• Korean Journal of Environmental Biology
• /
• v.23 no.2 s.58
• /
• pp.157-162
• /
• 2005

To clarify the key characteristics of Korean brown frogs (R. dybowskii, R. huanrenesis and R. amurensis coreana), this study employed a morphological and morphometrical comparisons among brown frogs found in Korea and Japanese endemic species, R. tsushimensis. As a result, it was considered that the key characteristics were the shape of the finger and toe tips, the markings of the lower jaw, the presence or absence of an upper lip line, the development of toe webbing, and the shape of the vomerine teeth series by morphological comparisons of brown frogs. Also, there were significant differences in tympanum diameters and foot lengths of the four species of brown frogs. Therefore, a comparison between morphological and morphometric characters is an effective way to clarify the identification of brown frogs.

• Korean Journal of Environmental Biology
• /
• v.21 no.1
• /
• pp.45-51
• /
• 2003

Genetic diversity of local populations among geologically isolated groups of Rana amurensis was refined by sequence comparison of the mitochondrial (mt) 165 rDNA genes. Each 401 base pairs of DNA sequences, which was determined from four local populations of Rana amurensis, two local populations of R. nigromacutata, and three species of the genus Rana were used in this analysis. Despite morphological similarity of Rana amurensis, Korean populations were well distinguished from the other groups on the basis of 105 rDNA gene difference. Further analyses for additional local populations belonging to R. amurensis will be necessary to clarify the taxonomic status.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.1
• /
• pp.57.1-57.1
• /
• 2013

Non-LTE 항성대기모형인 Tlusty 모형의 합성색지수와 성간소광을 매우 적게 받은 산개성단에 있는 별들의 색지수를 바탕으로 O와 B형 별의 고유색지수 관계를 채택하였다. 태양인근 3kpc 내에 있는 약 190개 젊은 산개성단의 가시광 및 근적외선 2MASS JHKs 관측자료와 위에서 채택한 고유 색지수 관계를 적용하여 색 초과비 E(V-I)/E(B-V), E(V-J)/E(B-V), E(V-H)/E(B-V), 및 E(V-Ks)/E(B-V)를 얻고, 색 초과비와 $R_V$의 관계를 사용하여, 각 성단의 성간소광법칙 $R_V$를 결정하였다. 국부 나선팔의 백조자리 방향과 Per 나선팔에 있는 산개성단들은 약간 작은 $R_V$를 보이며, 큰개자리 방향의 국부 나선팔에 있는 산개성단은 정상적인$R_V$를, 그리고 Sgr-Car 나선팔에 있는 산개성단들은 약간 큰 값을 보였다. 이 결과는 최대 편광도를 보이는 파장과 $R_V$의 관계로 얻을 수 있는 양상과 잘 일치한다.

• Journal of Korean Society of Forest Science
• /
• v.101 no.2
• /
• pp.236-243
• /
• 2012

The leaf growth and physiological characteristics of Forsythia saxatilis were investigated at six natural habitats under different light intensities in Bukhansan in order to figure out an appropriate growth environment for conservation and restoration of F. saxatilis that is Korean endemic plant designated as rare and endangered species. Relative light intensities (RLI) at six habitats showed from 10% to 78% of the full sun. Leaf length, leaf width, leaf area and dry leaf weight of population under highest relative light intensity (78%) were the highest. The ratio of dry leaf weight to leaf area increased with the increase of RLI. The content of photosynthetic pigments such as chlorophyll a, b and carotenoid were the highest at 78% of RLI, whereas the ratio of total chlorophyll to carotenoid content reduced according to the increase of RLI. Photosynthetic parameters, such as photosynthetic rate, also increased with the increase of RLI. The total nonstructural carbohydrate (TNC) was 1.5 times higher at 78% of RLI than that at 10% of RLI and the total soluble sugar (TSS) was the highest at 78% of RLI. In conclusion, leaf characteristics and physiological characteristics have high positive correlation with light intensity. Therefore, light condition should be primarily considered to improve growth and physiology characteristics of F. saxatilis under low light intensity.

• The Bulletin of The Korean Astronomical Society
• /
• v.27 no.1
• /
• pp.51-51
• /
• 2002

• The Bulletin of The Korean Astronomical Society
• /
• v.35 no.2
• /
• pp.79.1-79.1
• /
• 2010

세종 산개성단 탐사관측 연구의 일환으로 중년 산개성단 NGC 2353에 대한 UBVI CCD 측광을 수행하였다. 측광학적인 방법으로 성단 내의 구성원을 선정하였으며, 이로부터 이 성단의 성간소광과 거리를 각각 E(B-V)=$0.10\pm0.02mag$와 $d=1.17\pm0.04\;kpc$으로 얻었다. 성단 구성원의 공간적인 분포를 통해서 성단의 형태가 북서 방향에서 남동 방향을 잇는 축을 중심으로 타원의 형태를 띠고 있는 것을 발견하였다. Padova 그룹이 제시한 이론적인 등연령 곡선을 관측한 색등급도에 맞춤으로써 이 성단의 나이를 1억 3천만년으로 추정하였으며, 이는 기존 연구보다 나이가 많은 것으로 나타났다. 구성원의 거리지수 분포에서 이 성단의 거리지수보다 밝은 곳에 나타나는 쌍성의 분포를 Gaussian 분포와 맞추어 $46\pm4%$ 정도의 최소 쌍성비율을 추정하였다. 마지막으로 광도함수와 질량함수를 유도하였고, 질량함수의 기울기는 $\Gamma=-1.4\pm0.2$를 얻었다.

• The Bulletin of The Korean Astronomical Society
• /
• v.25 no.1
• /
• pp.41-41
• /
• 2000

• Journal of Korean Society of Forest Science
• /
• v.100 no.4
• /
• pp.609-615
• /
• 2011

Forsythia saxatilis is a Korean endemic plant designated as rare and endangered by the Korea Forest Service (KFS). Growth and physiological characteristics of F. saxatilis were investigated under two different light intensities in order to figure out an appropriate growth environment for conservation and restoration of the species in its natural habitat. Shoot length, leaf size and weight, photosynthetic pigment content and photosynthetic parameters were measured for F. saxatilis grown at two experimental plots under relative light intensities (RLI) of 20% and 60% of the full sun, respectively. Fresh leaf weight of plants grown under high relative light intensities (RLI-60) exceeded that of plants grown at 20% RLI. The ratio of fresh leaf weight to leaf size at RLI-60 was 1.47 times superior comparing to that recorded at RLI-20. The content of photosynthetic pigments such as chlorophyll a, b and carotenoid were higher in plants grown at RLI-60, whereas the ratio of total chlorophyll to carotenoid content was higher in the leaves at RLI-20. Photosynthetic rate, stomatal conductance and transpiration rate at RLI-60 were, respectively, 2.5, 2.65 and 1.79 times higher comparing to those recorded at RLI-20. Water use efficiency, however, was higher at RLI-20. The chlorophyll/nitrogen ratio was 1.83 times higher at RLI-20 than at RLI-60. In contrast, the ratio of net photosynthesis to chlorophyll content at RLI-60 was 2.58 times higher than that of RLI-20. In conclusion, light intensity might be the major factor affecting growth and physiological characteristics of F. saxatilis grown under canopy of tall tree species.

• Journal of Korean Society of Forest Science
• /
• v.102 no.1
• /
• pp.136-142
• /
• 2013

Optimal condition for pollen germination was suggested as a basic research of flowering physiology in order to identify the characteristics of flowering and seed setting of rare and endangered Forsythia saxatilis Nakai. Pollen samples were collected during flowering time from the end of March to the beginning of April. First, a suitable germination temperature, medium sucrose concentration and germination time were determined for pollen germination and pollen tube elongation in vitro, and then an optimal pH of culture medium. Pollen germination and tube elongation were significantly different among the levels of germination temperature, sucrose concentration and germination time. Interactive effects were observed between germination temperature and time, germination temperature and sucrose concentration, germination time and sucrose concentration. Pollen germination was the highest at $10^{\circ}C$ and increased with the increase of sucrose concentration, whereas it had no relation with germination time. In addition, pollen germination and tube elongation did not increase at more than 15% of sucrose concentration and 24 hours later. Pollen germination was the highest at pH 5 (20.8%) and the lowest at pH 6 (3.8%). In conclusion, $10^{\circ}C$, 15% sucrose and pH 5 were proposed as the optimal condition for pollen germination 24 hours later of pollen culture.

• Journal of Korean Society of Forest Science
• /
• v.102 no.3
• /
• pp.372-381
• /
• 2013

The leaf growth and physiological characteristics of Forsythia saxatilis were investigated under different relative light intensities (RLI) and fertilization levels in order to find out the optimum environmental conditions for in-situ restoration. RLI and fertilization were four levels (30%, 43%, 63% of full sun and full sun) and three levels (non-fertilization, 2 times and 3 times of average forest soil in Korea), respectively. According to the increase of fertilization level under all RLI, leaf area increased and leaf dry weight and the ratio of leaf dry weight to leaf area decreased. As the fertilization level increased, photosynthetic pigment contents such as chlorophyll a, b and carotenoid under all RLI decreased. And pigment contents were the highest under full sun in the same fertilization level. Foliar nitrogen content under fertilization was higher than that under non-fertilization, and chlorophyll/nitrogen ratio decreased with the increase of fertilization level under all RLI. The increase of photosynthetic rate was observed with the increase of fertilization level at 63% of RLI and full sun, and dark respiration rate under fertilization was lower than under non-fertilization. Apparent quantum yield was lower at non-fertilization than that of fertilization, and it was highest at 63% of RLI under the same fertilization level. In conclusion, leaf growth and physiological characteristics of F. saxatilis could be improved under higher light conditions and fertilization.