• 대한환경공학회지
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• 제31권10호
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• pp.893-900
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• 2009

시화호 인공습지의 유기물생산에 대한 갈대부착조류의 기여도를 평가하기 위하여 유입수의 수질특성이 다른 두 습지(반월천습지와 동화천습지)에서 4월부터 10월까지 매월 부착조류의 1차생산력을 측정하였다. 부착조류의 현존량은 반월천습지와 동화천습지에서 각각 37~3,581 mgChl.a/$m^2$surface stem(평균 655 mgChl.a/$m^2$surface stem), 87~2,093 mgChl.a/$m^2$surface stem(평균 527 mgChl.a/$m^2$surface stem)의 범위로 동화천습지에 비해 반월천습지에서 큰 값을 보였다. 반면 부착조류의 광합성효율을 나타내는 동화계수(assimilation number; AN)는 반월천습지에 비해 TN/TP 비가 작은 동화천습지에서 높았다. 두 습지로 유입되는 유입수의 TN/TP비와 AN사이에서의 음의 상관(r=0.46)으로부터 부착조류의 높은 광합성효율은 낮은 TN/TP와 관련이 있는 것으로 사료된다. 부착조류의 단위면적당 일일 1차생산력은 반월천습지에서 307~2,473 mgC/$m^2$/day, 동화천습지에서 756~2,096 mgC/$m^2$/day로 두 습지 모두 여름에 높은 값을 보였다. 두 습지의 평균 1차생산력은 반월천습지가 부착조류의 현존량이 큼에도 불구하고 1,166 mgC/$m^2$/day으로 동화천습지(1,467 mgC/$m^2$/day)에 비해 낮았다. 이는 AN 값에서 알 수 있듯이 반월천습지의 광합성효율이 동화천습지에 비해 낮았기 때문으로 판단된다. 시화호 인공습지에서 갈대부착조류에 의한 연간 총 유기물생산은 300 tonC/year(습지 전체 유기물생산의 33%)로 습지내 유기물생산에 부착조류의 기여가 큰 것으로 나타났다. 습지내 과도한 유기물생산은 습지의 수처리효율을 저하시킬 수 있으므로 수처리용 인공습지의 관리에 있어서 갈대부착조류의 역할이 고려되어야 한다.

• 생물환경조절학회지
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• 제4권2호
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• pp.175-180
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• 1995

본 연구는 SCDS(specific color difference sensor)를 이용하여 토마토의 비파괴적인 질소 영양 진단 방법을 확립하기 위하여 질소 농도를 0, 10, 50, 100, 150, 200, 300, 600ppm으로 조절하여 NFT방식으로 실험을 수행하였으며 그 결과를 요약하면 다음과 같다. 배양액 내의 질소 농도가 0ppm에서 150ppm으로 높아짐에 따라 토마토 잎의 기공 저항은 급격히 줄어든 반면 기공 확산 속도는 증가하였다. 한편, 질소 농도가 높아짐에 따라 광합성 속도도 증가하였지만 100ppm에서 부터 600ppm까지는 큰 차이를 보이지 않았다. 토마토 잎의 SCDS값이 높아짐에 따라 광합성 속도는 직선적으로 증가하였으며 평균 과중과 상품 수량은 2차 곡선모양으로 증가하는 경향을 보였다. 엽내 질소 함량이 3% 정도될 때까지 광합성 속도는 크게 증가하였지만 3.3-3.5% 수준부터 광합성은 포화상태를 나타냈다. 토마토 잎의 SCDS값과 엽내 질소 함량 간에는 고도로 유의한 정의 상관을 보였다. 토마토의 생리적 활성, 생육 및 상품 수량을 고려해 볼 때, 엽내 질소 함량의 적정 범위는 3.0-3.8%인 것으로 나타났다. 이 범위에 해당되는 SCDS값은 40.4-52.2였다.

• 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.

• Journal of Ecology and Environment
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• 제31권3호
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• pp.193-200
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• 2008

We obtained quantitative information on leaf unfolding and leaf shedding by observing 45 species of cool temperate deciduous trees in an arboretum over 5 growing seasons. These trees were in leaf (the foliage period) for 207 days on average after 1 April; 50% of leaves had been shed by 192 days after 1 April. Duration from the start of leaf unfolding to 50% leaf shedding was 157 days on average. Leaf unfolding began 35 days on average after 1 April. For leaf unfolding to begin, a$ 51^{\circ}C{\cdot}day$ of cumulated daily mean air temperature above $5^{\circ}C$ from 1 January (modified Kira's warmth index) was needed. Fifty-nine days elapsed between initiation and the final stage of leaf unfolding. The period of net photosynthetic assimilation was 157 days. The species with succeeding- type leaf unfolding associated with the anemochore seed type dominated the early stage of succession, while the species with flush-type leaf unfolding tended to dominate the late stage of succession. Few species were found in regions where late frosts occur after the day when the cumulative temperature for leaf unfolding is achieved. Biological characteristics include time of leaf unfolding, which affects the life history of each species, so that each species occupies its own niche in the stand. We conclude that that leaf phenology, such as timing of leaf unfolding and leaf shedding, is one of the components of each species' ecological characteristics.

• 한국초지조사료학회지
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• 제3권2호
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• pp.77-85
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• 1983

본(本) 보고(報告)는 광합성(光合成)의 동력학(動力學)에 관하여 연구(硏究)한 결과(結果)이며 더욱 동력학식(動力學式)의 타당성과 확실성(確實性)을 해바라기의 광합성실험(光合成實驗)으로 구명(究明)되었다. 광합성(光合成)의 동력학식(動力學式)은 물질(物質)의 동화작용(同化作用)과 이화작용(異化作用)의 수식화(數式化)로 부터 유도되었으며 그 결과(結果)는(6), (7)식(式)과 같다. 한편 해바라기를 재료(材料)로 한 제환경조건(諸環境條件)에 관계하는 광합성실험(光合成實驗) 결과(結果)로 얻어진 (8)식(式)에 의하여 동력학식(動力學式)에 대한 타당성이 입증되었다.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1996년도 식물학심포지움 식물호르몬과 신호전달
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• pp.50-63
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• 1996

Nitrogen (N) is an important regulator of the expression of genes involved in carbon and N assimilation pathways in plants by selectively altering the levels of proteins and/or mRNAs. These in C4 plants include genes for such as phosphoenolpyruvate carboxylase, carbonic anhydrase, and pyruvate-Pi dikinase. The C4 genes are regulated in mesophyll cells by N availability both transcriptionally and posttranscriptionally through cytokinins and glutamine as signals. The level of both the signals is up-regulated by N availability: cytokinins in roots and glutamine in leaves. The level of glutamine is controlled by the differential expression by N of glutamine synthetase and ferrdoxin-dependent glutamate synthase genes which locate in the mesophyll cells of C4 plants. The results is discussed as molecular mechanism for the greater N use efficiency of the plants as well as N partitioning is the photosynthetic cells.

• ALGAE
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• 제37권4호
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• pp.265-279
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• 2022

The primary production (PP) by phytoplankton in marine ecosystems is essential for carbon cycling and fueling food webs. Hence, estimating the PP in the territorial sea of each country is a necessary step to achieving carbon neutrality. To estimate the PP in the territorial sea of the Republic of Korea from 2005 to 2021, we analyzed various physiochemical parameters, such as sea surface temperature (SST), Secchi depth, and concentrations of chlorophyll-a and nutrients in the seas of five regions, including the East Sea, West Sea, western South Sea, eastern South Sea, and the waters off Jeju Island. During the 17-year study period, the SST tended to increase, while the nutrient concentrations declined, except in the Jeju area. Overall, the PP did not show a specific temporal trend, but daily PP in the western South Sea was the highest among the five regions. Moreover, the maximum PP in the Korean territorial waters (76,450 km²) was estimated at 11,227 Gg C y^-1, which accounts for 0.03% of the global PP. The results may give insights into a better understanding of the PP, further resource utilization, and environmental sustainability in the studied region.

• 생태와환경
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• 제40권1호
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• pp.61-71
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• 2007

본 연구는 국내 최대의 수질정화용 인공습지인 시화호 인공습지의 개방수역(open water)에서 식물플랑크톤에 의한 광합성특성 및 유기물생산력을 조사 평가하여 효율적인 습지관리를 위해 open water관리방안의 기초자료를 제공하기 위함이다. 식물플랑크톤의 광합성특성 및 1차 생산력은 유입수의 수질특성과 체류시간이 다른 반월천습지와 동화천습지의 open water에서 조사되었다. 조사기간 동안 시화호 인공습지내 5개 open water에서 식물플랑크톤에 의한 1차 생산력은 $481{\sim}11,275mgC\;m^{-2}\;day^{-1}$의 범위로 연중 부영양화 수준을 보였고 계절과 지점에 따라 변동이 컸다. 시화호 인공습지에서 식물플랑크톤의 P-I curve 모델계수를 통한 광합성특성은 두 습지로 유입되는 유입수의 상반되는 수질특성(인과 질소 농도)에 크게 영향을 받는 것으로 나타났다. 최대광합성속도 (Pmax)는 $42{\times}1,014 mgC\;m^{-3}\;hr^{-1}$로 chi. ${\alpha}$ 농도와 양의 상관(R=0.47)을 보였다. 식물플랑크톤의 광합성효율을 나타내는 동화계수(AN)두 습지 모두 고습지와 저습지의 AN값의 차이를 보이지 않았지만 동화천습지의 AN값이 평균 8.5gC $gChl^{-1}\;hr^{-1}$로 반월천습지의 평균 5.8gC $gChl^{-1}\;hr^{-1}$보다 높은 값을 보여 인 농도가 높은 동화천습지에서 식물플랑크톤의 광합성효율이 큰 것으로 나타났다. 두 하천의 수질특성으로부터 식물플랑크톤의 광합성효율은 질소보다 인 농도 그리고 작은 TN/TP와 관련이 있는 것으로 사료된다. 낮은 광도에 대한 광합성능력을 나타내는 초기기울기와 동화계수 사이에는 높은 양의 상관(R=0.81)을 보인 것으로 보아, 낮은 광조건에서 광합성능력이 큰 식물플랑크톤이 광합성효율도 큰 것으로 나타났다. 본 연구에서 시화호 인공습지의 open water에서 식물플랑크톤에 의한 유기물생산이 매우 높은 것으로 보아 식물플랑크톤이 습지의 수질 및 수처리효율에 영향을 미칠 것을 판단된다. 습지의 수처리효율을 향상시키기 위해서는 체류시간을 짧게 해주거나 open water의 면적을 줄여 식물플랑크톤의 증식을 억제하거나 또는 증식한 식물플랑크톤이 습지외부로 유출되지 않도록 하는 관리방안이 필요할 것으로 본다.

• 한국토양비료학회지
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• 제46권6호
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• pp.659-664
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• 2013

The aim of this study is to determine the drought stress index through photochemical analysis in red pepper (Capsiumannuum L.). The photochemical interpretation was performed in the basis of the relation between Kautsky effect and Photosystem II (PSII) following the measurement of chlorophyll, pheophytin contents, and $CO_2$ assimilation in drought stressed 5-week-old red pepper plants. The $CO_2$ assimilation rate was severely lowered with almost 77% reduction of chlorophyll and pheophytin contents at four days after non-irrigation. It was clearly observed that the chlorophyll fluorescence intensity rose from a minimum level (the O level), in less than one second, to a maximum level (the P-level) via two intermediate steps labeled J and I (OJIP process). Drought factor index (DFI) was also calculated using measured OJIP parameters. The DFI was -0.22, meaning not only the initial inhibition of PSII but also sequential inhibition of PSI. In real, most of all photochemical parameters such as quantum yield of the electron transport flux from Quinone A ($Q_A$) to Quinone B ($Q_B$), quantum yield of the electron transport flux until the PSI electron acceptors, quantum yield of the electron transport flux until the PSI electron acceptors, average absorbed photon flux per PSII reaction center, and electron transport flux until PSI acceptors per cross section were profoundly reduced except number of QA reducing reaction centers (RCs) per PSII antenna chlorophyll (RC/ABS). It was illuminated that at least 6 parameters related with quantum yield/efficiency and specific energy fluxes (per active PSII RC) could be applied to be used as the drought stress index. Furthermore, in the combination of parameters, driving forces (DF) for photochemical activity could be deduced from the performance index (PI) for energy conservation from photons absorbed by PSII antenna until the reduction of PSI acceptors. In conclusion, photochemical responses and their related parameters can be used as physiological DFI.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.227-227
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• 2017

This study was conducted to analyze the reduction of quality and ripening rate of rice due to submergence during ripening stage and identify the physiological cause. Korean japonica type rice cultivars, Nampyeong was used in the experiment. The following 7, 14 day after heading, they were then moved into submergence treatment facility and we conducted the tests under three different submergence conditions - T1(clear water and overhead submergence), T2(Muddy water and exposure of Flag leaf end ), T3(Muddy water and overhead submergence), and the treatment lasted for 4days. The decrease of ripening rate was most severe in T3 treatment at 7days after heading, and the decrease of head rice ratio was most severe in T3 treatment at 14days after heading. Meanwhile the starch synthesis was inhibited, as the supply of assimilation products was inhibited in grain during the submergence treatment. And in stem, sucrose content was increased because the soluble carbohydrates accumulated before heading were decomposed. These changes may be due to the consumption of respiratory substrate in anaerobic conditions and the inhibition of the production of photosynthetic products by light interception. In order to see what kind of reaction occurs at the molecular level, we examined the degree of RNA expression in grain, stem and leaf. First, the expression of rna associated with starch synthesis in grain was decreased in all submergence treatment. and especially Ospul(DBE) was more decreased in 14days after heading treatment than 7days after heading treatment. This difference can explain the result that the decrease of head rice ratio was more severe at 14days after heading. And in stem, the expression of rna associated with the supply of assimilation products was decreased in submergence treatment. Finally in leaf, the expression of rna(ADH, ALDH) associated with anaerobic respiration was increased, while the expression of rna associated with photosynthesis was decreased. These results of physiological analysis can used to develop the cultivation technique and to offer the information for breeding the cultivars with tolerant characteristics to submergence stress during ripening stage in rice.