• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제3권2호
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• pp.121-129
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• 1999

Photosynthesis and transpiration rates were simultaneously measured in attached sunflower leaves(Helianthus annuusL. cv. Russian Mammoth) during exposure to $NO_2$ and $O_3$ to determine the effect of mixed gan on photosynthesis and the stomatal aperture. The application of $O_3$ alone reduced both the net photosynthetic and transpiration rates. An analysis of the $CO_2$ diffusive resistances indicated that the main cause affecting photosynthesis reduction during $O_3$ exposure was not the internal gas phase of the leaf $(rCO_2^{liq})$ but rather the liquid phase or mesophyll diffusive resistance $(rCO_2^{liq})$, suggesting that there is a very concomitant relation between photosynthetic reduction and $rCO_2^{liq}$. The application of NO2 alone caused a marked reduction of the net photosynthesis yet no significant reduction of transpiration, indicating that NO2 affects the $CO_2$ fixation processes with no inluence on the stomatal aperture. A greter reduction in the photosynthesis of sunflower plants was caused by the application of $NO_2$ alone as compared to a combination of $NO_2$ and $O_3$. $NO_2$ alone reduced the photosynthetic rate by 90%, whereas a mixture of NO2 and O3 reduced it by 50%.

• 한국양식학회지
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• 제7권1호
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• pp.1-7
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• 1994

긴잎돌김 (Porphyra pscudolineris Ueda)의 엽상체와 배양 사상체에 미치는 온도와 광도의 영향을 구명하였다. 엽상체와 사상체의 총 광합성의 적정 온도는 각각 $25\~30^{\circ}C$, $20^{\circ}C$로 나타났다. 엽상체와 사상체에서 광도에 따른 광합성율은 공히 10,000 lux 이상에서 광합성율이 일정한 값에 도달하는 광포화 곡선을 나타내었다. 엽상체의 광 보상점은 2,100 lux, 사상체의 광 보강점은 900 lux였으며, 사상체의 광합성능은 엽상체의 5-10배에 해당하였다. 이로써 사상체는 낮은 광도하에서도 광합성을 수행할 수 있음을 알 수 있다.

• 한국작물학회지
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• 제33권4호
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• pp.350-352
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• 1988

This study was carried out to know the influence of turbidity of submerged water on photosynthetic rate of rice plant after water submerging treatment. Rice plants were transplanted in the pot at maximum tillering stage and they were sumberged for 3days at meiotic stage, 20days after transplanting, in the plastic container which had the clear and turbid water temperature adjusted around 24 to $25^{\circ}C$. Photosynthetic rate at 6 hours recovery after submergence was 41.5 to 54.2% compared to the control, but in the case of cultivar 'Nagdongbyeo', it was rapidly increased by 97.3 to 104.6% in the clear water and by 68.6 to 77.5% in the turbid water at 2 to 4 days recovery after submergence. Photosynthetic rates per plants at 6 hours to 4 days recovery after submergence were 128.3 to 245.5 $C_2$ mg.hr.$^{-1}$, in 'Samgamgbyeo' and 71.1 to 162.4 $CO_2$, mgㆍhr.$^{-1}$ in 'Nagdongbyeo' Photosynthetic rate to respiration ratio of rice plant recovery after submergence was lower compared to control plant and it was lower in 'Nagdongbyeo' than that in 'Samgangbyeo'.ngbyeo' than that in 'Samgangbyeo'.gangbyeo'.pos;.

• 한국자원식물학회지
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• 제21권5호
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• pp.357-361
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• 2008

고품질의 곰취, 곤달비 및 한대리곰취를 지속적으로 생산할 수 있는 임간재배기술을 개발하고자 횡성군 둔내면의 산채마을 임간재배지에 생육중인 세 식물종의 광합성을 특성을 조사 비교하였다. 광도에 따른 곰취류의 광합성율의 평균은 광도가 높아질수록 높아지는 경향을 보였다. 광도에 따른 곰취의 광합성율의 평균은 광도가 높아질수록 높아지다가 1,600 PPFD에서 최대치인 $21.1{\mu}mol\;CO_{2}m^{-2}s^{-1}$를 보이고 2,000 PPFD에서는 낮아졌다. 한대리곰취가 $27.39({\mu}mol\;CO_{2}m^{-2}s^{-1})$로 가장 높은 광합성율을 보였고, 곰취, 곤달비 순으로 낮아졌다. 5월 27일 측정에서 모두 식물종간 통계적 유의차가 인정되었으며 광합성율은 한대리곰취, 곰취, 곤달비 순이었고, 6월 21일 측정 광합성율은 한대리금취, 곤달비, 곰취순이었다. 횡성군 둔내면 산채마을과 같은 해발고가 낮은 지역에서는 곰취나 곤달비 보다는 한대리곰취의 임판재배가 적합할 것이라 사료된다.

• ALGAE
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• 제31권1호
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• pp.49-59
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• 2016

Ulva pertusa, a common bloom-forming green alga, was used as a model system to examine the effects of elevated carbon dioxide (CO₂) and temperature on growth and photosynthetic performance. To do this, U. pertusa was grown under four temperature and CO₂ conditions; ambient CO₂ (400 μatm) and temperature (16℃) (i.e., present), elevated temperature only (19℃) (ET; i.e., warming), elevated CO₂ only (1,000 μatm) (EC; i.e., acidification), and elevated temperature and CO₂ (ET and EC; i.e., greenhouse), and its steady state photosynthetic performance evaluated. Maximum gross photosynthetic rates (GP_max) were highest under EC conditions and lowest under ET conditions. Further, ET conditions resulted in decreased rate of dark respiration (R_d), but growth of U. pertusa was higher under ET conditions than under ambient temperature conditions. In order to evaluate external carbonic anhydrase (eCA) activity, photosynthesis was measured at 70 μmol photons m⁻² s⁻¹ in the presence or absence of the eCA inhibitor acetazolamide (AZ), which inhibited photosynthetic rates in all treatments, indicating eCA activity. However, while AZ reduced U. pertusa photosynthesis in all treatments, this reduction was lower under ambient CO₂ conditions (both present and warming) compared to EC conditions (both acidification and greenhouse). Moreover, Chlorophyll a and glucose contents in U. pertusa tissues declined under ET conditions (both warming and greenhouse) in conjunction with reduced GP_max and R_d. Overall, our results indicate that the interaction of EC and ET would offset each other’s impacts on photosynthesis and biochemical composition as related to carbon balance of U. pertusa.

• 생물환경조절학회지
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• 제9권3호
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• pp.171-178
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• 2000

시설 오이재배에서 조절가능한 환경요인들, 즉 광도, $CO_2$ 농도, 온도 그리고 엽중 질소 농도의 변화에 따른 양액재배 오이 엽의 총광합성 속도를 측정하였다. 광보상점은 10~20$\mu$mol.m$^{-2}$ .s$^{-1}$ 정도로 낮았고 광포화점은 1000$\mu$mol.m$^{-2}$ .s$^{-1}$ 이상이었으며, 오이의 총광합성 속도는 온도가 상승할수록 증가속도는 감소하지만 지속적인 증가를 보였으나 24~32$^{\circ}C$ 사이에서 광합성 속도는 큰 차이를 보이지 않아 이 범위가 오이 생육에 대한 적정온도인 것으로 나타났다. $CO_2$ 보상점은 20-40$\mu$mol.mol$^{-1}$ 사이에 위치하였고 $CO_2$포화점은 1200$\mu$mol.mol$^{-1}$이상으로 나타났으며 엽중은 질소함량의 증가에 따른 잎의 총광합성 속도의 변화는 sigmoid형의 증가추세를 보였다. 요인들간의 상호작용 효과에서는 모든 경우 상승적으로 나타나, 한 요인의 수준이 증가함에 따라 타 요인의 수준의 증가에 따른 총광합성 속도도 상승적을 증가하였다. 각환경요인의 변화와 요인들간의 상호작용에 따른 총광합성 속도의 변화에 대한 수리적 모형을 개발하였다. 이들 모형은 시설 내 환경변이에 따른 오이의 생육 내지는 수량에서의 차이를 밝히는데 이용될 수 있으며 오이의 식물생장 모형이나 더 나아가 경영합리화를 위한 오이 생산 전문가 시스템의 개발에 필요한 기초 자료로 이용될 수 있을 것이다.

• 원예과학기술지
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• 제29권3호
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• pp.211-216
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• 2011

파프리카의 상하위엽의 광합성 속도 차이를 측정하고, 광합성 측정용 챔버를 이용한 광합성량 측정치와의 차이를 비교하여 보다 정밀한 파프리카 생육시의 $CO_2$ 요구도를 알아보고자 본 연구를 수행하였다. 광합성측정장치(LI-6400)를 이용하여 위치 별 파프리카의 광합성속도를 측정하였다. 또한 파프리카 개체의 $CO_2$ 소모량의 정량화를 위하여 환경조절이 가능한 밀폐 챔버를 제작하고, 챔버 내부의 $CO_2$ 농도의 감소량을 측정하여 식물이 이용한 $CO_2$를 정량화하였다. 파프리카의 상위엽과 하위엽에서 광도증가에 따른 광합성 속도 상위엽에서 증가량이 상대적으로 크게 나타났다. 제작한 챔버 내부의 $CO_2$ 농도를 $1,500{\mu}mol{\cdot}mol^{-1}$ 수준으로 설정한 후, 일사량 변화에 따른 챔버 내부의 $CO_2$ 농도를 이용하여 식물체에 의해 소모된 양을 계산하였다. 엽면적이 $7,533.4cm^2$인 파프리카의 경우, 적산광(x)에 따른 $CO_2$ 소모량은 다음과 같은 광합성량 추정 모델식으로 추정되었다: $y=-0.06234+3.671^*x/(2.589+x)$ ($R^2=0.9966^{***}$). $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ 광도범위에서 챔버를 이용한 파프리카의 광합성속도는 $3.4{\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$ 이었고, 상위엽과 하위엽에서의 광합성 측정기에 의한 데이터와 비교하여 중간 값을 나타내었다. 따라서 실제 대규모 농가에서 단위엽의 광합성 측정에 의하여 $CO_2$ 시비량을 계산하면 실제 필요량과 공급량 간에 큰 차이가 발생할 수 있다. 따라서 엽 광합성속도 이외에도 본 연구에서와 같이 챔버를 이용하여 파프리카 식물체 개체가 소비하는 $CO_2$량을 정량화한다면 상업용 온실에 필요한 $CO_2$ 시비량을 정확하게 추정할 수 있다.

• ALGAE
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• 제29권3호
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• pp.203-215
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• 2014

As global warming continues over the coming century, marine organisms will experience a warmer, more acidic ocean. Although these stressors may behave antagonistically or synergistically and will impact organisms both directly (i.e., physiologically) and indirectly (i.e., through altered species interactions), few studies have examined the complexities of these effects in combination. To address these uncertainties, we examined the independent and combined effects of elevated temperature and $pCO_2$ on the physiology of the adult sporophyte stage of giant kelp, Macrocystis pyrifera, and the grazing of the purple sea urchin Strongylocentrotus purpuratus. While elevating $pCO_2$ alone had no effect on M. pyrifera growth or photosynthetic carbon uptake, elevating temperature alone resulted in a significant reduction in both. However, when M. pyrifera was grown under elevated temperature and $pCO_2$ together, growth and photosynthetic carbon uptake significantly increased relative to ambient conditions, suggesting an interaction of these factors on photosynthetic physiology. S. purpuratus held under future conditions generally exhibited reduced growth, and smaller gonads than urchins held under present-day conditions. However, urchins fed kelp grown under future conditions showed higher growth rates, partially ameliorating this effect. Feeding rates were variable over the course of the experiment, with only the first feeding rate experiment showing significantly lower rates for urchins held under future conditions. Together, these data suggest that M. pyrifera may benefit physiologically from a warmer, more acidic (i.e., higher $pCO_2$) ocean while S. purpuratus will likely be impacted negatively. Given that kelp-urchin interactions can be important to kelp forest structure, changes to either of these populations may have serious consequences for many coastal environments.

• 한국초지조사료학회지
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• 제8권1호
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• pp.61-65
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• 1988

To examine the effects of light intensity on photosynthesis, corn and sorghum species were grown under shade cloths, which reduced light intensity by 25,50 and 75%. Photosynthetic rates were measured between 10 a.m. to noon on a clear day in early and mid - summer. 1. The degree of shading had a little effect on microenvironment. Air, soil and leaf temperatures were reduced as shade increased. 2. The degree of shading in early summer had relatively a little effect on photosynthesis of corn. However, the rates of photosynthesis in mid-summer decreased by 36%, 55% with relative light intensities of 50% and 25%, respectively. 3. The rate of photosynthesis was highly correlated with light intensity. The rates of photosynthesis with relative light intensities of 75,50 and 25% were decreased by 20, 40 and 5 4% in early summer, and by 17-53%, 36-64% and 5570% in mid-summer, respectively. 4. The 75% of light intensity had relatively little effect on dry matter yield of corn and sorghum species, however dry matter yield with 50 and 25% relative light intensities was decreased 17 and 36% in corn, 13-3 1 and 50-68% in sorghum species, respectively.

• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.817-822
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• 2000

A proper flashing light is expected to enhance microalgal biomass productivity and photosynthetic efficiency. The effect of flashing light on high-density Chlorella kessleri (UTEX 398) cultures was studied using light-emitting diodes. A frequency modulator was designed to flash LEDs, and the device successfully provided wide range of frequencies and various duty cycles of flashing. A relatively high frequencies of 10, 20 and 50 kHz were used in this study. These frequencies have very short flashing time ($2-50{\mu}s$), which corresponded to the time constant of the light reaction of photosynthesis. The specific oxygen production rates of photosynthesis under flashing light were compared with those under an equivalent continuous light in specially designed illumination cuvette. The specific oxygen production rates under flashing light were 5-25% higher than those under the continuous light. A range of cell concentration was discovered, where the benefit of flashing light was maximized. The photosynthetic efficiency was also higher under flashing light with frequencies of over 1 kHz, which was a clear indication of flashing light effect and the degree of mutual shading could by overcome by flashing lights, particularly at high-density algal cultures.