed high growth in relatively high soil moist $78{\sim}90%$ treated area. The growth of root collar diameter of F. rhynchophylla and F. mandshurica also showed decreased tendency as soil moisture decreased. The changes of biomass according to dry weight of root, stem, leaves of F. rhynchophylla demonstrating statistical significance as moisture contents of soil is lower showing decreased biomass tendency and in the treatment of $78{\sim}90%$(A) moisture content showed more than double the higher biomass compare to the treated area of $18{\sim}30%$(D) moisture contents. Also F. mandshurica showed statistical significance in A and D treatment demonstrating differences among each treatment. This can be purported to have physiological effects like weakening of seedling and softening of tissues including leaves as soil moisture decreased. Ultimately it is regarded to the main reason of unsatisfactory growth for F. rhynchophylla and F. mandshurica that are weak to drought resistance. SLA, which is one of the special traits of leaf area of F. rhynchophylla, didn't show statistical significance between moisture process, it demonstrated decreased tendency as the moisture content interval is minimal. LAR and LWR showed increased tendency while moisture content didn't show statistical significance between treatments as they are minimal.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.77-77
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• 2018

천마(Gastrodia elata)는 연중생산을 위해 실내시설 재배 시 생육모델을 구죽하고, 생육단계에 따른 온도, 수분, $CO_2$ 등 환경 조건 설정이 필요하다. 본 연구는 천마의 생육단계 중 괴경형성기와 괴경비대기의 수분함량을 설정하여 최적의 환경조건을 찾기 위해 수행하였다. 먼저 괴경형성기 수분함량 공급은 괴경형성기에 -20kPa, -30kPa, -40kPa로 처리하여 120일간 배양한 뒤, 괴경비대기를 -40kPa로 고정하여 60일간 배양하였다. 반면, 괴경비대기 수분함량 공급은 괴경형성기를 -30kPa로 고정하여 120일간 배양한 뒤 괴경비대기에 -20kPa, -30kPa, -40kPa, -50kPa로 처리하여 60일간 배양하였다. Tensiometer(토양수분장력계)기를 설치하여 수분을 공급하였고, FDR센서 (UbiMas, CoCo sensor, Frequency domain reflectometry type)를 배양토의 깊이 5 cm와 15 cm에 2개를 설치하여 평균값으로 수분함량을 측정하였으며, 전체수량, 성마율, 종마율 등을 조사하였다. FDR센서로 수분함량을 측정한 결과, -20 kPa은 43.3%, -30 kPa은 34.7%, -40 kPa은 29.8%, -50 kPa은 25.3%로 측정되었다. 괴경형성기 수분함량 처리 후 수확기의 상자 당 전체수량은 -30 kPa일 때 985 g으로 가장 많았고, -40 kPa일 때 912 g, -20 kPa일 때 703 g으로 처리간의 유의적인 차이를 보였다. 성마율은 수분함량처리별 각각 25, 34, 30% 이었고, 종마율은 수분함량처리별 각각 53, 73, 65%로 나타났다. 따라서 -30 kPa 처리구가 다른 처리구에 비해 전체수량, 성마율, 종마율 등이 유의적으로 우수하였다. 괴경비대기 수분 함량 처리 후 수확기의 상자 당 전체수량은 -40 kPa일 때 992 g으로 가장 많았고, -50 kPa일 때 955 g, -30 kPa일 때 903 g, -20 kPa일 때 686 g 순으로 나타났다. -30 kPa에서 -50 kPa 사이에서는 전체 수량의 유의성 차이는 없었다. 성마율은 수분함량처리별 각각 20, 30, 35, 33%이었고, 종마율은 수분함량처리별 각각 45, 65, 75, 68%로 나타났다. 따라서 -40 kPa 처리구가 다른 처리구에 비해 전체수량, 성마율, 종마율 등이 유의적으로 우수하였다. 반면 -20 kPa 처리구는 과도한 수분으로 천마가 오히려 부패될 수 있는 환경조건이 조성됨에 따라 성마율, 종마율 등 전체적인 수량 감소에 영향을 미친 것으로 판단되었다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.2
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• pp.267-273
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• 1996

열풍건조 전 전처리로서 $50^{\circ}C의$ 2%(w/v)가용성 전분용액에서 20분간 침지를 한 처리구와 건조 후 분말 입자크기가 $40^{\circ}C,$ 90%RH의 저장 중 분말양파의 물리적 성질에 미치는 영향을 조사하였다. 저장 중 수분흡수는 처리구와 대조구 모두 분말양파의 입자 크기에 관계없이 저장 초기에 빠르게 이루어진 후 저장시간이 지남에 따라서 둔화되었다. 처리구가 대조구에 비하여 저장중 수분흡수가 작게 나타났다. 처리구의 경우 분말입자가 큰 -24+60 mesh의 수분흡수는 저장 6시간 후 처리구와 대조구의 덩어리 형성 정도는 각각 12.26과 60.1%이었다. 입자 크기에 다른 덩어리 형성 정도는 처리구에서 저장 1시간 후 2.28%과 23.6%로 나타났다. 겉보기 밀도에서는 처리구가 대조구에 비하여 전반적으로 높은 값을 나타내었으며 처리구의 경우 수분흡수가 0.03에서 0.12g수분/g고형분으로 늘어남에 따라서 겉보기 밀도는 입자가 큰 분말은 0.49에서 0.38g/㎤이였으며 입자가 작은 분말은 0.31에서 0.29g/㎤로 나타났다. 압축성에서는 입자 크기가 크고, 수분흡수가 많이 이루어진 분말일수록 도한 대조구가 처리구 보다 응집성질을 가지게 되므로 높은 값을 나타내었다. 이완상수에서는 입자가 큰 처리구의 경우 수분흡수가 3.0과 12.1%이루어 진 것을 비교하면 각각 2.45와 2.01로 나타났다. 이는, 수분흡수가 높아짐에 따라서 고체 성질이 줄어들게 됨으로써 이완상수값이 낮아지기 때문이다.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.601-610
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• 1998

This study was carried out to investigate the possibility of supplemental UV-B application to the hardening phase of container-grown Betula platyphylla seedlings. The containerized seedlings were grown in a growth chamber for four months and then treated with UV-B(UV-$B_{BE}$ $3.2KJ\;m^{-2}\;day^{-1}$ and $5.2KJ\;m^{-2}\;day^{-1}$) radiation and water stress regime(irrigation in one week interval) for four weeks. The differences in growth and physiological responses of the seedlings before and after the treatments were analyzed. UV-B radiation and water stress reduced height growth and leaf dry mass accumulation of the seedlings. The root collar diameter growth was reduced by UV-B radiation but increased by water stress. The reduction in leaf dry weight by UV-B radiation and water stress reduced T/R ratio of the seedling. The reduction in T/R ratio was the most apparent by water stress. Chlorophyll index observed by a chlorophyll meter was the lowest in the $5.2KJ\;m^{-2}\;day^{-1}$ of UV-B radiation, and those in the $3.2KJ\;m^{-2}\;day^{-1}$ and water stress were similar. UV-B radiation and water stress reduced both water content in the seedlings and leaf water potential, and increased leaf osmatic pressure. The water content of leaves and shoots was reduced more rapidly by UV-B radiation than by water stress treatment. In conclusion, growth responses and physiological changes in water relation by supplemental UV-B radiation which was applied to the hardening phase of container-grown Betula platyphylla seedlings were similar results to the water stress treatment.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.507-507
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• 2022

작물 재배에서 정밀 관개 및 물관리를 위해 토양수분 모니터링이 필수적이며, 최근 이상기후에 따른 가뭄 빈도가 증가함에 따라 토양수분 변동에 따른 적절한 대응이 필요한 실정이다. 특히, 국산밀 생장기의 토양수분 및 관개는 생산성에 중요한 영향을 미치고 있으나, 빈번한 봄가뭄의 영향으로 작물 생산 및 품질 관리의 어려움을 겪고 있다. 따라서 국산밀의 안정적 생산을 위한 토양수분 및 양분 관리에 대한 연구가 필요하다. 본 연구에서는 ICT 기반의 토양 층위별 모니터링 시스템을 구축하여 물관리에 따른 국산밀의 안정적 생산성을 분석하고자 한다. 대상지역은 전라북도 남원시 운봉읍에 위치한 국립식량과학원 운봉시험지이며, 시험포장은 수분처리 조건에 따라 총 4개(A: 한발조건, B: 적정수분, C: 무처리) 처리구로 3개 블록을 구분하여 4반복으로 구성하였다. ICT 기반 10개 토양수분 및 EC (Electrical conductivity) 관측 장비를 통해 실시간으로 자료 수집하였으며, 밀 생육조사는 생육단계별 초장, LAI, 지상부 및 지중 생체중 등 자료를 수집하였다. 수집된 자료는 처리구별 물관리에 따른 토양수분과 생육지표의 상관관계 분석을 통해 가뭄에 따른 생육 영향과 적정 관개용수의 공급시기 및 공급량을 분석하였다. 본 연구는 밀 생장기의 봄가뭄에 대응하기 위한 물관리 기초자료로 활용하고자 하며, ICT 기반의 스마트관리 플랫폼을 개발하여 밀 작황 진단 및 예측을 통해 국산밀의 안정적 생산성에 기여하고자 한다.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.3
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• pp.173-179
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• 1990

The effect of a highly water absorbing polyacrylate polymer, commonly called K-sorb, at rates of 0.0, 0.05, 0.2, and 0.5% by weight on the water retention properties of three soils, and the longevities of these treatment effects were evaluated. Water retentions were measured for all the treatments by use of a pressure-plate extractor in the laboratory. Available water and three-phase distributions at moisture tensions of 0.01, 0.3, and 15b were calculated from water retentivity data. A randomized block experiment of Chinese cabbages was conducted to examine the effects and the longevities of the treatments(0.0, 0.05, 0.1, and 0.2%) on water retention of Jungdong sandy loam soil in the field. Water retentions for a loamy sand, sandy loam, and loam soil, treated with 0.2 and 0.5% K-sorb, were increased. K-sorb treatments were more effective in sandy soil than in loamy soils. Water contents for the 0.5% treatment were markedly greater than those for the 0.2% treatment at earth moisture tension. K-sorb only at a rate of 0.5% remained effective in water retention of each soil through repeated drying and wetting for 12 months. Duncan's multiple range showed 0.2% treatment was effective(at the level of 0.05) after 2 months but not after 10 months under field condition.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.4
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• pp.47-53
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• 1999

In order to elucidate physiological factors involved in causing the winter injuries of evergreen Japanese rhododendron (Rhododendron obtusum cv. Hinodegiri) and semi-evergreen rhododendron (Rhododendron yedoense var. poukhanense), these studies were conducted from late winter to early spring. The results were summarized as follows; The water potential, water content in stem, water potential and content have continuously increased in both species between February and May. In R. yedoense, shading treatment had 0.3MPa upper water potential and 3% upper water content than the control. Rhododendron obtusum, the treatments with shading had 0.9MPa upper water potential and 11% upper water content that the control. The difference of water balance by treatments could be found in vitality of stem measured by TTC test. Especially R. obtusum in the treatments with shading in has higher vitality than the control. we find that winter damage of evergreen R. obtusum was determined by whether water balance could be recovered from water deficient state during the dehardening period, or not. In order to recover of the water balance, decreasing water loss more important than increasing water supply, and that was effectively acrueved by the treatment with shading.

• Korean Journal of Plant Resources
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• v.20 no.4
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• pp.267-271
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• 2007

This study was carried out to examine optimal hot water treatment time in Albizzia julibrissin seeds. Germination and moisture absorption characteristics among intact seeds, immersed seeds for 24 hours in distilled water and hot water treated seeds were surveyed. As result, treated seeds showed a highly significant difference with intact and immersed seeds (p<0.0l). Especially, treated seed for 2.0 minutes represented the highest percent of germination (PG). But mean germination time (MGT) did not have significant difference between non-treatment and treatments (p=0.502). Germination speed and germination performance index showed similar tendency with PG. In percent of moisture absorption (PMA) and moisture absorption rate constant (MARC) treatments had higher values than non-treatment whereas 2.0 minutes treatment was lower than non-treatment in initial moisture absorption rate (IMAR). In relation between germination properties and moisture absorption characteristics, all properties except MGT among germination properties had high correlations with PMA and MARC ($r=0.854{\sim}0.931$,p<0.01) whereas IMAR didn't have correlation.

• Korean Journal of Medicinal Crop Science
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• v.5 no.1
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• pp.1-6
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• 1997

The experiment was conducted to investigate the effect of water stress on yield and quality of Ligusticum chuanxiong Hort. The water stress treatment was imposed artificially on seedling, flowering and rhizome enlargement stage of the plant. The root yield rate decreased to 19.1%, 18.2% and by the water stress treatment at rhizome enlargement, seedling and flowering stage, respectively. Portion of the products having commercial quality grade (above 20g of rhizome weight) was 93.4% at control plot, while it was 85%, 81.7% and 78.3% when stressed for water at seedling, flowering and root enlargement stage, respectively. Content of extract was the higher in the order of control, water stressed at rhizome enlargement, flowering and the seedling stage. Postive correlationship was found between yield of rhizome and rootlet yield or economic production ratio, and between dry weight of stem and rootlet yield.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.266-274
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• 2010

This study aim to investigate fundamentally the growth and physiological responses of tomato plants in responses to two different levels of water deficit, a weak drought stress (-25 kPa) and a severe drought stress (-100 kPa) in soil. The two levels of water deficit were maintained using a micro-irrigation system consisted of soil sensors for the real-time monitoring of soil water content and irrigation modules in a greenhouse experiment. Soil water contents were fluctuated throughout the 30 days treatment period but differed between the two treatments with the average -47 kPa in -25 kPa set treatment and the -119 kPa in -100 kPa set treatment. There were significant differences in plant height between the two different soil water statuses in plant height without differences of the number of nodes. The plants grown in the severe water-deficit treatment had greater accumulation of biomass than the plants in the weak water-deficit treatment. The severe water-deficit treatment (-119 kPa) also induced greater leaf area and leaf dry weight of the plants than the weak water-deficit treatment did, even though there was no difference in leaf area per unit dry weight. These results of growth parameters tested in this study indicate that the severe drought could cause an adaptation of tomato plants to the drought stress with the enhancement of biomass and leaf expansion without changes of leaf thickness. Greater relative water content of leaves and lower osmotic potential of sap expressed from turgid leaves were recorded in the severe water deficit treatment than in the weak water deficit treatment. This finding also postulated physiological adaptation to be better water status under drought stress. The drought imposition affected significantly on photosynthesis, water use efficiency and stomatal conductance of tomato plants. The severe water-deficit treatment increased PSII activities and water use efficiency, but decreased stomatal conductance than the weak water-deficit treatment. However, there were no differences between the two treatments in total photosynthetic capacity. Finally, there were no differences in the number and biomass of fruits. These results suggested that tomato plants have an ability to make adaptation to water deficit conditions through changes in leaf morphology, osmotic potentials, and water use efficiency as well as PSII activity. These adaptation responses should be considered in the screening of drought tolerance of tomato plants.