• The Korean Journal of Ecology
• /
• 제8권2호
• /
• pp.61-68
• /
• 1985

The modeling of interception and absorption of light was studied in plant canopies at Mt. Kwanak. Followering results were obtained. Light intensity passing through the stacked leaves is attenuated exponentially. This phenomenon seems to be more clearly applied to the plant canopies, if they have large cumulative leaf area and are matured densely. Light interception and absorption are influenced by leaf thickness, shape pigments, and leaf area, and they have great effect on the maturation of canopies. It was confirmed that the light penetrating through the stratified canopies is decreased exponentially in dual pattern. The cumulative leaf area of a definite space in a certain plant canopy is the same as the growth of leaf area of the canopy at that time. A hypothetical model for calculating the light absorption in plant canopies, was established on the bases of phenomena that incident light is captured at the maximum level and light inerception effect is minimized by leaves.

• 생물환경조절학회지
• /
• 제28권4호
• /
• pp.279-285
• /
• 2019

작물의 일중 광합성량을 정확하게 추정하기 위해서는 일중 태양의 위치 변화에 따른 작물의 정확한 수광량 변화를 정확하게 예측해야 한다. 그러나, 이는 많은 시간, 비용, 노력이 소요되며, 측정의 어려움이 수반된다. 현재까지 다양한 모델링 기법이 적용되었으나 기존 방식으로는 정확한 수광 예측이 어려웠다. 본 연구의 목적은 파프리카의 3차원 스캔 모델과 광학 시뮬레이션을 이용하여 일중 시간 별 캐노피 수광 분포와 광합성 속도의 변화를 예측하는 것이다. 휴대용 3차원 스캐너를 이용하여 온실에서 재배되는 파프리카의 구조 모델을 구축하였다. 주변 개체의 유무에 따른 캐노피 수광 분포의 변화를 보기 위하여 작물 모델 별 간격을 60cm로 $1{\times}1$, $9{\times}9$ 정방형 배치하여 광학 시뮬레이션을 수행하였다. 광합성 속도는 직각쌍곡선 모델을 이용하여 계산하였다. 3차원 파프리카 모델 표면의 수광 분포는 오전 9시, 정오, 오후 3시의 태양 각도에 따라 서로 다른 양상을 보였다. 캐노피 총 수광량은 $9{\times}9$ 배치로 주변 개체 수가 늘어남에 따라 감소하였고, 태양 고도가 가장 높은 정오에서의 감소율이 가장 적었다. 캐노피 광합성 속도와 $CO_2$ 소모량 역시 수광량과 비슷한 양상을 보였으나 작물 상단부 엽의 광합성 속도 포화로 인해 수광량 변화에 비해 적은 감소율을 보였다. 본 연구에서는 파프리카의 3차원 스캔 모델과 광학 시뮬레이션을 이용하여 가상 환경 조건에서의 캐노피 수광과 광합성 분포를 분석할 수 있었으며, 이는 추후 다양한 재배 조건에서 작물 수광량과 광합성 속도를 예측하는 데에 효과적으로 활용될 수 있을 것으로 사료된다.

• 한국자원식물학회지
• /
• 제8권3호
• /
• pp.265-274
• /
• 1995

유자(Citrus junos)에 있어서 수관내 위치별 엽, 엽면적, 엽중의 특성차이와 정아의 발생상태, 화아분화와 과실 품질에 미치는 기초자료들을 얻고져 실험을 실시하였던 바 결과는 다음과 같다. 1. 동, 서, 남, 북의 방향별 엽수, 엽면적, 엽중에 있어서는 유의차가 없었다. 2. 수관의 상하간에는 엽수와 엽면적은 유의차가 었었다. 3. 정아의 횡경과 종경은 방향별로는 차이가 없었지만, 상하간에는 유의한 차이를 나타내었다. 4. 투과광도와 엽 및 엽면적과의 상관관계는 광도 감소율에 따라 엽의 엽비중이 가장 큰 영향을 받았으며, 단과지당 전체엽중, 평균 엽중, 단과지 정아의 횡경, 종경도 높은 상과관계를 나타내었다. 5. 화아분화에 차광은 비효과적이었으며, GA처리도 같은 경향을 나타내었다. 6. 적과는 1과당엽수를 40잎 이상으로 하는 것이 화아분화율과 과실의 품질을 향상시킬 수 있었다.

• 한국자원식물학회지
• /
• 제32권6호
• /
• pp.677-682
• /
• 2019

Hand leaf thinning for improvement of fruit coloration and quality is one of the most labor-consuming works in Korean apple cultivation. The study was aimed at investigating whether foliar application of two chelate compounds (Cu-EDTA, Fe-EDTA) could defoliate effectively 'Hongro'/M.9 apple leaves and enhance fruit coloration and quality. At 30 days before harvest, foliar spray with two chelate compounds defoliated significantly the apple leaves. Chelate treatments did not affect the leaf chlorophyll content. High concentration of chelates decreased drastically photosynthetic rate of true leaves, and then it stayed in low levels, whereas low levels of chelates reduced sharply the photosynthetic rate but it was gradually restored over time. Cu-EDTA regardless of its concentration triggered higher defoliation compared to Fe-EDTA. Consequently, higher defoliation improved light interception of fruits and accumulated more anthocyanin. Particularly, Cu-EDTA could target mainly fruit cluster leaves which affect directly light interception of the fruits, i.e. more selective defoliants compared to Fe-EDTA. However, 3% Cu-EDTA rather defoliated excessively, accompanying with reduction of fruit weight and soluble solids. Therefore, our results suggest that 1% Cu-EDTA which defoliates properly the fruit cluster leaves could improve coloration and quality of 'Hongro'/M.9 apple fruits.

• Journal of Ginseng Research
• /
• 제34권3호
• /
• pp.175-182
• /
• 2010

North American ginseng seedlings (Panax quinquefolius L.) were grown in pots in heated greenhouses, in a cool greenhouse, or in the field, in 11 experiments at various times over 16 years. Crop establishment, dry matter partitioning, photosynthesis, radiation use efficiency and carbon budget were measured and/or calculated in some years. Once the seedling canopy, of about $20\;cm^2$ per seedling, and a leaf area index of 0.37, was established, about 40 days after germination, full canopy display lasted about 87 days. Only 16.6% of the incoming solar radiation was intercepted by the crop, the remainder falling on the mulched soil surface. Total and root dry matter accumulations in the cool greenhouse and in the field were about double that in the heated greenhouses. Partitioning of dry matter to roots (economic yield or harvest index) in the cool greenhouse and in the field was 73% whereas it was 62.5% in the heated greenhouses. The relationship between root dry matter and radiation interception during the full canopy period was linear with growth efficiencies of $2.92\;mg\;MJ^{-1}$ at 4.8% of incoming radiation and $0.30\;mg\;MJ^{-1}$ at 68% of incoming radiation. A photosynthetic rate of $0.39\;g\;m^{-2}\;h^{-1}$ was attained at light saturation of about $150\;{\mu}mol\;m^{-2}\;s^{-1}$ (7.5% of full sunlight); dark respiration was $0.03\;g\;m^{-2}\;h^{-1}$, about 8.5% of maximum assimilation rate. Estimates of dry matter accumulation by growth analysis and by $CO_2$ uptake were similar, 6.21 vs. 7.62 mg $CO_2$, despite several assumptions in $CO_2$ uptake calculations.

• 생물환경조절학회지
• /
• 제28권1호
• /
• pp.86-93
• /
• 2019

식물의 생육과 형태는 광 환경에 영향을 받는다. 식물공장에서 재배되는 작물의 형태형성과 생육은 태양광과 다른 양상을 보이며 이는 태양광에 존재하는 원적색광 영역에 의한 영향으로 유추된다. 본 연구의 목적은 태양광 파장 유사 조합광(AS), 고압나트륨등(HPS) 및 원적색광을 추가한 고압나트륨등(HPS+FR)에서 재배된 오이의 형태형성과 생육을 비교하는 것이다. AS는 황 플라즈마 광원과 백열등, 녹색 광 차단 필름을 이용하여 제작하였다. 인공광원은 HPS를 이용하였고, 여기에 원적색광 LED를 추가하여 각 광원의 특성 및 식물의 형태형성, 생육 및 광합성 속도를 비교하였다. R/FR 값과 PSS는 AS와 HPS+FR이 유사하였다. 식물의 형태와 생육은 HPS와 HPS+FR 간에는 유의한 차이가 있었지만 AS와 HPS+FR간에는 유의한 차이가 없었다. SPAD는 HPS에서 높았으며 광합성속도는 AS와 HPS에서 높았다. HPS+FR의 광합성 속도는 HPS에 비해 낮았지만 원적색광에 의한 엽면적과 엽병 길이 증가로 인해 수광 면적이 증가하였고, 결과적으로 AS와 유사한 생육이 나타난 것으로 판단되었다. 인공광원에 원적색광을 추가하였을 때 태양광 하에서와 유사한 광형태형성 및 생육이 나타나는 것을 확인하였다. 이러한 결과로부터 식물공장에서 기존의 인공광원에 원적색광을 추가하면 동일한 효과를 얻을 수 있을 것으로 기대한다.

• Horticulture, Environment, and Biotechnology : HEB
• /
• 제59권6호
• /
• pp.827-833
• /
• 2018

Plasma lighting systems have been engineered to simulate sunlight. The objective of this study was to determine the effects of plasma lighting on tomato plant growth, photosynthetic characteristics, flowering rate, and physiological disorders. Tomato plants were grown in growth chambers at air temperatures of $25/23^{\circ}C$ (light/dark period), in a $16h\;day^{-1}$ light period provided by four different light sources: 1 kW and 700 W sulfur plasma lights (1 SPL and 0.7 SPL), 1 kW indium bromide plasma light, and 700 W high pressure sodium lamp (0.7 HPS) as a control. The totaldry weight and leaf area at 0.7 SPL were approximately 1.2 and 1.3 times greater, respectively, than that of 0.7 HPS at the 62 days after sowing (DAS). The maximum light assimilation rate was observed at 1 SPL at the 73 DAS. In addition, the light compensation and saturation points of the plants treated with plasma lighting were 98.5% higher compared with HPS. Those differences appeared to be related to more efficient light interception, provided by the SPL spectrum. The percentage of flowering at 0.7 SPL was 30.5%, which was higher than that at 0.7 HPS; however, there were some instances of severe blossom end rot. Results indicate that plasma lighting promotes tomato growth, flowering, and photosynthesis. Therefore, a plasma lighting system may be a valuable supplemental light source in a greenhouse or plant factory.

• 생물환경조절학회지
• /
• 제32권1호
• /
• pp.1-7
• /
• 2023

시설 내 작물이 이용하는 수광특성의 이해와 지속적으로 변화하는 광환경의 추적은 광합성과 증산반응 연구에서 중요하다. 또한 재배기간 동안 작물이 생장함에 따라 광이용 형태가 지속적으로 변화한다. 따라서 본 연구에서는 작물의 생육을 반영한 흡광계수 추정 모델을 개발하였다. 흡광계수의 측정을 위하여 작물의 높이에 따라 수직으로 일사량계를 5개 설치하였으며, 작물의 전 생육기간(1-85DAT) 동안 1초 단위로 측정을 하였다. 초기, 중기, 후기 각각의 생육단계에 따라 최상단 광량과 최하단의 광량의 차이가 69%, 72%, 81%로 증가하는 경향을 보였다. LAI와 초장이 증가함에 따라 흡광계수는 감소하였으며, 지수적 감소 관계를 보였다. 두 생육지표를 모두 반영한 3차원 모델에서는 Paraboloid 식이 평균 제곱근 오차(RMSE)가 1.340으로 가장 낮았고, 결정계수(R²)는 0.968로 가장 높았다. 본 연구를 통하여 작물 재배기간 동안 보다 정확한 흡광계수를 예측할 수 있게 되었고, 이는 작물의 높이에 따른 광합성 및 증산량 예측과 분석 연구에 활용될 수 있을 것으로 판단된다.

• Journal of Ginseng Research
• /
• 제7권2호
• /
• pp.172-192
• /
• 1983

Light environment and growth of Panax ginseng In habitat and cultivation under natural shade were renewed. Grower's experiences on ginseng stand In relation to light environment were assessed. Change of shading method and grower's concepts on light requirement of ginseng plant in Korea, Manchuria and Japan was counted. Growth of wild ginseng was better under rich light. Optimum crown density index appeared to be 0.7 In natural habitat and 0.4 to 0.7 for the cultivation in forest. Change of light Intensity in forest was greatest in May and reached near to constant value (from 40% to 3% for broad leaf deciduous forest and loom 4% to 2% for pine forest). Insufficient light condition induced long and thin stem, poor flowering and seed bearing, and sequent dormancy. Relation between light and ginseng strand was not clear but light Interception with cool weather was effective. Topography and orientation of bed have been deeply considered for light environment. Panel or bark of won were used for shading in deep forest manly In Manchuria while reed blind and straw thatch were used in Korea. Kinds and number of shades material and seasonal or daily schedule have been simplified probably by labor pressure due to eulargement of plantation. Post height has been greater while width of roof, bed and ditch has changed lisle. Scientific survey in the past omitted important light control methods (complete light hardening etc) which has been practiced in specific areas. The concept and technique of light control in the past in Korea were delicate and intensive including the control of temperature and moisture. For the application of old concept in modem cultivation precise Investigation of the technique including the measurement of light, temperature and moisture is needed.

• 생약학회지
• /
• 제18권3호
• /
• pp.196-201
• /
• 1987

A study was carried out to investigate the possibility of acclimation of Coptis japonica Makino in Korea. Coptis japonica could be grown within 4 years as a medicinal crude drug if it is cultivated in the area of mountain facing north(300m above sea level) with 70% light interception and appropriate soil texture. It is to be noted that the propagation of the plant is more important than the yield of berberine because the berberine contents do not change in different conditions. The results were as follows; 1. The germination rates of the seeds by covering with the pine tree leaves were the highest and averaged 63%. 2. The germination rates of dry seeds were not affected in spite of low temperature and $GA_3$ treatment. 3. The germination rates of the seeds stored in moistured sand were averaged 85%, but in dry state, they were not germinated. 4. The number of leaves and fresh weight of Coptis japonica from the area of mountain facing north were increased significantly. 5. The growth and fresh weight of Coptis japonica were reduced in clay. 6. The best growth was obtained under 70% light interception. It is possible to intercrop between evergreen trees. 7. The foliage dressing did not affect the growth. 8. The number of leaves and fresh weight were increased from the 3rd year, and the average weight of rhizomes was 5.7g in 4th year. 9. The berberine contents of the rhizomes of Coptis japonica under various treatment conditions ranged from 9 to 10%. Coptidis Rhizoma from this study and from Korean market showed much higher berberine contents than those from Japanese market.