• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.244-249
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• 1999

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.136.1-136
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• 1994

• Proceedings of the Plant Resources Society of Korea Conference
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• 1997.10b
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• pp.27-28
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• 1997

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.41-41
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• 2017

본 연구는 초분광 영상을 이용하여 수박 모종의 수분함량을 비파괴적으로 추정하기 위해 수행되었다. 단계적으로 수분 스트레스를 받은 수박(n=45) 모종을 초분광 영상시스템으로 촬영하여 모종 영역의 반사율을 추출하였고, 매 촬영 후 모종의 생체중과 건물중을 측정하여 수분함량을 계산하였다. 모종의 반사율과 계측된 수분함량을 변수로 하여 Partial Least Square Regression(PLSR) 분석을 이용하여 수분 추정 모델을 구축하였다. 수분 추정모델을 작성한 결과 Calibration(Cal.)의 정확도($R^2$)는 0.66, 정밀도(RMSE 및 RE)는 각각 1.06%, 1.14%로 나타났다. 수박 모종의 수분함량 추정모델의 정밀도는 상당히 높게 나타났으나 정확도는 낮게 나타났다. 정확도를 개선하기 위해 Confidence ellipses의 신뢰구간을 95%로 설정하였을 때 3개의 모종이 타원 밖에 위치하는 것을 발견하였으며 이를 제거 후 재분석을 하였다. 3개의 모종을 제외한 수박 모종의 수분함량 추정모델의 정확도는 0.82, 정밀도는 0.73%, 0.78%로 나타났다. 3개의 모종을 제외함으로서 모델의 정확도 및 정밀도가 상승하여 3개의 모종이 정확도 및 정밀도를 낮추는 원인이라 판단된다. 작물은 가뭄스트레스를 받을수록 반사율이 낮아지지만(Yang et al., 2010) 3개의 모종은 다른 모종의 수분함량에 비해 반사율이 큰 차이를 나타내어 정확도 및 정밀도를 낮춘 것으로 판단된다. 본 연구를 통해 초분광 영상을 이용하여 수박 모종의 수분함량 추정가능성을 시사하였고, 모델의 정확도를 개선하기 위해 샘플 수 및 수분함량의 변이를 증가시키는 것이 필요하다고 판단된다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.296-302
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• 2005

We investigated changes in photosynthetic characteristics of P. davidiana in order to understand damage patterns to photosynthetic apparatus under drought stress. Root sprout saplings of P. davildiana were treated with $0\%,\;2\%,\;5\%,\;and\;10\%$ of 300ml polyethylene glycol (PEG) once a weer far one month. After one month, we measured photosynthetic parameters and analyzed the photochemical and $CO_2$ fixation systems. Photosynthetic rate, stomatal conductance, and respiration rate in the leaves of P. davildiana decreased according to increasing stress strength. In the photochemical system, quantum yield of PSII was reduced by the increment of PEG concentration, The decrease of apparent quantum yield was related to reduction of electron transport. Respiration rate decreased with an increase in PEG concentration, whereas photorespiration rate in the $CO_2$ fixation system increased. In conclusion, photosynthesis of P. davidiana responded sensitively under drought stress, and the sensitivity depended upon the strength of water stress. P. davidiana exhibited an increase of water use efficiency under water stress.

• Korean Journal of Environment and Ecology
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• v.27 no.6
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• pp.745-756
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• 2013

This study was carried out to suggest an experimental base to maintain the sustainability of extensive green roof as considering moisture demand by the type of the green roof plant before construction. The changes of soil moisture content, chlorophyll content, coverage of Sedum kamtschaticum and Dianthus chinensis var. senperflorens in two type of perlite soil and mix soil, were investigated under the condition of no rainfall and no irrigation during one month. The result shows that with the increase of stress time, soil moisture content and chlorophyll content on leaf were in a downward trend; After 30 days, Soil moisture content were lowest in 10 cm depth perlite soil system planted Dianthus chinensis. and 20 cm depth mix soil system planted Sedum kamtschaticum had the highest soil moisture. Generally soil moisture contents of soil system planted Dianthus chinensis var. senperflorens were lower than that of soil system planted Sedum kamtschaticum. In 10 cm depth soil system, state of plant growth was better than 20 cm depth soil system both perlite soil and mix soil type. It can be confirmed.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.213-221
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• 2006

This study was designed to determine what sensor-based technologies might reliably and accurately predict irrigation scheduling needs of warm-season turfgrass. 'Floratam' St. Augustinegrass[Stenotaphrum secundatum(Walt.) Kuntze] and 'Sea Isle I' seashore paspalum(Paspalum vaginatum Swartz) were established in tubs in the Envirotron Turfgrass Research Laboratory in Gainesville, FL in the spring of 2002. Each grass was subjected to repeated dry-down cycles where irrigation was withheld. Sensor-based data were collected and these evaluations were used to determine if irrigation scheduling could be determined based on plant response during dry-down. Results indicated that reflectance indices($P{\le}0.001$) and soil moisture($P{\le}0.0001$) throughout the dry-down cycle can predict the need for irrigation scheduling as turf quality declined below acceptable levels.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2019.10a
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• pp.181-181
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• 2019

• The Korean Journal of Ecology
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• v.17 no.3
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• pp.241-249
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• 1994

Leaf diffusive resistance (LDR), stomatal density, length of guard cell and hair density of leaves of 6 oak species were determined under withdrawal of water, and their strategies of drought stress were analyzed by principal component analysis. LDR of Quercus acutissima, Q. aliena and Q. serrata increased earlier than those of the other species at high leaf water potential $({\Psi}_{leaf})$ or low water saturation deficit (WSD), which was an avoidance mechanism reducing damage by water stress. Q. variabilis with low stomatal density, small stomatal size and high hair density had avoidance mechanisms increasing LDR at high $({\Psi}_{leaf})$ However, Q. mongolica and Q. dentata increased LDR at low $({\Psi}_{leaf})$ as xeric species do. Results from principal component analysis on the 15 variables related to strategies of drought stress indicated that the 6 oak species were divided into 2 groups: (1) Q. acutissima, Q. aliena and Q. serrata as mesic habitat species and (2) Q. variabilis, Q. mongolica and Q. dentata as xeric habitat species. Among three xeric species Q. acutissima differed from the other two species in the drought strategies such as high hair density, low stornatal density, high leaf area ratio, stomatal closing at low $({\Psi}_{leaf})$ and small cell wall elasticity. The results could reasonably explain their drought strategies in natural habitat.

• Ecology and Resilient Infrastructure
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• v.10 no.3
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• pp.64-72
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• 2023

Biopolymer is a versatile material used in food processing, medicine, construction, and soil reinforcement. 𝛽-glucan is one of the biopolymers that improves the soil water content and ion adsorption in a drought or toxic metal contaminated land for plant survival. We analyzed drought stress damage reduction in sweet potatoes (Ipomoea batatas L. cv. Sodammi) by measuring the growth and major protein expression and activity under 𝛽-glucan soil amendment. The result showed that sweet potato leaf length and width were not affected by drought stress for 14 days, but sweet potatoes grown in 𝛽-glucan-amended soil showed an effect in preventing wilting caused by drought in phenotypic changes. Under drought stress, sweet potato leaves did not show any changes in electrolyte leakage, but the relative water content was higher in sweet potatoes grown in 𝛽-glucan-amended soil than in normal soil. 𝛽-glucan soil amendment increased the expression of plasma membrane (PM) H⁺-ATPase, but it decreased the aquaporin PIP2 (plasma membrane intrinsic protein 2) in sweet potatoes under drought stress. Moreover, water maintenance affected the PM H⁺-ATPase activity, which contributed to tolerance under drought stress. These results indicate that 𝛽-glucan soil amendment improves the soil water content during drought and affects the water supply in sweet potatoes. Consequently, 𝛽-glucan is a potential material for maintaining soil water contents, and analysis of the major PM proteins is one of the indicators for evaluating the biopolymer effect on plant survival under drought stress.