• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제1권1호
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• pp.51-59
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• 1997

Two comparative poplar clones (I-214: Populus euramericana, Peace: P koreana x P. trichocarpa) were exposed to two $CO_2$ concentrations (350 or 2,000 ${\mu}L\;L^{-1}\;CO_2)$ for 21 days. When both poplar clones were compared at growth conditions, the net photosynthetic rate $(P_N)$ in $CO_2-enriched$ (2,000 ${\mu}L\;L^{-1}\;CO_2=C_{2,000})$ plants become about $50-60\%$ higher than that of 350 ${\mu}L\;L^{-1}\;CO_2(=C_{350})$ plants on 7 days treatment. But the enhancement of $P_N$ by high $CO_2$ was not maintained throughout all the experimental period. At 21 days, there was no difference of photosynthetic rates between $C_{350}\;and\;C_{2,000}$ plants. In contrast with photosynthesis, the response of leaf conductance to the elevated $CO_2$ concentration was very different between I-214 and Peace. During all experimental period, leaf conductance $(g_s)$ of $C_{2,000}$ plants is $50\%$ lower than that of the $C_{350}$ plants for I-214, while there is no difference of $g_s$ between the plants of $C_{350}\;and\;C_{2,000}$ on for Peace. The results of gs in Peace indicate that decreased photosynthetic rate after 21 days in $C_{2,000}$ on plants for two poplar clones is possibly due to non-stomatal factors. To investigate the non-stomatal factors, starch accumulation and ribulose-1,6-bisphosphate carboxylase (RuBPCase) were measured. We found significant accumulation of starch in two poplar clones exposed to high $CO_2,$ especially starch of I-214 in $C_{2,000}$ become 3.5 times higher than in $C_{350}$ plants at 21 days. This suggests that high proportion of photosynthates was directed into starch. After 21 days, the activity of ribulose-1, 6-bisphosphate carboxylase of $C_{2,000}$ plants become decreased in $40-50\%$ compared with that of the $C_{350}$ plants. Two poplar clones show the same trend to RuBPCase declines under high $CO_2$ concentration, although the decline is more significant for I-214. The results reported here suggest that starch accumulation and decreased RuBPCase activity in $C_{2,000}$ plants can be partly ascribed to the loss of photosynthetic efficiency of high $CO_2-grown$ poplar plants.

• 한국약용작물학회지
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• 제27권1호
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• pp.30-37
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• 2019

Background: This study was conducted to investigate the changes in the photosynthetic parameters, chlorophyll content, chlorophyll fluorescence, and growth characteristics of Aruncus dioicus var. kamtschaticus seedlings under different shading treatments. Methods and Results: The shading treatment was regulated with the shading level (non-shaded, 35%, 55%, and 75% shading). Photosynthetic activities, such as net photosynthetic rate, stomatal conductance, stomatal transpiration rate, and performance index on absorption basis ($PI_{ABS}$)were the highest under 35% shading ($4.36{\mu}mol\;CO_2{\cdot}m^{-2}{\cdot}s^{-1}$, $54.2mmol\;H_2O{\cdot}m^2{\cdot}s^{-1}$, $0.66mmol\;H_2O{\cdot}m^{-2}{\cdot}s^{-1}$, and 1.3, respectively), and the lowest under 75% shading. This implies that the decrease in net photosynthetic rate may be due to an inability to regulate water and $CO_2$ exchanged through the stomata. Thechlorophylla, b, and a + b contents were increased with elevating shading level and the chlorophyll a/b ratio showed non-significant differences. It was found that the dry weight (leaf, shoot, and whole) was the highest (1.14 g, 0.49 g, and 2.31 g, respectively) under 35% shading and the t/R ratio was the highest under 75% shading. Conclusions: It is concluded that 75% shading exhibited a strong reduction of photosynthetic activity, and 35% shading showed the best conditions for the early growth and cultivation of A. dioicus var. kamtschaticus.

• BMB Reports
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• 제38권4호
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• pp.481-485
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• 2005

The response of Spirulina (Arthrospira) platensis to high salt stress was investigated by incubating the cells in light of moderate intensity in the presence of 0.8 M NaCl. NaCl caused a decrease in photosystem II (PSII) mediated oxygen evolution activity and increase in photosystem I (PSI) activity and the amount of P700. Similarly maximal efficiency of PSII (Fv/Fm) and variable fluorescence (Fv/Fo) were also declined in salt-stressed cells. Western blot analysis reveal that the inhibition in PSII activity is due to a 40% loss of a thylakoid membrane protein, known as D1, which is located in PSII reaction center. NaCl treatment of cells also resulted in the alterations of other thylakoid membrane proteins: most prominently, a dramatic diminishment of the 47-kDa chlorophyll protein (CP) and 94-kDa protein, and accumulation of a 17-kDa protein band were observed in SDS-PAGE. The changes in 47-kDa and 94-kDa proteins lead to the decreased energy transfer from light harvesting antenna to PSII, which was accompanied by alterations in the chlorophyll fluorescence emission spectra of whole cells and isolated thylakoids. Therefore we conclude that salt stress has various effects on photosynthetic electron transport activities due to the marked alterations in the composition of thylakoid membrane proteins.

• 한국초지조사료학회지
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• 제7권3호
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• pp.122-127
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• 1987

This experiment was carried out to investigate the effect of shading degrees (0:full sunlight, 25, 50 and 75%) on the crop growth rate (CGR), net assimilation rate (NAR) and photosynthetic activity of grasses for obtaining the basic data on the development, management and utilization of pasture in the forest. For the test, different artificial shading houses were established and pasture species used in this study were orchardgrass, timothy, perennial ryegrass and ladino clover. The experiment was performed at Livestock Experiment Station, Suwon, in 1984-'85. The results obtained are summarized as follows. 1. The highest CGR was obtained at 0% (full sunlight) and 25% of shading, followed by 50 and 75% of shading degrees, in that order. CGR of orchardgrass and perennial ryegrass were higher than those of timothy and ladino clover. 2. NAR was significantly decreased as the shading degrees increased. The highest NAR was observed at perennial ryegrass plot. 3. The photosynthetic activity during summer season was the highest at 25% of shading, followed by 50, 0 and 75% of shading degrees. While, the photosynthetic activity during fall season was the highest at 25% of shading, followed by 50, 0 and 75% of shading degrees, in that order. Those of orchardgrass and perennial ryegrass were remarkably higher than that of timothy. 4. A significant positive correlation was obtained in the relationship between CGR and NAR of main grasses, regardless of pasture species and investigated date.

• 한국약용작물학회지
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• 제22권1호
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• pp.38-45
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• 2014

This study was performed to investigate the physiological responses of Oplopanax elatus by water condition. Drought stress was induced by withholding water for 26 days. The results show that $P_{N\;max}$, SPAD, gs, E and Ci were significantly decreased with decreasing of soil moisture contents. However, AQY and WUE were decreased slightly only at 26 day. This implies that photosynthetic rate is reduced due to an inability to regulate water and $CO_2$ exchange through the stomatal. According to JIP analysis, ${\Phi}_{PO}$, ${\Psi}_O$, ${\Phi}_{EO}$ and $PI_{ABS}$ were dramatically decreased at 21 day and 26 day, which reflects the relative reduction state of the photosystem II. On the other hand, the relative activities per reaction center such as ABS/RC, TRo/RC were significantly increased at 26 day. Particularly, Dio/RC and DIo/CS increased substantially under drought stress, indicating that excessive energy was consumed by heat dissipation. These results of chlorophyll a fluorescence show that the sensitivity changes photosystem II activity. Thus, according to the results, O. elatus was exhibited a strong reduction of photosynthetic activity to approximately 10% soil moisture contents, and JIP parameters could be useful indicator to monitor the physiological states of O. elatus under drought stress.

• 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

• 한국작물학회지
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• 제40권2호
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• pp.133-141
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• 1995

약용 식물의 추출액이 자가영양배양세포의 광합성전자전달계에 미치는 영향을 조사하기 위해 9종의 약용식물 추출액으로부터 종자발아, PA세포의 엽록소 억제정도, DCIP의 환원율, 세포 생존율, 광계 I의 전자전달활성, 단백질에 미치는 영향을 조사한 결과는 다음과 같다. 1. 식물의 추출액을 농도별로 처리하였을 때 10％ 처리시 전 식물체에서 상추의 발아억제 현상을 나타내었고, 특히 백두옹과 초오 추출물 10％ 처리시는 100％ 억제를 나타내었다. 2. 백두옹의 증류수 및 MeOH 추출액을 PA세포에 처리한 경우 엽록소의 생성을 100％ 억제 하 였다. 이는 광합성 전자전달 저해제로 알려진 DCMU 10-3M 처리와 동일한 억제 효과였다. 3. PA세포에 추출물 처리시 백두옹이 힐반응 억제가 가장 컸으며, 세포 생존력은 가장 낮았다. 4. 광합성 산소발생은 반하, 독활, 백두옹, 만형자 추출액 처리시 14-77％ 억제되었고, 특히 PA 세포 2ml 반응액에 백두옹 추출물 60rl 처리시 50％ 산소발생 억제를 나타내었다. 5. 추출액을 PA 세포에 처리한 후 단백질을 추출하여 SDS-PAGE를 이용하여 조사한 결과 대조구에 비하여 백두옹 추출물 10％ 처리에서 14KD, 31KD, 41KD, 53KD, 73KD의 밴드가 나타나지 않았다.

• 한국작물학회지
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• 제42권1호
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• pp.56-60
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• 1997

인공산성비를 처리하였을 때 작물이 입는 피해양상 상호간의 관계를 알아보기 위하여 벼(일품벼), 콩(만리콩), 감자(대지), 고추(풍촌)에 pH 1.8, 2.3, 2.8인 인공산성비와 PH 6.0인 인공비를 출아 또는 정식 후 30일 부터 수확기까지 2주 간격(감자는 1주 간격)으로 처리하여 얻은 결과는 다음과 같다. 1. 인공산성비에 의한 잎의 가시적 피해는 벼, 콩, 고추는 pH 1.8과 2.3처리에서는 갈색 반점으로 나타났고, pH가 낮을수록 피해가 더 심했다. 감자는 어느 pH의 인공산성비 처리에서도 가시적 피해가 없었다. 2. 엽록소 함량은 벼와 감자에서는 인공산성비 처리간에 차이가 없었지만 고추와 콩에서는 인공산성비 pH가 낮을수록 잎의 엽록소 함량이 감소하였다. 3. 광합성 능력은 벼에서는 인공산성비 pH간에 차이가 없었다. 그러나 콩, 감자, 고추는 pH 2.8과 6.0에서는 차이가 없었으나 pH 2.8이하에서는 pH가 낮을수록 광합성 능력이 감소하였다. 4. 벼, 콩, 감자의 수량은 인공산성비 pH간에 차이가 없었으나 고추에서는 인공산성비의 pH가 낮을수록 과장, 과경, 1 과중, 주당 과실수, 과실 수량은 감소하였다. 5. 산성비에 대한 내성이 큰 벼와 감자에서는 가시적 피해가 다른 조사형질과는 상관이 없었다. 한편 내성이 약한 콩과 고추에서 가시적 피해는 콩의 엽록소 함량과 광합성 능력, 고추의 광합성 능력과 수량간에 부의 상관이 있었다.

• 한국잡초학회지
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• 제7권2호
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• pp.139-143
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• 1987

제초제(除草劑) 처리(處理)가 수도(水稻) 및 잡초(雜草)의 광합성(光合成) 저해(沮害)에 미치는 영향(影響)을 구명(究明)하고자 태백(太白)벼와 농백(農白)을 공시(供試)하여 Butachlor. Perfluidon, Molis-M (Molinate/symetryne/MCPB), Propanil 및 Bentazon을 처리(處理)한후 경시적인 광합성량(光合成量)을 측정(測定)하였으며 아울러 물달개비(M. Vaginalis) 및 너도방동산이(C. Serotinus) 등(等)에 대해서도 검토(檢討)한 결과 다음과 같다. 1. 제초제(除草劑) 처리(處理)에 대한 수도(水稻) 광합성(光合成) 저해(沮害)는 Molis-M>Perfluidon>Butachlor 순(順)으로 심했으며 이앙후(移秧後) 26일(日)이 경과(經過)하연 90% 정도(程度) 회복(回復)되었다. 2. 약제처리별(藥劑處理別) 품종간(品種間) 반응(反應)은 Molic-M 처리(處理)가 일반계품종(一般系品種)보다 다수계품종(多收系品種)에서 광합성(光合成) 저해(沮害)가 심했으며 Butachlor 및 Perfluidone 처리(處理)는 품종간(品種間) 차이(差異)가 적었다. 3. Bentazon 및 Propanil 처리(處理)에 대한 벼의 광합성(光合成) 회복정도(回復程度)는 Bentazon은 처리후(處理後) 24시간(時間)에 90% 정도(程度) 회복(回復) 되었으나 Propanil은 48시간(時間)에는 78% 밖에 회복(回復)되지 못했다. 4. Bentazon 처리(處理)에 대한 벼 및 잡초(雜草)의 광합성(光合成) 반응을 보면 벼는 처리후(處理後) 24시간(時間)이 경과(經過)하면 90% 가까이 회복(回復)되었으나 너도방동산이 및 물달개비는 회복(回復)되지 뭇하고 고사(枯死)하였다.

• 한국환경과학회지
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• 제15권12호
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• pp.1093-1101
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• 2006

In the present study we studied the growth, photosynthetic traits and protective mechanisms against oxidative stress in the primary loaves of cucumber (Cucumis sativus L.) seedlings with or without UV-B treatment. Cucumber seedings were irradiated with UV-B for 10 days in environment-controlled growth chambers. The primary leaves irradiated with UV-B showed reduction in leaf length and decreased biomass production. The reduced biomass production seemed to be due to a negative effect of UV-B radiation on the photosynthetic process. Changes in chemical properties of leaf, such as chi a/b ratio affected photosynthesis. UV-B significantly affected chl b content compared with chi a in the light harvesting complex resulting reduced photosynthetic activity Fv/Fm decreased with an UV-B stress, suggesting that the photosynthetic apparatus, and particularly, PS II was damaged under UV-B stress. Malondialdehyde(MDA) concentration which represents the state of membrane lipid peroxidation Increased significantly under UV-B stress confirming an oxidative stress. UV-B exposure with SA solution(0.1-1.0 mM) can partially ameliorated some of the detrimental effects of UV-B stress. Leaf injuries including loss of chlorophyll and decreased ratio of Fv/Fm were reduced with combined application of UV-B and SA. ABA and JA showed similar mode of action in physiological effects on photosynthetic activities though the levels were lower than those from SA treated plants. Chloroplast ultrastructure was also affected by UV-B exposure. The thickness of leaf tissue components decreased and the number of grana and thylakoids was reduced in chloroplast applied UV-B or SA alone. At combined stress granal and stromal thylakoids were less affected. The leaves under combined stress acquired a significant tolerance to oxidative stress. From these results, it can be suggested that SA may have involved a protective role against UV-B induced oxidative damage.