• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.537-542
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• 2004

To reveal the relationship between the changes in the growth and photo- synthesis induced by low dose radiation, red pepper (Capsicum annuum L.) plants were serially irradiated three times with gamma rays of 0.5, 1, 2, 3, and 4 Gy. The plant growth was monitored by the fresh weight, the stem length, and the leaf length & width. All the irradiation groups (0.5-4 Gy) were stimulated in growth at 1 day after the $1^{st}$ irradiation (DA1I), but rather inhibited at 3 days after the $3^{rd}$ irradiation (DA3I). The maximum photochemical efficiency (Fv/Fm), the photochemical quenching (qP), the non-:photochemical quenching (NPQ) and the apparent rate of the photosynthetic electron transport (ETR) were used to represent the changes in the photosynthesis by the serial irradiation. The irradiation groups except 0.5 Gy had higher Fv/Fm values at 3 DA3I than the control one. After the 3$^{rd}$ irradiation, the qP values appeared to be a little lower in the 1-4 Gy groups than in the control and 0.5 Gy ones. In contrast, the NPQ values were rather higher in the irradiation groups except 0.5 Gy. During the whole experimental period, the ETRs decreased in the control group but remained relatively constant in the 4-Gy one. In conclusion, the results obtained indicate that the stimulatory effect of ionizing radiation on the plant growth was determined by the incident dose of the single irradiation rather than by the cumulative one of the serial irradiation. They also demonstrate that the growth stimulation induced by a low dose radiation could not be positively correlated with an alteration in the photosynthesis. Additionally, we discuss in text that an ionizing radiation may partly protect the leaf senescence by delaying the development of the plants.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.673-679
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• 2012

This study was conducted to examine the effect of artificial light source and photoperiod on the growth of leaf lettuce (Lactuca sativa L.) 'Seonhong Jeokchukmyeon' in a closed-type plant production system. Seedlings were grown under 3 light sources, fluorescent lamp (FL, Philips Co. Ltd., the Netherlands), WL #1 (Hepas Co. Ltd., Korea), and WL #2 (FC Poibe Co., Ltd., Korea), each with 3 photoperiods, 12/12, 18/6, and 24/0 (Light/Dark). An irradiance spectrum analysis showed that FL has various peaks in the 400-700 nm range, while WL #1 and WL #2 have only one monochromatic peak at 450 and 550 nm, respectively. The greatest plant height, fresh and dry weights were obtained in the 24/0 (Light/Dark) photoperiod. The 24/0 (Light/Dark) photoperiod treatment promoted vegetative growth of the leaf area. Length of the longest root, number of leaves, fresh weight, and total anthocyanin contents were greater in FL than in either WL #1 or #2. The greatest chlorophyll fluorescence (Fv/Fm) was found in the 12/12 (Light/Dark) photoperiod with FL treatment. The energy use efficiency of the LED increased by about 35-46% as compared to FL. Results suggest a possibility of LED being used as a substitute light source for fluorescent lamp for lettuce cultivation in a plant factory system.

• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.273-279
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• 2015

Phaeodactylum tricornutum is a model diatom that its genomic information and biological tools are well established. In this study, a gene encoding (E)-4-hydroxy-3-methylbut-2-enyl diphosphate reductase (PtHDR), a terminal enzyme of the methylerythritol phosphate pathway regulating chlorophyll and carotenoid biosynthesis, was isolated from P. tricornutum. The isolated gene was cloned into pPha-T1 vector containing fcpA promoter to prepare pPha-T1-HDR plasmid. As a positive control, pPha-T1-eGFP plasmid was constructed with egfp gene. Stable nuclear transformation was carried out with these plasmids by particle bombardment method and zeocin resistant colonies of P. tricornutum were selected on f/2 agar plate. In result, transformation efficiency was evaluated according to the amount of plasmid DNA coated with gold particles. Integration of introduced plasmids was confirmed with genomic DNA of each transformant by polymerase chain reaction. The eGFP fluorescence was visible in the cytoplasm, indicating that eGFP was successively expressed in P. tricornutum system. The transcript level of exogenous Pthdr gene was evaluated with the obtained transformants. The results presented here demonstrated that introduction of Pthdr gene into P. tricornutum chromosome succeeded and expression of PtHDR was enhanced under the fcpA promoter.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.878-885
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• 2016

A study was conducted to examine the effects of light quality on the growth and phytochemical contents of ice plant in a closed-type plant production system. Seeds were sown in a 128-cell plug tray using rockwool. The seedlings were then transplanted into a deep floating technique system with recirculating nutrient solution (EC $1.5dS{\cdot}m^{-1}$, pH 6.5) in a closed-type plant production system. The nutrient solution was supplied at two weeks after transplanting with 2.0 mM NaCl concentration in all treatments for the development of the bladder cells. The three light sources with different light qualities used were as followed; FL (fluorescent lamps), combined RW LED (red:white = 7:3), and combined RBW LED (red:blue:white = 8:1:1) at $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD with a photoperiod of 14/10 hours (light/dark). The results showed that the FL treatment had the greatest growth enhancement effects on the leaf area and the fresh and dry weights of the shoots and roots. The SPAD values were significantly higher under the FL and RBW LED treatments, at 29.8 and 30.6, respectively. No significant difference was observed in salinity under all treatments. Chlorophyll fluorescence was significantly higher under the FL treatment. The total phenol content and antioxidant activity were the highest under the RBW LED treatment. The total flavonoid content was significantly higher under the RBW LED and FL treatments. Hence, the results indicate that the growth of ice plant was maximized under the FL treatment. The phytochemical contents were maximized under the RBW LED treatment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.4
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• pp.261-268
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• 2019

Climate change and drought stress are having profound impacts on crop growth and development by altering crop physiological processes including photosynthetic activity. But finding a rapid, efficient, and non-destructive method for estimating environmental stress responses in the leaf and canopy is still a difficult issue for remote sensing research. We compared the relationships between photochemical reflectance index(PRI) and various optical and experimental indices on soybean drought stress under climate change conditions. Canopy photosynthesis trait, biomass change, chlorophyll fluorescence(Fv/Fm), stomatal conductance showed significant correlations with midday PRI value across the drought stress period under various climate conditions. In high temperature treatment, PRI were more sensitive to enhanced drought stress, demonstrating the negative effect of the high temperature on the drought stress. But high CO₂ concentration alleviated the midday depression of both photosynthesis and PRI. Although air temperature and CO₂ concentration could affect PRI interpretation and assessment of canopy radiation use efficiency(RUE), PRI was significantly correlated with canopy RUE both under climate change and drought stress conditions, indicating the applicability of PRI for tracking the drought stress responses in soybean. However, it is necessary to develop an integrated model for stress diagnosis using PRI at canopy level by minimizing the influence of physical and physiological factors on PRI and incorporating the effects of other vegetation indices.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.1
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• pp.28-34
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• 2017

This study was carried out to investigate growth characteristics of woody plants that are widely used indoors in accordance with irrigation frequency and to find the optimum irrigation conditions for plants that help to improve the indoor environment. Four woody plants used in this study included Ardisia pusilla, Clusia rosea, Fatsia japonica, and Ficus elastica. They were planted in pots with a diameter of 10cm and cultivated in three different irrigation frequencies: two times per week, one time per week, and one time per two weeks. After 120 days, they were measured by plant height, fresh weight, dry weight, SPAD value, leaf color, leaf water potential, chlorophyll fluorescence (Fv/Fm), and photosynthetic rate. The average soil moisture content was $48.8{\pm}2.1%$ in two times per week, $25.2{\pm}4.4%$ in one time per week, and $10.3{\pm}2.4%$ in one time per two weeks. For A. pusilla, leaf water potential was higher, and Fv/Fm value was 0.731 in two times per week irrigation, showing more wetness. For A. pusilla, F. japonica and F. elastica photosynthetic rate was significantly lower in one time per two weeks irrigation, appearing to be more sensitive to drying than C. rosea. When irrigated one time per week, with the soil's volume average moisture content of 25%, all four woody plants used in this experiment proved to grow smooth. Thus, it was determined to be good for use in indoor landscaping.

• Food Science and Preservation
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• v.22 no.6
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• pp.804-810
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• 2015

Salvia miltiorrhiza has been used for treating heart and liver disease. In the present study, the influences of temperature on photosynthetical capacity of S. miltiorrhiza under controlled cultivation environment using growth chamber were investigated because of providing information about growth and secondary metabolite synthesis. And effect of harvesting time on growth properties and constituents such as salvianolic acid B, cryptotanshinone, tanshinone I, tanshinone IIA were evaluated. Maximum photosynthesis rate ($5.102{\mu}mol\;CO2/m2/s$) and net apparent quantum yield ($0.147{\mu}mol\;CO2/m2/s$), stomatal conductance (0.035 mmol/m2/s) and water use efficiency ($7.108{\mu}mol\;CO2/mmol\;H2O$) was highest at $20^{\circ}C$. Results of chlorophyll fluorescence showed that elevated temperature had contributed to reduce a quantum yield and electron flux in photosystem. This result demonstrated that favorable temperature condition was determined at $20^{\circ}C$. Contents of salvianolic acid B, cryptotanshinone, tanshinone I and tanshinone IIA was highest in root sample harvested at 20 March, whereas growth and yield of S. miltiorrhiza had no significant differences with harvesting time. Therefore, this study shows that temperature play an important role in photosynthetic activity and harvesting time have influence upon accumulation of constituents in root of S. miltiorrhiza.

• Horticultural Science & Technology
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• v.19 no.2
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• pp.153-158
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• 2001

Leaf spots in Saintpaulia leaves are caused by temperature drop shock (TDS). This TDS-mediated leaf injury has not been reported in other plants besides Saintpaulia. To investigate how many and what kinds of plants are susceptible to temperature drop shock, Gesneriaceae and Acanthaceae plants were treated with TDS (from $30^{\circ}C$ to $15^{\circ}C$ or $5^{\circ}C$). Yellow or brown spots were found in 26 species or cultivars of 10 genuses of Gesneriaceae plants and in 8 species or cultivars of 7 genuses of Acanthaceae plants. Morphologically and anatomically no similarity was observed among the plants susceptible to TDS. Some plants have very thin and hard leaves, whereas other plants have thick and soft leaves. In spite of this non-similarity, the injury was restricted only to palisade cells as those of Saintpaulia leaves. Also the rapid and irreversible reduction of chlorophyll fluorescence was observed soon after TDS treatment in those plants. These results indicate that leaf injury induced by TDS is a more widespread leaf injury than has previously been thought.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.59-59
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• 2019

본 연구는 몇 가지 광량 조건하에서 자생 동백나무속 상록활엽 목본 2종의 생육 및 엽록소 형광 반응을 조사함으로써 실내 도입가능 여부를 판단하고자 수행되었다. 연구재료는 2년생 차나무[Camellia sinensis (L.) Kuntze] 삽목묘와 3년생 동백나무(C. japonica L.) 실생묘를 사용하였다. 실내 광환경의 사전조사를 토대로 광량을 10, 50, 100 및 200 PPFD (${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$)로 달리하였으며, 실험기간 동안 광 주기(12/12 h), 온도($25{\pm}1^{\circ}C$) 및 습도($55{\pm}3%$)를 통일하였다. 총 8주간 재배하였으며, 유리온실에서 동일기간 동안 재배중인 식물을 대조구로 비교하였다. 연구의 결과, 차나무는 50 PPFD 이상의 조건에서 초장, 줄기직경, 엽수 및 엽장 등의 생육이 대조구와 유사한 수준이었다. 그러나 10 PPFD에서는 모든 식물체의 잎이 말리거나 떨어지는 등의 관상가치가 저하되었으며, 엽록소 함량은 유의적으로 광량에 반비례하는 경향을 보였다. 엽록소 형광 반응은 100, 200 PPFD의 광량에서 모든 조사 항목이 대조구와 유사하였다. 동백나무는 50 PPFD에서 25%의 고사율이 나타냈다. 100 또는 200 PPFD에서 전반적인 생육이 대조구와 유사하거나 우수하였으며, 엽폭과 SPAD는 광량에 관계없이 유의적인 차이가 없었다. 또한 100, 200 PPFD의 엽록소 형광 반응은 모든 조사 항목에서 대조구와 비슷하거나 우수한 결과를 보였다.

• Journal of agriculture & life science
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• v.53 no.6
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• pp.13-21
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• 2019

The influences of light generated by LEDs on shoot growth and photosynthesis of Tea plant(Camellia sinensis L.) were evaluated. The growth characteristics were investigated after 45 days of culture under four different light qualities: fluorescent lamp, red LED, blue LED, red+blue+white LED. Shoot growth was promoted by red light, especially root length and area were further promoted under the red+blue+white LED. Also, T/R ratio and Chlorophyll content were highest in red+blue+white. Fluor Cam was used to measure the fluorescence images of the plants, inhibition of photochemical efficiency(Fv/Fm) were not changed in all treatment. However, non-photochemical quenching(NPQ) were found rapidly increasing in blue LED, these results were that blue LED were inhibit photosynthetic efficiency and must be considered for efficiently in vitro cultivation of the tea plant. The above results suggest that light qualities could be an important factor to foster in vitro growth of the species. Also, In order to produce healthy plants, it is effective to using light qualities of red+blue+white LED on in vitro culture of the tea plant. These results could be used to mass propagating shoot and produce of healthy seedling.