• Journal of Ecology and Environment
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• 제47권3호
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• pp.103-116
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• 2023

Background: This study analyzed the physiological adaptations of a woody plant, Vitex rotundifolia, in Goraebul coastal sand dunes from May to September 2022. Environmental factors and physiological of plants growing under field and controlled (pot) conditions were compared. Results: Photosynthesis in plants growing in the coastal sand dunes and pots was the highest in June 2022 and July 2022, respectively. Chlorophyll fluorescence indicated the presence of stress in the coastal sand dune environment. The net photosynthesis rate (P_N) and Y(II) were highest in June in the coastal sand dune environment and July in the pot environment. In August and September, Y(NPQ) increased in the plants in the coastal sand dune environment, showing their photoprotective mechanism. Chlorophyll a and b contents in the pot plant leaves were higher than those in the coastal sand dune plant leaves; however, chlorophyll-a/b ratio was higher in the coastal sand dune plant leaves than in the pot plant leaves, suggesting a relatively high photosynthetic efficiency. Carotenoid content in the coastal sand dune plant leaves was higher in August and September 2022 than that in the pot plant leaves. Leaf water and soluble carbohydrate contents of the coastal sand dune plant leaves decreased in September 2022, leading to rapid leaf abscission. Diurnal variations in photosynthesis and chlorophyll fluorescence in both environments showed peak activity at 12:00 hour; however, the coastal sand dune plants had lower growth rates and Y(II) than the pot plants. Plants in the coastal sand dunes had higher leaf water and ion contents, indicating that they adapted to water stress through osmotic adjustments. However, plants growing in the coastal sand dunes exhibited reduced photosynthetic activity and accelerated decline due to seasonal temperature decreases. These findings demonstrate the adaptation mechanisms of V. rotundifolia to water stress, poor soils, and high temperature conditions in coastal sand dunes. Conclusions: The observed variations indicate the responses of the V. rotundifolia to environmental stress, and may reveal its survival strategies and adaptation mechanisms to stress. The results provide insights into the ecophysiological characteristics of V. rotundifolia and a basis for the conservation and restoration of damaged coastal sand dunes.

• The Korean Journal of Ecology
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• 제24권6호
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• pp.335-339
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• 2001

The dynamic model was developed to simulate the photosynthetic rate of Phragmites communis stands in coastal ecosystem. The model was composed of the compartments of both climatic and biological variables. The former were photosynthetic photon flux density(PPFD), daily maximum- and minimum-temperature. The latter were combinations of the specific physiological responses of plant organs with the biomass of each organs. The PPFD and air temperature were calculated and using those values, gas exchange rate of each plant organ was calculated at every hour. The carbon budget was constructed using the modelled predictions. Analysis of annual productivity and fluxes showed that yearly gross population productivity, yearly population respiration and yearly net population productivity were 33.4, 21.3 and 12.1 $CO_2ton{\cdot}ha^{-2}{\cdot}yr^{-1}$, respectively. The final result was tested over two stands, produced promising predictions with regards to the levels of production attained. The model can be used to determine production potential under given climatic conditions and could even be applied to plant canopies with analogous biological characteristics.

• ALGAE
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• 제22권4호
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• pp.319-323
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• 2007

This study was conducted with using chlorophyll a fluorescence (indicated as photosynthetic activity) to examine the toxic effect of 96 h exposure of heavy metals and herbicides on the benthic diatom Nitzschia sp. which was isolated from pristine sediment in Pamquat Harbour, Nova Scotia, Canada. Samples of benthic diatom were exposed to 0, 0.01, 0.1 and 1 mg L–1 of copper, 0, 1, 10 and 100 mg L–1 of chrome (VI), 0, 2.45, 24.5 and 245 mg L–1 of paraquat dichloride, and 0, 4.37, 43.7 and 437 mg L–1 of alachlor during 96 hours. The effective quantum yield of photochemistry (ΔF/Fm’) was evaluated by subjecting light acclimated samples to saturating pulses of light using a pulse amplitude modulated (PAM) fluorometer. The impact of heavy metals on Nitzschia sp. photosynthesis was not severe in < 1 mg L–1 but in the high concentrations (> 1 mg L–1) clearly increased toxic stress during 96 h. Herbicides had a limited impact during the exposure period but clearly increased stress on the benthic diatom with increasing concentrations. Acute response of Nitzschia sp. to selected heavy metals and herbicides was characterized, and the capacity of a benthic diatom to tolerate and recover from toxic stress was assessed.

• ALGAE
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• 제29권1호
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• pp.27-34
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• 2014

Availability of nutrients is known to influence marine primary production; and it is of general interest to see how nutrient limitation mediates phytoplankton responses to solar ultraviolet radiation (UVR, 280-400 nm). The red tide diatom Skeletonema costatum was cultured under nitrate (N)-limited and N-replete conditions and exposed to different solar irradiation treatments with or without UV-A (315-400 nm) and UV-B (280-315 nm) radiation. Its photochemical quantum yield decreased by 13.6% in N-limited cells as compared to that in N-replete ones under photosynthetically active radiation (PAR)-alone treatment, and the presence of UV-A or UV-B decreased the yield further by 2.8 and 3.1%, respectively. The non-photochemical quenching (NPQ), when the cells were exposed to stressful light condition, was higher in N-limited than in N-replete grown cells by 180% under PAR alone, by 204% under PAR + UV-A and by 76% under PAR + UV-A + UV-B treatments. Our results indicate that the N limitation exacerbates the UVR effects on the S. costatum photosynthetic performance and stimulate its NPQ.

• Weed & Turfgrass Science
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• 제4권4호
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• pp.338-347
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• 2015

Reinforcement cells are used to aid grass growth and taken together, this serves to extend greenery beyond the conventional spaces of lawns, tree pits, gardens, and parks, and is advantageous to urban cities since space for greening is often limited. Drought has variable effects on plant life and the resilience of turf to drought resistance also varies with species. Changes in photosynthetic ability were more pronounced for media rather than grass species. The media of sand without organic matter was found to be least suited for drought resistance. Normalized difference vegetation index (NDVI) and digital image analysis (DIA) data were generally in favour of Zoysia species as oppose to A. compressus. In A. compressus, selective traits such as, a more extensive root system and lower specific leaf area (SLA) were not an underlying factor that assisted this grass with enhanced drought resistance. Generally, WUE was found to be strongly related to plant characterises such as overall biomass, photosynthetic features as well as the lushness indexes, and specific leaf area. This study found a strong relationship between WUE and a suite of plant characteristics. These traits should serve as useful selection criteria for species with the ability to resist water stress.

• 한국산림과학회지
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• 제99권5호
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• pp.711-719
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• 2010

We investigated physiological responses and phytoextraction ability of Pinus thunbergii in cadmium contaminated soil as part of our efforts in identifying plant materials for the restoration and revegetation of forest soil contaminated by heavy metals. Thirty seedlings (ten per treatment) were assigned to three treatments (control, 0.3 and 0.6 mM $CdSO_4$ solution) at first year experiment. At second year, ten seedlings per treatment treated with Cd during the first year experiment were divided by two groups (no Cd-treated and consecutive Cd-treated group). At first experiment, photosynthetic pigment content, and superoxide dismutase (SOD) and glutathione reductase (GR) activities have significantly reduced by Cd application, and the reduction rate was increased much higher as the rate of Cd application increased. On the other hand, thiol and malondialdehyde (MDA) content were significantly increased at the application of 0.6 mM of Cd. At the second year experiment, a general increase in chlorophyll and carotenoid content was observed with Cd treatment while SOD and GR activities showed a relative reduction compared to the control. Similar to the first year measurement, thiol and MDA contents also increased considerably due to Cd treatment. At harvest, dry matter was significantly reduced by Cd treatment especially at the rate of 0.6 mM Cd, but dry yield of P. thunbergii treated with 0.3 mM Cd was less affected and it was comparable with the control seedling. Cadmium concentration in seedling tissues increased with increasing Cd application rate while Cd uptake was higher in seedlings supplied with 0.3 mM Cd, which could be ascribed to their high dry matter. Overall, our study has demonstrated the unique physiological response of P. thunbergii to Cd-prolonged exposure by showing that the changes in photosynthetic pigment content and antioxidative enzyme activities were dependent on the concentration and duration of treatment. In addition, our results have demonstrated the potential of P. thunbergii to withstand up to 0.3 mM Cd (equivalent to cumulative Cd concentration of 134.4 to 268 mg $kg^{-1}$) without showing growth reduction, hence it might be used for phytoremediation of Cd contaminated areas.

• 한국산림과학회지
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• 제105권3호
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• pp.303-308
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• 2016

겨울철 제설제로 사용하는 염화칼슘에 의한 3년생 벚나무 잎의 가스교환 및 기공반응에 대해 알아보기 위해 개엽 전 염화칼슘 0.5%, 1.0%, 3.0% 수용액을 2회(1 L) 근권부에 처리하였다. 염화칼슘 처리 농도가 증가함에 따라 벚나무의 기공전도도($g_s$), 광합성율($P_n$), 증산율($T_r$), 그리고 수분이용효율(WUE)은 감소하였다. 염화칼슘 처리에 의해 기공전도도와 광합성율이 감소하였음에도 불구하고 엽육세포 내 $CO_2$ 농도($C_i$)가 대조구와 비슷하거나 높게 나타났다. 이러한 결과는 기공제한 뿐만 아니라 비기공제한 요인도 함께 광합성율의 감소를 야기하였다는 것을 의미한다. 한편, 벚나무의 개엽 전 염화칼슘 처리는 잎의 형태적 특징에도 영향을 주었다. 염분농도가 증가할수록 기공의 길이가 작아지고 기공밀도가 높게 나타났으며 잎의 크기가 작아졌는데, 이는 식물체 내 수분손실을 줄이기 위한 적응기작으로 판단된다.

• The Korean Journal of Ecology
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• 제26권4호
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• pp.165-172
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• 2003

The objectives of this study were to examine the physiological responses to ozone and to measure ozone uptake rates of Betula species exposed to relatively high concentration of pollutants. At the end of the growing season, photosynthesis, pigments contents, antioxidants (SOD and GR) and ozone uptake rates were measured or estimated at the leaves of five Betula species (Betula costata, B. davurica, B. platyphylla var. japonica, B. schmidtii and B. ermanii) exposed to 100ppb ozone concentration. On the termination of the experiment, growth effects were determined by measuring leaf area and dry weights of leaf, stem and root. Ozone treatment showed the significant reduction the leaf area and dry weight of four Betula species, except for B. ermanii. Shoot / root (SR) ratio of five species represented two different types. SR ratio of B. costata and B. davurica were lower than control, in contrast, SR ratio of B. platyphylla var. japonica, B. schimidtii and B. emani, were higher than that of control. The photosynthetic responses of five species were different in responses to ozone exposure. Four species, except for B. emanii, maintained or increased the stomatal conductance, but B. emanii decreased both stomatal conductance and photosynthesis. SOD activities of five species decreased by the ozone exposure, especially B. ermanii showed the largest reduction, GR activities of B. platyphylla var. japonica and B. schmidtii increased, B. costata and B. emanii decreased. Instantaneous ozone uptake rate was the highest at the leaves of B. ermanii and B. costata, ozone uptake per seedling was the highest at the leaf of B. schmidtii and B. emanii. It was concluded that B. costata, B. davurica and B. platyphylla var. japonica, appeared the growth reduction and visible ozone injury, were sensitive species to ozone, and B. schmidtii with the increased antioxidant activity and B. ermanii without the growth reduction were relatively resistant species to high ozone concentration at the early growing stage.

• 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.

• 생물환경조절학회지
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• 제21권2호
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• pp.153-161
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• 2012

피음처리에 의한 고려엉겅퀴와 누룩치의 광합성 및 생장특성을 조사하기 위하여, 차광막을 이용하여 전광처리구(0%), 약피음처리구(45~55%), 중간피음처리구(65~75%), 강피음처리구(88~92%) 설치하고 엽록소함량, 엽록소 형광반응, 광합성 반응 등을 조사하였다. 고려엉겅퀴와 누룩치 모두 피음처리 수준에 따라 엽록소 함량과 엽록소형광반응, 순양자효율 등이 증가하여 빛의 흡수와 광합성 반응에 대한 효율을 높이는 내음성 적응 반응을 나타냈으며, 엽면적 SLA 역시 증가하여 부족한 광환경에서 수광량을 늘리기 위해 엽면적은 늘어나고, 엽두께는 얇아지는 형태적인 변화가 나타났다. 특히 전광처리구에서 총 엽록소 함량, 엽록소 형광반응, 순양자효율, 기공전도도 및 기공증산속도가 비교적 낮았으며, 이는 강한 광으로 광저해 현상이 일어나 광합성 능력이 저하되는 것으로 볼 수 있다. 고려엉겅퀴의 강피음 처리구는 엽록소 함량도 높으며, 엽면적이 늘어나고 엽두께는 얇아져 광을 수집하기 위한 형태적인 변화도 나타나고 있으나 광선요구도보다 적은 광 환경에서 계속 생장함으로서 엽육내 $CO_2$를 효율적으로 소비하지 못하고, 수분이용효율 역시 감소되어 광합성 능력을 점점 상실해 가는 것으로 생각된다. 또한 고려엉겅퀴는 약광처리구(전광의 45~55%)에서최대광합성속도와 순양자효율이 가장 높고, 기공개폐 반응과 광화학반응 효율이 비교적 높았으며, 누룩치는 처리구간의 차이는 크지 않지만, 중간피음처리구에서 최대광합성속도, 순양자수율, 기공개폐반응 및광화학효율이 가장 높은 것으로 나타났다. 따라서 적절한 피음처리를 통해 건전한 생육을 유도하기 위해서는 고려엉겅퀴의 경우 전광을 약 45~55% 차단하고, 누룩치는 약 65~75% 차단시킨 광환경이 효과적이라 생각된다.