• 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.

• Journal of Ecology and Environment
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• 제33권3호
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• pp.253-260
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• 2010

It has been well established that leaf longevity is linked to the carbon economy of plants. We used this relationship to predict leaf lifetime carbon gains from leaf lifespan, and estimated the gross primary production (GPP) of a young deciduous forest of Japanese beech (Fagus crenata) located in central Japan. The light-saturated photosynthetic rates of the leaves were measured repeatedly during the growing season. We used the leaf lifespan to calculate the conversion coefficient from the light-saturated photosynthetic rate into the realized leaf lifetime carbon gain under field conditions. The leaf turnover rate was estimated using litter traps. GPP was estimated as the product of lifetime carbon gain per unit of leaf mass, and the annual leaf turnover rate. The GPP of the forest in 2007 was estimated to be $1.2{\times}10^3gCm^{-2}y^{-1}$, which was within the range of previously reported GPP values of beech forests in Japan, and was close to the GPP of a European beech forest, as estimated by eddy flux measurements.

• 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.

• Journal of Crop Science and Biotechnology
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• 제11권1호
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• pp.75-82
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• 2008

Functional stay-green is a beneficial trait that may increase grain yield through the sustained photosynthetic competence during monocarpic senescence in cereal crops. The temporal changes of photosynthesis and related characteristics throughout the grain filling period of a stay-green japonica rice "SNU-SG1" was compared in growth chamber conditions with three high-yielding cultivars(HYVs) and their $F_1$ hybrids with SNU-SG1. SNU-SG1 exhibited a typical characteristic of functional stay-green in terms of chlorophyll degradation and photosynthetic competence during grain filling. According to the photosynthesis-light response curve measured at 10 and 35 d after heading for the flag leaf, SNU-SG1 exhibited higher initial light conversion efficiency and thus higher gross photosynthetic rate at light saturation compared to HYVs. Light saturation point was not different among genotypes, ranging from 1000 to 1500 ${\mu}mol$ photon $m^{-2}s^{-1}$. Net photosynthetic rate at light saturation($P_{max}$) of the upper four leaves in SNU-SG1 was much higher and sustained longer throughout grain-filling than HYVs and $F_1$ hybrids. The sustained high photosynthetic competence of SNU-SG1 during grain filling was ascribed to the longer maintenance of high mesophyll conductance that resulted from not only high chlorophyll content and its delayed degradation but also the slow degeneration of photosystem II(PS II) as judged by chlorophyll fluorescence($F_v/F_m$) of flag leaves. $F_1$ hybrids showed slow degeneration of photosystem II similar to the male parent SNU-SG1 while chlorophyll degradation pattern close to female parents, thus exhibiting a little higher $P_{max}$ than female parents. These results suggest that SNU-SG1 has a typical functional stay-green trait that can be utilized for increasing rice yield potential through the improved dry matter production during grain filling.

• ALGAE
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• 제28권4호
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• pp.355-363
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• 2013

The coralline alga, Corallina officinalis, is a widely distributed intertidal species in temperate coastal regions. It is usually exposed to high fluctuations of light intensity, light quality, temperature, and desiccation, all of which affect the temporal and spatial distribution as well as the morphology and the metabolism of this alga. In laboratory experiments we examined the effects of different light intensities (50, 100, and 200 ${\mu}mol$ photons $m^{-2}s^{-1}$) on photosynthesis, calcification, photosynthetic pigment contents (chlorophyll a and carotenoids), and growth rate of C. officinalis to clarify its photoacclimation strategies. Net photosynthesis, calcification and dissolution rates based on weight were not sensitive to irradiance. Although, photosynthesis and calcification did not clearly respond to light intensity, photosynthetic pigment contents were significantly lower at higher light intensities. In addition, higher irradiances induced significant enhancement of gross photosynthesis based on chlorophyll a. As a result, the specific growth rate was significantly stimulated by high light intensity. Our results suggest that photoacclimation of C. officinalis to different light conditions may be regulated to optimize growth.

• 생물환경조절학회지
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• 제9권4호
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• pp.185-192
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• 2000

본연구는 시설내 다양한 환경조건하에서 오이의 호흡속도에 관한 수리적 모형을 개발하고자 실시하였다. 개개 오이 식물에 대한 총광합성속도의 8.55%가 호흡에 사용되었다. 생장호흡계수는 0.0935로 추정되었고 유지호흡속도는 24$^{\circ}C$ 온도에서 0.00158g C$H_2O$.g$^{-1}$.h$^{-1}$로 추정되었다. 그리고 그것은 온도상승에 따라 지수적으로 증가하였다. 호흡속도는 저장 탄수화물량이 낮아짐에 따라 비례적으로 감소했고 뿌리의 이온흡수호흡속도는 0.6648g C$H_2O$.(gN)$^{-1}$로 추정되었다.

• 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.

• 한국해양학회지:바다
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• 제29권1호
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• pp.28-41
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• 2024

탄소수지는 다양한 환경조건에서 식물의 생리적 상태를 평가할 수 있는 중요한 지표 중 하나이다. 우리 동해 연안에 분포하는 새우말의 수온 변화(5-30℃)에 따른 광합성률과 호흡률을 측정하여, 전체 식물 탄소수지의 계절적 변동을 추정하였다. 수온 처리에 따라 최대총광합성률은 유의한 차이를 보였지만, 광합성 효율은 유의한 차이를 보이지 않았다. 새우말의 최대총광합성률은 수온이 상승함에 따라 증가하여 20℃에서 최대값(101.65 μmol O₂ g^-1 DW h^-1)을 보인 후 30℃에서 급격히 감소하였다. 수온 변화에 따른 새우말의 포화광도, 보상광도와 호흡률은 모두 유의한 차이를 보였다. 새우말의 포화광도는 20-25℃까지(121.59-124.50 μmol photons m^-2 s^-1) 증가하다가 30℃에서 급격히 감소하였다. 보상광도와 호흡률은 수온이 증가할수록 점차 증가하였다. 최대총광합성률과 호흡률의 비율은 5℃에서 가장 높았고, 30℃에서 급격히 감소하였다. 광합성 매개변수, 호흡률 및 생체량을 통해서 추정된 새우말 전체 식물의 탄소수지는 겨울과 봄에 증가하고, 여름과 가을에 감소하는 뚜렷한 계절적 경향을 보였으며, 봄에 생장이 가장 활발하고, 수온이 가장 높은 시기에 급격히 감소하는 새우말의 생장 패턴과 일치하였다. 새우말은 늦여름부터 겨울까지 음의 탄소수지를, 봄에서 초여름까지 양의 탄소수지를 보였다. 기후 변화에 의한 지속적인 수온 상승은 우리 동해 연안 암반생태계에 분포하는 잘피생육지의 구조와 기능에 영향을 미칠 것으로 판단된다.

• Journal of Plant Biology
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• 제14권4호
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• pp.19-26
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• 1971

The sample stand of Pinus rigida plantation was chosen from those at the Choongnam Forest Experiment Station, Choongnam. The diameter at breast height (D) and the height of tree (H) of each tree in the sample plot of 200$m^2$ were measured yearly a from 1967 through 1969. The stand was 12.7-13.4cm in mean diameter and had a stand density of 2,150 trees per ha. The trunk, branches and leaves of each sample tree were separately weighed according to the stratified clip technique. The allometric relation between D2H and dry weight of trunk (Ws), branches (Wb) and leaves (Wl) were approximated by $$W_s=0.05917 (D^2H)^{0.837}$$ $$W_0=0.00655 (D^2H)^{0.989 }$$ $$W_l=0.04466(D^2H)^{0.690}$$ From the above, the standing crops in the sample stand was estimated to be as much as 76.7, 81.7 and 88.2 tons of dry matter, above ground, per ha in 1967, 1968 and 1969, respectively. Annual net production, as the sum of the biomass newly produced during one year, was estimated at 4.97-5.47 tons per ha per year. The respiratory and the photosynthetic rate deduced from theoretical calculations were 0.045 and 0.74kg of dry matter per kg per year. Tentative estimate of annual respiratory loss was made and annual gross production was roughly estimated at 4.4-4.7 and 10.7-12.9 tons of dry matter per ha per year. The ratio of respiratory loss to gross production was approximately 36-41:1.

• The Korean Journal of Ecology
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• 제11권1호
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• pp.1-15
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• 1988

Studies on species compostion, promary production of benthic algal assemblage were carried out along a channel of the salt marsh near Inch'on, Kyonggi Bay, Korea. Possible biological, physical and KDICical factors controlling the aglal assemblage were also examined. The oveall diatoms were encountered one hundred and thirty-seven taxa, of which the dominant species were Paralia sulcata and Cymatosira belgica. These two species accounted for 32.6% relative abundance throughout the study period. Diatom taxa had no clear seasonal pattern in abundance analysis. But at the algal blooming period in spring, euglenoids occurred with a high abundance. The chlorophyll a content of benthic algae showed definite seasonal pattern. The algal biomass of the appeared to influence the spatial fluctuation in the algal biomass of the channel was regulated primarily by water content of sediment. Grazing by zoobenthos apperaed to influence the spatial fluctuation in the algal biomass of the sediment surface. The algal photosynthesis was measured in the laboratory with oxygen method. Photo-synthetic rate was independent of the temperature under the lower irradiance. The gross production from March to November was estimated to be 190g C/m2 at the channel slope. Photosynthetic efficiency was 0.37% on the basis of the photosyntherically active radiation for the study period.