• Animal cells and systems
• /
• 제3권3호
• /
• pp.247-252
• /
• 1999

The aim of this study was to characterize antipredator tactics of anurans and to evaluate the effectiveness of these tactics for predator avoidance in real confrontations. Two types of experiments were conducted. In one experiment, one predator and one prey were placed together for one hour in a small confined space (one-to-one interaction). In another experiment, one predator and several prey were placed together for one day in a large enclosure in a field (field-based interaction). The prey consisted of three anuran species, Rana nigromaculata, R. rugosa, and Bombina orientalls: a snake species, Rhabdophis tigrinus tigrinus, was used as a predator. Results of both experiments demonstrated a range in antipredator responses of the frogs, from toxicity and warning coloration, coupled with slow responses in Bombina to little (or only slight) toxicity, crypsis, and fast take-off responses to the predator in the ranids. oth ranid species exhibited lower survival(57%) than Bombina (95%) in the field-based interaction, suggesting that motor responses of the palatable prey due to attacks of the predator ultimately limited their survival. The jumping of the ranids increased the activity of the predator, which became more likely to strike. Simple crouching(seen in R. rugosa and B. orientalis) and chemical defense (in Bombina) reduced predatory attacks.

• Journal of Ecology and Environment
• /
• 제33권3호
• /
• pp.217-222
• /
• 2010

To determine whether or not the female Korean salamander, Hynobius leechii, responds to water currents and, if so, whether those responses depend on their reproductive conditions, we evaluated the responses of ovulated and oviposited females to 1-Hz water currents generated by a model salamander with and without the placement of a transparent water current blocker between the model and the test females. The ovulated females responded to water currents by turning their heads toward, approaching, and/or making physical contact with the model. When the water current blocker was in place, the number of salamanders that approached the model was reduced significantly. The approaching and touching responses of ovulated females were greater than those of oviposited females, whereas the other measurements evidenced no differences. None of the responses of the oviposited females to water currents was affected by the presence of the blocker. Our results indicate that female H. leechii responds to water currents via a mechanosensory system.

• Journal of Microbiology and Biotechnology
• /
• 제17권9호
• /
• pp.1504-1512
• /
• 2007

The fpr gene, which encodes a ferredoxin-$NADP^+$ reductase, is known to participate in the reversible redox reactions between $NADP^+$/NADPH and electron carriers, such as ferredoxin or flavodoxin. The role of Fpr and its regulatory protein, FinR, in Pseudomonas putida KT2440 on the oxidative and osmotic stress responses has already been characterized [Lee at al. (2006). Biochem. Biophys. Res. Commun. 339, 1246-1254]. In the genome of P. putida KT2440, another Fpr homolog (FprB) has a 35.3% amino acid identity with Fpr. The fprB gene was cloned and expressed in Escherichia coli. The diaphorase activity assay was conducted using purified FprB to identify the function of FprB. In contrast to the fpr gene, the induction of fprB was not affected by oxidative stress agents, such as paraquat, menadione, $H_2O_2$, and t-butyl hydroperoxide. However, a higher level of fprB induction was observed under osmotic stress. Targeted disruption of fprB by homologous recombination resulted in a growth defect under high osmotic conditions. Recovery of oxidatively damaged aconitase activity was faster for the fprB mutant than for the fpr mutant, yet still slower than that for the wild type. Therefore, these data suggest that the catalytic function of FprB may have evolved to augment the function of Fpr in P. putida KT2440.

• Journal of Forest and Environmental Science
• /
• 제38권4호
• /
• pp.229-238
• /
• 2022

Q. mongolica and Q. dentata are representative species of deciduous forest communities in Korea and are known to be relatively resistant to soil drying condition among Korean oaks. This study attempted to elucidate the degree of competition and ecological niche characteristics of the two species by comparing the ecological responses of the two species according to soil moisture. Competition between Q. mongolica and Q. dentata was shown to be more intense under the conditions where moisture content was low than under the conditions where moisture content was high. As for the ecological niche overlaps of the two species for soil moisture, the structural traits of plant such as stem diameter overlapped the most, the traits of biomass such as petiole weight overlapped the least, and photosynthetic organ-related traits such as leaf width and length overlapped intermediately. When looking at the competition for soil moisture between the two species, it can be seen that Q. mongolica won in nine traits (leaf width length, leaf lamina length, leaf lamina weight, leaf petiole weight, leaf area, leaves weight, shoot weight, root weight, and plant weight) and Q. dentata won in the remaining seven traits (leaf petiole length, leaves number, stem length, stem diameter, stem weight, shoot length, and root length). Competition between the two species for the moisture environment of the soil was shown to be intense under the conditions where moisture content was low. The degree of competition between Q. dentata and Q. mongolica for soil moisture is high under the conditions where soil moisture content is low, and it is judged that Q. mongolica is more competitive for soil moisture than Q. dentata.

• The Korean Journal of Ecology
• /
• 제6권3호
• /
• pp.153-166
• /
• 1983

The distribution of beech species (Fagus) and beech-dominated forests along climatic gradients in the Northern Hemisphere was studied by use of taxonomic and ecological literature. The genus Fagus as a whole occurs over the range of 4.5 to 20.0。C mean annual temperature and 600 to 1000 mm in lower limit, mean annual precipitation. At the higher end of the temperature range, beech occurs in zones with relatively high growing-season precipitation. Edaphically, beech species and beech-dominated forests tend to occur on mesic, moderately fertile sites. Beech-dominated forests occur in a limited portion of the climatic range of the genus with sensitive responses to other environmental factors. The distributional range of beech-dominated forests on a global scale depends more on climatic factors and geological events than on soil conditions or other factors, summarizing the facts obtained by many researchers on beech dominated forests.

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

• 한국환경생태학회지
• /
• 제32권3호
• /
• pp.332-341
• /
• 2018

본 연구는 2018년에 개장될 대구광역시 달성습지 생태학습관의 가치적 이용 및 경쟁력 있는 운영을 위해 달성습지 생태학습관의 특성에 맞는 운영방안을 제시하는 것이 목적이다. 이를 위해, 운영방법, 자원봉사자, 예산 및 수익 등 22개의 설문항목을 이용해 전국 77개 생태학습기관 담당자를 대상으로 설문조사를 실시하였다. 그 중 50개 생태학습기관(Type A)에서 응답을 하였으며, 그 중 달성습지 생태학습관과 비슷한 규모의 12개 생태학습기관(Type B)을 추출하여 추가 분석을 실시하였다. 설문에 대한 결과로 달성습지 생태학습관은 대구광역시에서 직접 운영을 하는 것이 적합하며, 최소 3-5명의 운영인력이 필요한 것으로 조사되었다. 정기적으로 활동하는 자원봉사자는 25-30명 내외의 인원이 필요하다. 인건비를 제외한 연간 운영 예산을 분석한 결과 대구광역시에 의해 직접운영 될 경우, 1억 5천만원 이상 2억원 미만이 필요하다. 본 연구는 국내 생태학습관 담당자를 대상으로 한 설문조사를 바탕으로 달성습지 생태학습관에 대해 객관적이며 상세한 운영방안을 수립할 기초자료를 마련했다는데 의의가 있다.

• 한국조경학회지
• /
• 제36권2호
• /
• pp.53-59
• /
• 2008

도시가 산업화 되어가면서 도심의 토지이용이 과밀화되고 건축물의 면적이 늘어나고 있다. 이에 건축물 녹화가 옥상 및 벽면을 중심으로 적극적으로 조성되고 있으며, 입면녹화의 경우 건물이 고층화 되면서 입면적이 넓어 벽면녹화가 도심에서 효과적인 녹화수단으로 인식되고 있다. 특히 패널타입의 녹화수법은 조기 녹화와 설치 시공의 편리함으로 점차 이용이 증가하고 있다. 그러나 패널타입에 대 한 연구는 대부분 식생 하부 시스템이나 관수시스템을 중심으로 이루어지고 있으며, 경관 중심에 대한 연구는 전무한 실정이다. 이에 본 연구에서는 패널형 입면녹화의 경관평가를 통하여 선호요소를 추출하고자 한다. 설문은 패널형 입면녹화가 설치된 장소의 이용자들을 중심으로 직접조사를 하였다 연구 결과, 자연스럽다는 형용사에서 3.80으로 가장 높은 점수를 나타났다. 이는 옹벽이나 건축물 벽면이 드러나는 것보다 녹화를 하는 것이 이용자들에게 긍정적인 반응을 보이는 것으로 사료된다. 다음으로 친근한(3.70), 편안한(3.65), 아름다운(3.65), 안정감 있는(3.50)가 긍정적인 경관이미지로 나타났다. 반면 정적인, 적막한, 소박한, 무거운, 우중충한, 어두운, 지저분한의 부정적 경관 이미지가 나타났는데, 이는 관리가 제대로 이루어지지 않기 때문으로 사료된다. 이러한 연구 결과를 통하여 패널형 입면녹화의 개발과 보급에 필요한 기초자료로 활용하고자 한다.

• Asian Journal of Atmospheric Environment
• /
• 제6권3호
• /
• pp.192-205
• /
• 2012

The effects on birch (Betula spp.) of elevated carbon dioxide ($CO_2$) and ozone ($O_3$), which are both increasing in the troposphere, are surveyed in detail based on the literature. Birches establish themselves in the open field after disturbances, and then become dominant trees in temperate or boreal forests. Ecophysiological approaches include the measurement of photosynthesis, biomass, growth, and survival of seedlings and trees. Elevated $CO_2$ levels give rise to a net enhancement of the growth of birch trees, whereas high $O_3$ generally reduces growth. Although the effects of the two are opposed, there is also an interactive effect. Basic physiological responses of the single genus Betula to $CO_2$ and $O_3$ are set out, and some data are summarized regarding ecological interactions between trees, or between trees and other organisms.

• KIEAE Journal
• /
• 제4권4호
• /
• pp.27-34
• /
• 2004

As number of new housing construction has been growing, the increasing number of people experiencing from Sick Building Syndrome (SBS) is distinct. The purpose of this study is to examine the symptoms reported by residents responses to cope with the syndrome and to investigate their environmental characteristics considered relevant to the syndrome. Respondents were housewives living in apartments and were more likely to stay at home. 170 data were collected by both web-based internet survey and conventional questionnaire survey. The findings revealed that the symptom appeared very diverse and composite. The most common symptom was eye irritation. Among diverse coping behaviors, ventilation was most popular.