• ALGAE
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• 제29권4호
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• pp.321-331
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• 2014

Vertebrata lanosa is an abundant and obligate red algal epiphyte of Ascophyllum nodosum that forms part of a complex and highly integrated symbiotic system that includes the ascomycete, Mycophycias ascophylli. As part of ongoing studies to resolve interactions among species in the symbiosis, we used pulse amplitude modulation fluorimetry of chlorophyll a fluorescence, from photosystem II (PSII), to measure the maximum quantum yield ($F_v/F_m$) of PSII [$QY(II)_{max}$] and relative photosynthetic electron transport rates (rETR), as a function of light intensity, in order to evaluate the photosynthetic capacity of the two algal symbionts in the field and in the laboratory under different treatments. Our primary question was 'Is the ecological integration of these species reflected in a corresponding physiological integration involving photosynthetic process?' In the laboratory we measured changes in $QY(II)_{max}$ in thalli of V. lanosa and A. nodosum over one week periods when maintained together in either attached or detached treatments or when maintained separated from each other. While the $QY(II)_{max}$ of PSII of A. nodosum remained high and showed no significant variation among treatments, V. lanosa showed decreasing performance in the following conditions: V. lanosa attached to A. nodosum, V. lanosa in the same culture, but not attached to A. nodosum, and V. lanosa alone. These results are consistent with observations in which rETR was reduced in V. lanosa maintained alone versus attached to A. nodosum. Values for $QY(II)_{max}$ in V. lanosa measured in the field in fully submerged thalli were similar to those measured in the laboratory when V. lanosa was attached to it obligate host A. nodosum. Our results provide evidence of a physiological association of the epiphyte and its host that reflects the known ecology.

• ALGAE
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• 제20권2호
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• pp.121-125
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• 2005

The modern integrated fish-seaweed mariculture has been tested to reduce the environmental impacts of an intensive fed culture. To obtain the best seaweed bioremediation performance, the effects of therapeutants used for fish disease control on the selected seaweed species should be considered. As a selected seaweed, Porphyra yezoensis was tested with six commercial antibiotics including erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, doxycycline, pefloxacin, and amoxicillin trihydrate under the batch incubation at a photon flux density of 10 $\mu$mol ${\cdot}m^{-2}\;{\cdot}\;s^{-1}$ at 15$^{\circ}C$. Among the tested commercial antibiotics, erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, and doxycycline showed decreases in Fv/Fm, the photochemical efficiency of photosystem II, with a dose-dependant and time-dependant manner. From the quenching analysis of chlorophyll fluorescence, three differential patterns were observed in the antibiotics-treated Porphyra: (1) high nonphotochemical quenching (NPQ) and low photochemical quenching (qP) in the cases of Erythromycin thiocyanate_B and amoxicillin trihydrate, (2) high NPQ and high qP in the case of pefloxacin and (3) low NPQ and low qP in the case of oxytetracycline. These results indicated that antibiotics affected in various ways on the photosynthetic apparatus, reflecting differential lesion sites of antibiotics. In addition, the rates of ammonium uptake also decreased with a decrease of Fv/Fm in P. yezoensis thalli treated with erythromycin thiocyanate_B and oxytetracycline. Therefore, the four antibiotics mentioned could affect the bioremediation capacity of the selected seaweed species in the integrated fish-seaweed mariculture system due to the decrease of photosynthetic activity and the simultaneous decrease of ammonium uptake.

• 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.

• 한국산림과학회지
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• 제88권2호
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• pp.221-228
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• 1999

사방오리나무(Alnus firma)가 공해에 대해서 내성을 가지는 이유를 구명하기 위해서 광합성 등 생리적인 특성과 몇 가지 antioxidant 관여 효소를 분석하였다. 이를 위해서 공단이 많은 오염지역(여천산업단지)에서도 잘 자라는 사방오리나무 개체목과 피해를 받은 개체목을 각각 선발하였다. 그리고 비교를 위해서 오염원이 거의 없는 청정지역(수원)에서도 비슷한 생장을 하고 있는 개체목을 각각 1997년도에 선발하였다. 광합성능력, 기공전도도, 증산량, 엽록소함량, Rubisco, Antioxidant 효소(Superoxide dismutase(SOD) 그리고 Glutathione reductase(GR))의 활성 모두, 오염지역에서 잘 자라며 가시적인 피해를 보이지 않는 개체목의 경우 가시적인 피해가 있는 개체의 경우보다 높은 것으로 조사되었다. 이는 오염물질로부터 자신을 보호하여 정상적인 생장을 유지하기 위한 생물학적인 보상(Biological compensation)을 하는 것이라고 추정된다.

• 한국약용작물학회지
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• 제28권6호
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• pp.412-420
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• 2020

Background: Measurement of chlorophyll fluorescence (CF) is useful for detection the ability of plants to tolerate environmental stresses such as drought, and excessive sunlight. Cnidium officinale Makino is highly sensitive to water stress and excessive sunlight. In this study, we evaluated the effect of soil water and shade treatment on the photosynthesis and leaf temperature change of C. officinale. Methods and Results: C. officinale was cultivated under uniform irrigation for 1 week drought stress (no watering) for 6 days. A significant decrease in CF was observed on the 5th day of withholding water (approximately 6% of soil water content) regardless of shading. Notably, the Rfd_lss parameter (CF decrease rates) with and without shade treatment was reduced by 73.1% and 56.5% respectively, at 6 days compared with those at the initial stage (0 day). The patterns of the degree of CF parameters corresponded to those of the soil water content and difference between leaf temperature (Ts) and air temperature (Ta). Meanwhile, CF parameters recovered to the 3 - 4 days levels after re-watering, while the soil water potential was completely restored. The suitable soil water content for C. officinale optimal growth was between -5 kPa and -10 kPa in this experiment. Conclusions: Lack of soil water in the cultivation of C. officinale, even with shading, decreased latent heat cooling through transpiration. As a result, heat dissipation declined, and the plant was subjected to drought stress. Soil water content plays a major role in photosynthesis and leaf temperature in C. officinale.

• 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.

• Journal of Photoscience
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• 제8권3_4호
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• pp.105-112
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• 2001

Susceptibility to low temperature photoinhibition in photosynthetic apparatus was compared among three cucumber cultivars, Gahachungjang (GH), Banbaekjijeo (BB) and Gaeryangsymji (GR). By chilling in the light for 6 h, a sustained decrease in the potential quantum yield (Fv/Fm) and the oxidizable P700 contents was observed, and the decrease was less in GH than in BB and GR. Although the difference was small, some $\Phi_{PSII}$ remained in GH after light-chilling for 6 h indicating that a few electrons can flow around photosystem II(PSII). As a consequence, the primary electron acceptor of PSII, $Q_{A}$, was reduced slowly and was not fully reduced after light-chilling for 6 h in GH. Although the amplitude was small, the development of NPQ was also faster in GH, indicating a higher capacity for non-photochemical energy dissipation. The relative fraction of a fast relaxing component of NPQ (qf) was higher in GH. After light-chilling for 5 h, the values of qf in BB and GR became much smaller than that in GH, indicating BB and GR suffered more significant uncoupling of ATPase and/or irreversible damages in PSII. When fluorescence induction transients were recorded after chilling, significant differences in quenching coefficients (qQ and qN) were observed among the three cultivars.

• 한국작물학회지
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• 제21권2호
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• pp.187-202
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• 1976

출수기전후 수도의 광합성능화과 생육상태의 차이가 건물생산과 수량구성요소에 미치는 영향을 구명하고 통일품종의 출수전 저장물질과 출수후 축적 물질이 현미수량을 구성함에 있어서 차지하는 의존도를 재배시기를 달리한 상태에서 조사한바 그 성적을 요약하면 다음과 같다. 1. 등숙기의 광합성능력은 품종간에 차이를 보여 광합성능력이 비교적 높은 품종군(만경, 농림 2002, 동산 38호 Kotominori)과 낮은 품종군(진흥 팔금 통일 금남풍)으로 구별되였으며 그중 진흥 Kotominori 양품종은 수전기에서 유숙기에걸쳐 광합성능력의 저하가 심하였으며 시비법의 차이에 의한 광합성능력의 변동도 큰편이였다. 2. 출수후 광합성능력과 엽신질소함량및 엽중비율(엽신건물중/전건물중)간에는 정의 상관이 인정되었으며 일본품종은 한국 품종에 비하여 그들간의 상관이 더욱 높고 엽신질소함량도 높았다. 3. 수전기로부터 유숙기까지의 근활력소장은 광합성능력 단백태질소함량과도 상호밀접하게 관계하여 수전기에서 유숙기에 걸쳐 근의 산화력이 높은 것은 이삭의 건물증가량을 많게하고 최종적으로는 수량에도 영향하는 것으로 추찰되였다. 4. 공시품종들의 출수전저장탄수화물량과 출수후 탄수화물생산량에 의한 현미구성비율은 출수전 저장 탄수화물에 의존도가 15~26%에 불과하고 나머지 74~85는 출수후 탄수화물 생산량에 의존하고 있다. 5. 수전기의 엽신질소함량과 주당 영화수와의 관계를보면 한국품종군과 일본품종군간에는 2계열의 정의 상관이 인정되었고 시비법 차이에 의한 $\textrm{m}^2$당 영화수는 한국품종군에서는 후기중점 시비구가 일본품종군에서는 기비중점 시비구가 많은 결과를 보여주었다. 6. 출수기를 전후한 건물중과 엽면적은 이앙기가 빠를수록 높은 수치를 보였으며 엽면적 엽량 공히 출수전 3주간에 있어서는 건물증가율과 정의 상관이 인정되여 동기간에 있어서의 건물증가율의 차이는 엽면적의 차에 의하여 직접규제되나 출수후등숙에 접어들면서 엽면적의 직접적인 지배성은 점차로 소실되어 감을 알수 있었다. 7. 현미구성에 있어 출수전 저장동화물질과 출수후 생산된 동화물질에 의존비율은 이앙기가 빠를수록 그리고 엽신 N함량이 많을수록 출수전 저장동화물질에 의존도가 높아 재배시기이동에 의한 환경조건변화로 통일품종의 등숙향상과 수량증대가 가능함을 뒷받침하여 주었다. 8. 8월 17일 출수기를 중심으로 그이전에 출수한 구에서는 저장기간중 일사량 및 일조시간이 많고 평균기온도 높은 양호한 기상조건하에서 경과하게되여 현미구성에 있어 출수전 저장동화물질에 의존도를 높일수 있었다고 본다. 9. 이상의 출수전후 집적량과 기상환경과의 상관을 맺어본 결과 출수전 동화물질 저장량과 출수전 3주간의 평균일사량 일조시수 평균기온과는 고도의 정의 상관이 있었다.

• The Korean Journal of Ecology
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• 제24권2호
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• pp.93-100
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• 2001

One-year-old cottonwood (Populus deltoides Bartr.) clones, which were classified as sensitive or tolerant, were exposed to 150 n1/1 ozone (O$_3$) over 8 days for 8 hours each day under glass chamber conditions with natural sunlight. The leaves of the sensitive clone had black stipple and bifacial necrosis after $O_3$ treatment. Photosynthesis and stomatal conductance were measured before, during, and after the $O_3$ treatment. The photosynthetic rates due to $O_3$ treatment were decreased 51 percent and 34 percent on the sensitive and tolerant clone, respectively. The stomatal conductance of the sensitive clone was more than 40 percent higher than that of the tolerant clone regardless of the $O_3$ treatment. As light intensity increased, the $O_3$ effect on photosynthesis was clear. Compared to the previous growth chamber studies, our natural light exposure system was able to maintain a stable photosynthetic responses of the control treatment throughout the fumigation period. In addition, changes in assimilation versus intercellular $CO_2$ concentration (A/C curves) showed that $O_3$ decreased the slope and asymptote of the curves for the sensitive clone. This indicates that $O_3$ decreases the biochemical capacity of photosynthesis on the sensitive clone. Chlorophyll contents and fluorescence of the two clones were analyzed to examine the $O_3$ effects on photosystem 11, but $O_3$ did not impact these variables on either clone. Although the tolerant clone did not show any foliar injury, we could not find any ecophysiological defensive responses to $O_3$ treated. Stomatal conductance of the tolerant clone was originally much lower than that of the sensitive one. Thus, the mechanisms of the tolerant clone in this system are to narrowly open stomata and efficiently maintain photosynthesis with a more durable biochemical apparatus of photosynthesis under $O_3$ stress. The sensitive clone has higher photosynthetic capacity and more efficient light reaction activity than the tolerant one under charcoal filtered condition, but is not as resilient under stress.

• 한국해양학회지:바다
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• 제4권3호
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• pp.237-245
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• 1999

다시마 포자체에서 일어나는 광합성의 계절변화를 이해하기 위해, 1996년 2월부터 7월까지 동남해안에 양성한 엽체들의 광합성과 호흡률을 현장과 일정한 수온 및 영양염 조건으로 실험실에서 매월 측정하였다. 현장에서 측정한 P-I 매개변수는 계절적으로 변화하였다. 광합성력($P_{max}$)은 3월에 6.64 mg $O_2{\cdot}gdw^{-1}{\cdot}h^{-1}$로 최대였고, 이후 지속적으로 감소하였다. 광합성 효율(${\alpha}$)은 0.026~0.106의 범위였고, 광합성력과 유사한 시간변화를 보였다. 호흡률의 시간변화는 광합성력의 변화와 유의한 상관을 가지지 않았다. 호흡률은 0.25~0.83 mg $O_2{\cdot}gdw^{-1}{\cdot}h^{-1}$의 범위였다. 현장에서 측정한 광합성력은 중량의 상대성장률과 높은 상관을 지니고 있어, 광합성력이 증가함에 따라 체내에서 축적되는 물질의 양 또한 증가함을 알수 있었다. 현장과 실험실에서 측정한 광합성력을 비교한 결과, 2월내 현장에서의 광합성력이 낮았던 것은 이 기간 중 낮은 수온에 의한 영향 때문이었고, 3월 이후에 광합성력이 점진적으로 감소하는 것은 엽체의 연령증가에 따라 엽체의 두께가 증가하였기 때문이었다.4월에 측정한 엽체의 크기별 광합성력은 엽체의 두께와 광합성률간에는 음의 상관이 있다는 것을 나타내었다.