• Journal of Ecology and Environment
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• 제32권3호
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• pp.149-158
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• 2009

American sycamore seedlings were grown in chambers with two different ozone concentrations ($O_3$-free air and air with additional $O_3$) for 45 days. Both the control and the $O_3$ chambers included non-fertilized and fertilized plants. After 18 days of $O_3$ fumigation, seedlings were placed in a clean chamber for 27 days. Seedlings under ozone fumigation showed a significant decrease in pigment contents and photosynthetic activity, and a significant increase in lipid peroxidation. Fertilization enhanced physiological damage such as the inhibition of photosynthetic activity and the increase of lipid peroxidation under ozone fumigation. During the recovery phase, the physiological damage level of seedlings increased with ozone fumigation. In addition, physiological damage was observed in the fertilized seedlings. Superoxide dismutase (SOD) and glutathione reductase (GR) activities of $O_3$-treated seedlings increased up to 33.8% and 16.3% in the fertilized plants. The increase of SOD activity was higher in the fertilized plants than in the non-fertilized plants. Negative effects of ozone treatment were observed in the biomass of the leaves and the total dry weight of the fertilized sycamore seedlings. The $O_3$-treated seedlings decreased in stem, root and total dry weight, and the loss of biomass was statistically significant in the fertilized plants. In conclusion, physiological disturbance under normal nutrient conditions has an effect on growth response. In contrast, in conditions of energy shortage, although stress represents a physiological inhibition, it does not seem to affect the growth response.

• Journal of Photoscience
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• 제8권1호
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• pp.1-7
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• 2001

The deteriorative effect of ultraviolet-B(UV-B) radiation on photosynthesis was assessed by the simultaneous measurement of O$_2$ evolution and chlorophyll(Chl) fluorescence in green pepper. UV-B was given at the intensity of 1 W$.$m$\^$-2/, a dosage often encountered in urban area of Seoul in Korea, to detached leaves. Both Pmax and quantum yield of O$_2$ evolution was rapidly decreased, in a parallel phase, with increasing time of UV-B treatment. Chl fluorescence parameters were also significantly affected. Fo was increased while both Fm and Fv were decreased. Photochemical efficiency of PSII(Fv/Fm) was also declined, although to a lesser extent than Pmax. Both qP and NPQ were decreased similarly with increasing time of UV-B treatment. However, PS I remained stable. The addition of lincomycin prior to UV-B treatment accelerated the decline in Fv/Fm to some extent, suggesting that D1 protein turnover may play a role in overcoming the harmful effect of UV-B. The amount of photosynthetic pigments was less affected than photosynthetic response in showing decline in Chl a and carotenoids after 24 h-treatment. Presumptive flavonoid contents, measured by changes in absorbance at 270 nm , 300 nm and 330nm, were all increased by roughly 50% after 8 h-treatment. Among antioxidant enzymes, activities of catalase and peroxidase were steadily increased until 12h of UV-B treatment whereas ascorbate perxidase, dehydroascorvate reductase and glutathione reductase did not show any significant change. The results indicate that deteriorative effect of UV-B on photosynthesis precedes the protection exerted by pigment synthesis and antioxidant enzymes.

• KSBB Journal
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• 제14권4호
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• pp.414-421
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• 1999

본 연구에서는 미세조류의 배양액을 통한 빛의 전달특성을 수식적으로 표현하고 이를 바탕으로 광합성 활성을 예측할 수 있는 수학적 모델을 구축하였다. 먼저 미세조류의 배양액에서의 빛의 거동은 Beer-Lambert 식으로서 개략적으로 표현할 수 있었다. 미세조류의 광합성을 산소생산속도로서 나타낸 결과 미세조류의 농도가 높은 경우 낮은 농도에 비하면 단위 부피당 활성은 크게 나타난 반면 단위 건조중량당 활성은 오히려 낮게 나타났다. 이렇게 운전조건에 의존적인 광반응곡선을 예측하기 위하여 국부적인 광합성 활성을 가정하고 이를 전체부피에 대하여 평균하는 방버으로 수학적인 모델을 구축하였다. 또한 실험결과를 이용하여 고유 매개변수를 추정하였으며 예측치와 실험치를 비교한 결과 우수한 일치성을 확인하였다. 모델을 이용하여 광합성 활성에 크게 영향을 미치는 빛의 세기, 세포농도 및 빛의 투과특성과 같은 주요 운전조건에 대하여 그 영향을 살펴보았다. 그 결과 빛의 세기가 강할수록 광합성 활성은 증가하지만 광합성효율은 감소하는 경향을 확인할 수 있었다. 미세조류의 세포농도의 경우 단위 부피당 산소생산속도를 위한 최적의 농도가 존재함을 알 수 있었으며 이는 조사되는 빛의 세기에 따라 변화하였다. 빛의 투과거리가 짧을수록 광합성 효율은 증가하지만 충분히 강한 빛이 공급될 경우에는 일정한 투과거리까지는 최고치를 유지하였다. 결론적으로 광생물반응기의 성능을 예측하고 최적조건을 결정하는데 제시된 모델이 유용하게 사용될 수 있을 것으로 판단된다

• The Plant Pathology Journal
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• 제16권5호
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• pp.257-263
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• 2000

Infection with rice blast fungus (Magnaporthe grisea) significantly reduced foliar net photosynthesis (A) of rice cultivars: Ilpoom, Hwasung, and Choochung in greenhouse experiments. By measuring the amount of diseased leaf area with a computer image analysis system, the relation between disease severity (DS) and net photosynthetic rate was curvilinearly correlated (r=0.679). Diseased leaves with 35% blast symptom can be predicted to have a 50% reduction of photosynthesis. The disease severity was linearly correlated (r=0.478) with total chlorophyll (chlorophyll a and chlorophyll b) per unit leaf area(TC). Light use efficiency was reduced by the fungal infection according to the light response curves. However, dark respiration (Rd) did not change after the fungal infection (p=0.526). Since the percent of reduction in photosynthesis greatly exceeded the percent of leaf area covered by blast lesions, loss of photosynthetic tissue on an area basis could not by itself account for the reduced photosynthesis. Quantitative photosynthetic reduction can be partially explained by decreasing TC, but cannot be explained by decreasing Rd. By photosynthesis (A)-internal CO$_2$ concentration (C$_i$ curve analysis, it was suggested that the fungal infection reduced ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, ribulose-1,5-bisphosphate (RuBP) regeneration, and inorganic phosphate regeneration. Thus, the reduction of photosynthesis by blast infection was associated with decreased TC and biochemical capacity, which comprises all carbon metabolism after CO$_2$ enters through the stomata.

• 한국작물학회지
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• 제51권4호
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• pp.303-309
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• 2006

The study examined the effects of $CO_2$ enrichment on growth of soybean (Glycine max). Two soybean varieties were used, Taekwang and Cheongja. The plants were grown in growth chambers with a 12-h photoperiod and a day/night temperature of $28/21^{\circ}C$ at the seedling stage and $30/23^{\circ}C$ from the flowering stage. The plants were exposed to the two elevated $CO_2$ levels of 500 and 700 ppm and the ambient level of 350 ppm. Results of the experiment showed that at the second-node trifoliate stage of the two varieties, the elevated $CO_2$ increased plant height, leaf area and dry weight. The elevated $CO_2$ also raised the photosynthetic rate of soybean as compared to the ambient level. From the beginning bloom stage to the full maturity stage of the two varieties, the elevated $CO_2$ increased plant height, leaf area, seed weight and photosynthetic rate. The stomatal conductance and transpiration rate decreased on long days relative to short days of treatment. Through the entire stages, the elevated $CO_2$ increased the water use efficiency of soybean plants because stomatal conductance and transpiration rate decreased at the elevated $CO_2$ levels relative to the ambient level.

• 한국작물학회지
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• 제49권2호
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• pp.100-104
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• 2004

This study was conducted to investigate the effect of the salinity on growth, inorganic ion content, and photosynthetic rate ($\textrm{P}^{N}$) in Korean ginseng (Panax ginseng C.A. Meyer) with complex fertilizer (CF) and NaCl concentrations. The salinity was applied to plant using NaCl and CF, and controlled an EC as 0.0, 1.0, 2.0 and 3.0 dS $\textrm{m}^{-1}$. The salinity treated three times at 35, 42 and 49 d after transplanting. The leaf area in different electrical conductivity (EC) decreased only the higher NaCl 1.0 dS $\textrm{m}^{-1}$. The root growth increased with CF and especially, it was two times higher at 3.0 dS $\textrm{m}^{-1}$ than that of control. But the root growth sharply decreased with NaCl compared to CF. The light saturation point of Korean ginseng was around 100 $\mu\textrm{mol}\;\textrm{m}^{-2}\textrm{s}^{-1}$ photosynthetically active radiation (PAR), and $\textrm{P}^{N}$ increased as CF increased but decreased with NaCl especially at the late growth stage. The $\textrm{Na}^{+}$ content in Korean ginseng increased sharply with NaCl.

• 한국초지조사료학회지
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• 제42권3호
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• pp.208-214
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• 2022

Drought stress is a condition that occurs frequently in the field, it reduces of the agricultural yield of field crops. The aim of the study was to screen drought-adapted genotype of Italian rye grass. The experiments were conducted between the two Italian ryegrass (Lolium multiflorum L.) cultivars viz. Hwasan (H) and Kowinearly (KE). The plants were exposed to drought for 14 days. The results suggest that the morphological traits and biomass yield of KE significantly affected by drought stress-induced oxidative stress as the hydrogen peroxide (H₂O₂) level was induced, while these parameters were unchanged or less affected in H. Furthermore, the cultivar H showed better adaptation by maintaining several physiological parameter including photosystem-II (Fv/Fm), water use efficiency (WUE) and relative water content (RWC%) level in response to drought stress. These results indicate that the cultivar H shows improved drought tolerance by generic variation, improving photosynthetic efficiency and reducing oxidative stress damages under drought stress. These findings can be useful to the breeder and farmer for improving drought tolerance in Italian rye grass through breeding programs.

• 생물환경조절학회지
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• 제19권4호
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• pp.203-209
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• 2010

연구는 관엽식물 4종을 배지종류, 광도 및 이산화탄소 농도를 달리하여 식물의 광합성 반응을 조사하고, 그 결과에 기초하여 실내환경 조절에 효율적인 식물을 선정하고자 실시하였다. 식물재료로는 싱고니움, 디펜바키아, 쉐프렐라 홍콩, 드라세나를 사용하였으며, 성분과 성질이 다른 두 배지(peatmoss, hydroball)에 각각 재배하였다. 광도는 PPFD 0, 30, 50, 80, 100, 200, 400, $600{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$의 수준으로 조절하고, 이산화탄소 농도는 0, 50, 100, 200, 400, 700, 1000, $1500{\mu}mol{CO_2}{\cdot}mol^{-1}$의 수준으로 처리하였다. 광도 및 엽육내 $CO_2$ 농도변화에 따른 관엽식물의 광합성 반응을 조사한 결과, 약광에서의 광합성 능력을 나타내는 순양자수율은 쉐프렐라 홍콩과 디펜바키아에서 높게 나타났으며, 두 실내식물은 고농도의 이산화탄소 환경에서도 다른 두 식물에 비해 높은 광합성율을 기록했다. 드라세나 와네키는 두 조건 모두에서 가장 낮은 광합성 효율을 보였다. 두 배지 처리에 따라서는 각각의 관엽식물에서 엇갈린 광합성 반응이 관찰되었다. 쉐프렐라 홍콩은 피트모스 배지에서 광과 이산화탄소 증가에 따라 하이드로볼 배지에 비해 높은 광합성 속도를 보였지만, 디펜바키아는 그와는 정반대로 하이드로볼 배지에서 더욱 높은 광합성율을 기록했다. 싱고니움의 경우는 광처리에 의해서는 피트모스 배지에서 높은 광합성율을 보였지만 이산화탄소 처리에서는 배지간 차이가 없었다. 가장 낮은 광합성 효율을 보인 드라세나 와네키는 광에 의한 배지간 차이가 없었으며, 이산화탄소 증가시에는 피트모스에서 다소 높은 광합성율을 보였다. 따라서 실험한 4가지 관엽식물 중 광합성 효율이 가장 높았던 쉐프렐라 홍콩이나 하이드로볼 배지에서 높은 효율을 보인 디펜바키아가 실내 공기정화 및 실내 환경조절에 적합할 것으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제1권2호
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• pp.111-115
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• 1991

The green alga, Dunaliella salina under fed-batch cultivation produced 51.12 mg of hydrocarbon per liter with maintaining 0.313 (g dry wt/l). About 20% of hydrocarbon production yield based on dry biomass was obtained from both batch and fed-batch processes. Optimum culture conditions of light intensity, pH and salt concentration were obtained as 0.0080 (kJ/$cm^2$/h), 8.0 and 1.4 (g of NaCl/l), respectively by response surface analysis. The production of hydrocarbons in D. salina was closely correlated to cell growth. Fed-batch cultivation produced more hydrocarbons and maintained better cell growth than a batch process.

• 아시안잔디학회지
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• 제11권4호
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• pp.271-280
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• 1997

The short green period of zoysiagrass has been a problem in using for turf. This study was performed to check growth response of several wintergrasses under sunny and shady area in Korea. Wintergrasses of 5 species, 27 cultivars introduced from U.S.D.A., were used in this study. After establishment, two fluctuations of top growth were observed which varied according to the species; first, due to drought in May, second, due to high temperature and humidity from July to August. Red fescues and perennial ryegrasses showed severe growth retardation in sunny area during summer period. Kentucky bluegrasses and tall fescues maintained good Qualities nearly all the year round arid showed slight disease infections. Kentucky bluegrass 'Kenblue' and red fescue 'Agram' grown under shady area showed higher photosynthetic ability than under sunny area, except the temperature range from 30˚C to 40 ˚C under 40,000 lux light in red fescue 'Agram'. And the phorosynthesis was decreased at the temperature range from 35 ˚C to 40 ˚C. Key words: Wintergrass, Top growth, Visual rating, Photosynthesis, Poa pratensis. Festuca arundinacea, Pestuca rubra. Lolium perenne, Agrostis stolonifera.