• Journal of Korean Society of Forest Science
• /
• v.99 no.1
• /
• pp.68-74
• /
• 2010

The present study was conducted to investigate growth performance and ascorbic acid contents of Allium victorialis var. platyphyllum, Ligularia fischeri, and L. stenocephala growing under four different light intensity regimes (full sun, and 64~73%, 35~42%, 9~16% of full sun). The leaf area and total biomass of Allium victorialis var. platyphyllum were highest in 35~42% of the full sun. However, the leaf area and total biomass were highest in 64~73% of the full sun in Ligularia fischeri, and L. stenocephala. The leaf thickness decreased with increasing shading in all three wild vegetables. The growth of root comparing to that of shoot decreased as shading increased, and as the result, the ratio of shoot biomass to root biomass increased. Ascorbic acid contents were higher in Allium victorialis var. platyphyllum than in Ligularia fischeri and L. stenocephala. Allium victorialis var. platyphyllum showed the highest contents of ascorbic acid in 35~42% of full sun. Whereas Ligularia fischeri and L. stenocephala showed the highest in 64~73% of full sun.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.10 no.4
• /
• pp.149-157
• /
• 2008

We investigated chlorophyll contents and growth performances of five deciduous hardwood species growing in central temperate zone of Korean forest. Cornus controversa, Fraxinus rhynchophylla, Betula schmidtii, Prunus leveilleana, and Acer mono seedlings were grown under four different light intensity regime (full sunlight, $65{\sim}72%$, $29{\sim}40%$, and, $7{\sim}12%$ of the full sunlight) for the experiment. The chlorophyll contents of all of the species were highest in $7{\sim}12%$ of the full sunlight, while lowest under the full sunlight. The relative growth rate of root collar diameter and height were decreased with increasing shading level except for Acer mono that showed the highest relative growth rate under $29{\sim}40%$ of the full sunlight. Total biomass and root volumes of the seedlings studied decreased as the light intensity decreased with different shade levels. For Acer mono, however, the biomass and root volumes were highest in $29{\sim}40%$ of the full sunlight. The relative growth rate of root comparing to shoot decreased as shading increased, and as a result, the ratio of aboveground to belowground biomass increased. As the shading level increased, specific leaf area (SLA), leaf area ratio (LAR), and leaf weight ratio (LWR) of most species increased.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.24 no.1
• /
• pp.11-24
• /
• 1979

To characterize elastic and plastic chilling injury, rice seedlings grown at 28/$16^{\circ}C$ day/night temp. under 20K lux (13hrs.) in a phytotron were subjected to a 11/$6^{\circ}C$, 20K lux condition for 2, 4, 6 or 8 days at 1, 2, 3, 4 or 5th leaf-stage, respectively, followed by further growth under 28/$16^{\circ}C$condition till 30th day after seeding. Japonica variety Jinheung and Chulwon No.1 survived almost 100% without any significant , discoloration and death of leaves due to chilling even under the chilling of 8 days at all seedling ages tested. Tongil and Yushin, varieties from Indica x Japonica cross, showed increasing discoloration of leaves and death of plants with increase in chilling intensity. The longest chilling duration shown seedling death less than 5% was 4, 6, 1, 4, 8 days for Tongil, and 6, 6, 1, 2, 2, days for Yushin at 1, 2, 3, 5th leaf-stage, respectively. The degree of discoloration and death of leaves or suppression of height growth was not explicitly related to seedling death or the dry weight reduction. The degree of seedling death or dry weight reduction could differentiate chilling tolerance of varieties and seedling ages, but somewhat differently. Reduction in dry weight due to chilling occurred even without any visible injury or seedling death. These suggest that both the degree of seedling death and reduction in dry weight should be considered in the test of varieties for chilling tolerance. Combined evaluation of seedling death and dry weight reduction indicated the most susceptible seedling age to chilling injury to be 1 to 2nd leaf-stage for Jinheung, 2 to 3rd leaf-stage for Chulwon No.1, 3rd leaf- stage for Tongil and Yushin, respectively.

• Korean Journal of Weed Science
• /
• v.6 no.2
• /
• pp.110-123
• /
• 1986

To know the ecological pattern of bulrush (Scirpus juncoides Roxb.) seeds and overwintreed stumps in germination and sprouting responses as affected by different temperature (7 trt.), light intensity (5 trt.), shading intensity (S trt.), light quality (specturm spectrum; 6 trt.), soil acidity (7 trt.), stump sizea (weight base; 5 trt.), and molding depth (6trt.), respectively, this serial studies were conducted by use of growth chamber, incubator, Wagner pot and petri-dish. Most efficient treatment was obtained from 25-$35^{\circ}C$ temperature, higher light intensity in 2-11 klux range, 95% shading intensity, clear and yellow film for seeds/clear and blue film for stumps, soil pH 5.53, 3-4g stump weight, 0-5% wxygen concentration, 1 ㎝ flooding depth for seeds, and 1-1.5cm molding depth for seeds/0.5-1.0 cm molding depth for stumps, respectively, among others.

• Journal of Korean Society of Forest Science
• /
• v.89 no.5
• /
• pp.591-597
• /
• 2000

This studies were carried out to investigate the optimum shading for seedling cultivation of Cornus controversa and C. walteri. The experiment was performed under five different shading scheme such as 100%, 50%, 30%, 10%, and 2% of the natural full sun light intensity for 7 months in the field condition. Two species showed the highest height growth under 50% of relative light intensity, and the highest diameter growth at root collar was observed both under 100% and 50% of relative light intensity. C. controversa seedlings grown under 50% of relative light intensity produced more total biomass than control seedlings, but root biomass was less in the seedlings under 50% of relative light intensity. In case of C. walteri, total biomass production of the seedlings under 50% of relative light intensity was lower than that of the seedlings under full sun light intensity, but leaves and shoot biomass was slightly high under 50% of relative light intensity. Great reductions of height growth and diameter growth at root collar, and biomass production were observed below 30% of relative light intensity in the both species. T/R ratio of the two species was highest under 30% of relative light intensity, and the chlorophyll content of the seedlings tended to be increased by reduction of relative light intensity.

• Journal of Bio-Environment Control
• /
• v.17 no.2
• /
• pp.132-137
• /
• 2008

This experiment was conducted to investigate the effect of supplemental lighting of low light intensities on growth and yield of rose 'Vital' in a forcing culture. Metal halide lamp (MH), High pressure sodium lamp (HSP), and MH+HSP were used as the light sources, and they were set up at a $310\;cm{\times}450\;cm$ interval and at 120cm above the culture beds. Light intensity at 1m point distance from supplemental lighting sources was $32{\sim}34\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Days to the 1st and 2nd harvests decreased by $5{\sim}8$ and $3{\sim}5$days, respectively in supplemental lighting treatment as compared to the control. Days to harvesting was the shortest in MH+HPS treatment, followed by BPS and MH, although there was no significant difference between HPS and MH treatments. The growth was better and incidence of blind shooting decreased by $5{\sim}7%$ in supplemental lighting treatments than the control, increasing marketable cut flowers. The incidence of blind shoot was the lowest in MH+BPS treatment, and there were no significant difference between MH and BPS treatments. In conclusion, supplemental lighting of low light intensities was effective in reducing days to flowering and reduced occurrence of blind shoots.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.28 no.3
• /
• pp.363-368
• /
• 2001

It is well known that numerous factors influence the light output of curing units, but many dentists are un aware that the output of their curing lights are inadequate. This study was conducted to evaluate the light in tensity of visible-light curing units in some private dental clinics and hospital dental clinics. In order to determine the maximum light intensity of the curing units, lamps, filters and fiber optic bundles, they were replaced with new ones and light intensity was remeasured. Light intensity was measured by employing a digital radiometer (EFOS model #8000, USA). Light intensity ranged in $29\sim866mW/cm^2$ (below $150mW/cm^2$ ; 17.8%, $150\sim300mW/cm^2$ : 46.6%, above $300mW/cm^2$ ; 35.6%). The replacement of the components increased the light intensity, with maximum increases of 94.8% for lamps, 82.3% for filters, 200.8% for fiber optics and 361.5% for all three parts. According to the manufacturer of radiometer, curing light is considered as unsuitable for use with a reading of above $300mW/cm^2$ by the radiometer. Applying these criteria to the present study, 64.4% of the curing units required repair or replacement. The results of this study indicated that the light intensities of the curing units used in dental practice were lower than optimum level.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2018.04a
• /
• pp.21-21
• /
• 2018

본 연구는 북방계 식물에 속하는 두메우드풀[Woodsia ilvensis (L.) R.Br.]의 전엽체 증식 및 포자체 형성을 위한 적정방법을 구명하고자 수행되었다. 식물재료는 경상북도 의성군 일대에서 채취한 후 청주의 일반하우스에 이식하여 재배하였다. 포자 성숙기인 8월에 채종하여 발아시켰으며, 포자로부터 획득한 전엽체를 8주간 계대하면서 실험재료로 사용하였다. 전엽체 300mg을 메스로 다진 후 배지농도 및 종류(Knop, 1/4, 1/2, 1 및 2MS)를 달리하여 8주간 배양하였다. 배양실의 온도는 $25{\pm}1.0^{\circ}C$, 광도는 $30{\pm}1.0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(16/8h)로 조절되었다. 연구의 결과, 배지구성물질의 농도가 높았던 2MS배지에서 전엽체의 생체중이 12.4g으로 41배 증가하여 가장 높은 증식율을 나타냈다. 또한 배지구성물질의 농도가 적을수록 생체중의 증가폭도 함께 감소하는 경향을 보였다. 포자체 형성에 적합한 토양조건을 확인하고자, 원예상토, 피트모스, 펄라이트 및 마사토의 비율을 달리한 5종류의 혼합토양을 조성하여 사각분($7.5{\times}7.5{\times}7.5cm$)에 충진하였다. 다음으로 전엽체 1g을 핸드블랜더로 10초간 분쇄 후 충진된 사각분 위에 고르게 분주하여 14주간 재배하였다. 재배환경은 온도 $25{\pm}1.0^{\circ}C$, 광도 $43{\pm}2.0{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(16/8h) 및 습도 $72{\pm}2.0%$로 조절되었다. 지베렐린 수용액이 포자체 형성에 미치는 영향을 조사하고자, 선행연구에서 선발된 토양조건을 기준으로 침지농도(0, 50, 100, $200mg{\cdot}L^{-1}$)를 조절하여 1시간 침지 후 상기와 동일한 방법으로 재배하였다. 연구의 결과, 원예상토와 펄라이트 또는 마사토를 2:1(v:v)로 혼용한 토양에서 사각분 당 109.5, 128.8개의 포자체가 형성되었다. 한편, 피트모스가 첨가된 처리는 포자체의 형성이 억제되는 경향을 나타냈다. 지베렐린 50과 $100mg{\cdot}L^{-1}$ 수용액에 침지한 처리에서 무처리에 비해 많은 사각분 당 각 177.0, 181.7개의 포자체가 형성되었으며, 생육도 양호하였다.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.8 no.1
• /
• pp.30-42
• /
• 2006

This experiment was conducted to investigate current situation and plant grouping by light and watering of mingled several cacti and succulents in a pot. The main 11 cacti are consist of Myrtillocactus geometrizans (Mart.) Cons., Gymnocalycium mihanovichii var. friedrichii Werd., Marginatocereus marginatus(DC.) Backbg., Eriocactus leninghausii (Hge. Jr.) Backbg, Notocactus scopa (Spreng.) Berg., Lobivia nealeana Backbg., Mammillaria elongata var. intertexta (DC.) SD., Pseudoespostoa (Vp1.) Backbg., Mammillaria albilanata Backbg., Mammillaria klissingiana Bod. and Espostoa lanata (HBK.) Br. & R. The main 10 succulents are Kalanchoe thyrsifolia Harv., Portulacaria afra var. foliis-variegatis Jacobs., Crassula perforata Thunbg., Echeveria pulvinata Rose, Aeonium arboreum cv. atropurpureum., Echeveria lauii Moran & J. Meyran, Pachypodium lamerei Drake, Sedum rubrotinctum cv. Aurora Boom., Aloe mitriformis Mill., and Euphorbia coerulescens Haw. The cacti were native to Mexico, Brazil, Peru, Paraguay, Ecuador, etc. The sucullents were native to Mexico, Africa, Gran Canaria, Madagascar, etc. Most of all the cacti and sucullents in the experiment are growing well under full sun or light shade, however Portulacaria afra var. foliis-variegatis Jacobs, and Sedum rubrotinctum cv. Aurora Boom. did not influenced by light. And all the plants require a little or moderate watering. Thus, planting by similar required water and light, when growing in a pot of several cacti and succulents, might be decreased the rate of death causing by their different plant physiology.

• Analytical Science and Technology
• /
• v.16 no.5
• /
• pp.399-406
• /
• 2003

This study was conducted to find out the analysis condition of selenium(Se) in oil refinery wastewater with a high concentration of Se using the atomic absorption spectrometry with hydride generation system (HG-AAS). From various experiments that reduced Se(VI) to Se(IV), the optimum pretreatment condition was determined to be a sample volume of 10 mL, HCl 10 mL, with a 30 min heating time in a water bath. In oil refinery wastewater, as the concentration of organics and constitution became higher, the recovery rates of Se decreased. Therefore, three acid digestion methods ($HNO_3/HClO_4$ digestion, $KMnO_4$ digestion, and microwave acid digestion) were tested on the recovery rates of Se in reference to the digestion of organics, petroleum and oxidation from organic Se(org.), Se(IV) to Se(VI). The experiment results showed that the average recovery rate of Se was the highest in microwave acid digestion, although all of the digestions were more than 90%. In consequence, the pretreatment procedure of microwave digestion followed by HCl addition was the most suitable for selenium analysis in oil refinery wastewater by using HG-AAS.