• Korean journal of applied entomology
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• v.32 no.3
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• pp.354-371
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• 1993

Behavior of adult females of the smoky brown cockroach was observed for 10-15 days continuously by using computer and the automatic sensoring system. Under the light condition of l2L~ 12D, individual variations were generally higher and the periodicity appeared less in terms of the presence time at the micro-habitats and the locomotory activity. The smoky brown cockroach appeared 20.42, 11.50, 6.31 and 2.66 % in a day in averages respectively at the shelter and the places for other individuals, feeding and drinking. It stayed 20.29 % in a day at the shelter when food, water, and other individuals were not supplied. Visiting rates were higher at the feeding and dnnking places than at. the ot.her micro-habitats. The degree of t.he locomotory activity was relatively lower when food, water, and other individuals were not supplied t.han when they were supplied. The Pnncipal Component Analysis (PCA) on the presence at the micro-habitats showed that. t.he presence pattern for each mdividual appeared differently (Q mode) while the differem time zones were grouped to the photophase and scotophase (R mode). When food, water, and other individuals were supplied the degree of grouping was higher at the shelter than at the places for feeding and drinking. When the act.ivityand the presence time at the different micro-habitats were jointly analyzed by PCA, the achvity of the female smoky brown cockroach appeared in relation with the presence time ( %) at the places for feeding and other individuals.

• Korean journal of applied entomology
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• v.28 no.4
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• pp.229-236
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• 1989

A combined field release of indigenous larvivoroug fish (Aplocheilus latipes) and hybrid herbivore (Tilapia mossambicus miloticus) was conducted to determine the effectiveness of biological control, in particular, against malaria vector (anopheles sinensis), breeding in weedy habitat of rice fields at the University rice paddies at Suwon during the period of June through September in 1988. A combined fish introduction at the release rate of 2.0 fish per $M^{2}$ for Aplocheilus and 1-pair $10M^{2}$ water surface for Tilapia resuited in 70.8% Anopheles larval reducton in a week period, the rates of rontrol increased to 73. 5% and 80.2% in 4th and 5th week respectively after the fish introdurtion, maintaining mosquito suppression in range of 80~82% control after the 5th week against Anopheles and Culex spp. combined. In a single fish treatment with Aplocheilus at 2.0 $fish/M^{2}$ release rate, Anopheles larval reduction ranged on the average 51.4~56.5%in 4 wrek period which was later integratpd with B.t.i. (Rl53.78) treatment at 1.0 kg/ha dosage rate to suppress vector mosquito population down and the the results was compared with that of combined fish introdurtion.

• Korean journal of applied entomology
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• v.48 no.4
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• pp.439-445
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• 2009

Species richness (number of species) of the butterfly community in the Gwangneung forest, Korea, was estimated using data of the long-term butterfly monitoring, which had been carried out 291 times in the Korea National Arboretum or forest area of Gwangneung from 1998 to 2008. Abundance of each butterfly species was monitored using the line-transact method. In the present study, 13,333 butterflies belonging to 112 species were observed. Species accumulation curve and species richness was obtained using a software, EstimateS. The species accumulation curve shows an increase tendency even at 291 survey times, implying the possibility of the presence of a few unfound species. However, values of species richness estimated by the seven estimators were stabilized around 240-250 survey times. Species richness estimated by the estimators ranged from 120 species to 141 species with 128 species in average. However, the figure estimated by the previous studies since 1958 was 148 species. We estimated the reasonable scale of species richness on the base of recent analysis on the change of butterfly species. Species richness of the Korea National Arboretum was higher than that of natural forest and of plantation. However, species richness of butterfly was not different between natural forest and plantation. It is likely that increase of grasslands and habitat diversity in arboretum led to the increase of species richness of butterfly community.

• Korean Journal of Plant Taxonomy
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• v.39 no.1
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• pp.29-34
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• 2009

The Chrysanthemum zawadskii complex is demarcated from other species by having the white and pink ligulate flowers. Its morphological characters are greatly diversified, so that various classification systems have been suggested. The character of leaf thickness has been mentioned as the characteristic for recognizing some of infra-specific taxa within this complex. In this study, we used longitudinal leaf sections to investigate the leaf thickness and cell number of leaf blades of 13 populations including those of the members of the C. zawadskii complex, as well as 4 populations of the related species of C. boreale and C. indicum. From the result, it was clear that the leaves were thicker in populations of C. boreale, C. indicum and C. zawadskii complex (diminishing in that order), and that the leaves were composed of about 9 cell layers in all populations. Within the C. zawadskii complex, leaf shape and thickness varied among the populations. It was very interesting that the taxa with restricted distribution, like C. zawadskii var. tenuisectum, C. zawadskii var. alpinum, C. zawadskii var. lucidum, and C. zawadskii subsp. coreanum had a thicker leaves than found among widely occurring taxa. From this, leaf thickness is supposed to be an adaptation to the unique habitat of each population.

• Korean Journal of Plant Taxonomy
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• v.43 no.4
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• pp.267-273
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• 2013

This study employed inter-simple-sequence repeat (ISSR) to assess genetic variation among 189 individuals representing 10 populations (nine in Korea and one in Japan) of Millettia japonica, which has recently been lifted from the endangered species of Korea. The calculated Shannon's information index value (I = 0.2689) of the species was appreciable and was higher than other endangered leguminous woody taxa. Gochang (I = 0.2968), Namhae (I = 0.2951), and Mt. Toham (I = 0.2823) populations showed relatively high genetic diversity, whereas the Kyushu (in Japan) population (I = 0.2487) exhibited the lowest. The results of an analysis of molecular variance indicated that 86.49% of the diversity was attributed to within populations, and 13.51% to differences among populations, suggesting that M. japonica populations do not have significant geographic differentiation and that the gene flow between populations exists to some extent (Nm = 1.8446). Continuous habitat monitoring should be conducted to conserve genetic diversity of M. japonica, particularly for those populations with relatively high genetic diversity. Selection of many individuals from the populations in Gochang, Namhae, and Mt. Toham is thought to be an appropriate strategy for ex situ conservation of M. japonica in Korea.

• Korean Journal of Plant Taxonomy
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• v.43 no.2
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• pp.81-89
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• 2013

In general, studies of aerial parasitic plants known collectively as mistletoe have been carried out to investigate their ecological and agricultural characteristics. However, with the recently increased level of interest in medicinal resources, research on different types of Korean mistletoe has also increased. This study was carried out to review the work on the taxonomy and ecology of Korean mistletoe in preparation for the industrial use of these plants in the future. Mistletoe types are flowering plants belonging to Santalales, which exist in the form of parasites on the branches of trees or shrubs. In Korea, five taxa of four genera in two families of mistletoe exist: Viscum coloratum (Komarov) Nakai f. coloratum, Viscum coloratum (Komarov) Nakai f. rubroaurantiacum (Makino) Kitagawa and Korthalsella japonica (Thunb.) Engl. in Santalaceae, along with Loranthus tanakae Franch. et Sav. and Taxillus yadoriki (Sieb. ex Maxim.) Danser in Loranthaceae. As taxonomic studies of these species remain insufficient and given that the distribution ranges of these species are very wide, further observations pertaining to the morphological variations in each species are necessary. The distribution of mistletoes is known to be determined by the host specificity, the interval between the hosts, the environmental condition, the habits of the host plant, the eating characteristics of mediators in the area, and their habitat selection features.

• Journal of Plant Biology
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• v.35 no.4
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• pp.317-322
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• 1992

The nitrogen fixation activity and environmental factors of Lespedeza bicli!oy Turcz, forming annual root nodules by symbiotic Rhizobium sp. were analyzed in the field conditions during the growing period. Seasunal changes of $N_2-fixation$ activity showed the maximum value of $120\;\mu\textrm{M}\;C_2_H4{\cdot}noduie\;g\;fw^{-1}{\cdot}hr^{-1}$ during the active growing period (June) and varied significantly depending on the growth phase and environmental factors. The maximum activities were attained at the conditions of pH 7, $30^{\circ}C$ of temperature, 18 Kpa of oxygen partial pressure and inhibited by water stress and nitrogen sources. The habitat soil was weak acidic and poor in nitrogen, phosphorus and organic matter contents. The leaf area ratios and chlorophyll contents were ranged from 442 to $48;\textrm{cm}^2{\cdot}g\;dw^{-1}$ and from 33 to $38\;\mu\textrm{g}\;chI{\cdot}\textrm{cm}^2$. Nitrogen contents in each organ showed the maximum of 46, 19 and $11\;mg{\cdot}g\;dw^{-1}, respectively for leaf, rool and stem in the early period. The highest phosphorus contents were 4.2, 1.2 and $0.6\;mg{\cdot}g\;dw^{-1}$, respectively for leaf. root and stem in early growing period. The allocation ratios of nitrogen quantity showed 60% for leaves and 73% for roots during the active and late growth period, and 22% [or stems in average. The allocalion ralios o[ phosphorus quantity showed 58% for leaves during the most productive period, 70% for roots in the pre-growth stage and 26% for stems in average.verage.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.233-233
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• 2017

Algal communities are important to maintain the aquatic ecosystems function. Algae have short life cycles, they respond quickly to environmental change and their diversity and density can indicate and the quality of their habitat. The bloom forms before the rice seedings have emerged, it may present a physical barrier that prevents the seedlings from penetrating the floodwater. Wind may also move the algal bloom, pushing the young plants beneath the surface. Another harmful action develops when the water dries up and the algae form a layer at the bottom of the field. The layer envelops the seedlings, which are not yet deeply rooted, and drag them to the surface when the water is let in again. Soil utilization pattern can be the mail facter affecting soil physico-chemical properties, especially in soil phosphorus (P). Solid content of the algae culture solution increased with the increase in the nitrogen rather the phosphors concentration. Phosphoric acid was treated with conventional treatments (100-0%, before transplanting time-tillering stage), 50-50%, 0-100%, and un-treated. The herbicide was treated on the 7 DAT (day after transplanting). Green algae samples were collected 20 DAT. Total phosphoric acid was the highest at 0.06 in 50-50% treatment in 20 DAT. The amount of green algae was about twice (9.8 mg/20ml) that of un-treated. Total number of green algae was 54 species(Green algae 35 species, Euglena 9 species, Stone wheel 10 species). Among the phosphoric acid treatment methods, the number of occurrences of green algae were the highest with 39 species in 0-100%, followed by 50-50%, 28 species, conventional treatments, 22 species, non-treatment, 18 species, respectively. Rice Yield was not significantly different by phosphoric treatment time, but slightly higher than un-treated. The maximal algal biomass was observed about 2weeks or 1 month after transplanting; the subsequent decrease of the biomass was related to the consumption by grazers and to a deficient light under the rice canopy. Maximal algal growth was observed just before tillering. To estimate the suitable method of phosphorus application in puddled-soil drill seeding of rice, available phosphorus appearance of algal water bloom, and rice yield were investigated in paddy soil of rice-barley double cropping system.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.267-276
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• 2001

The downstream reach of the Han River adjoining Seoul in Korea was the upper boundary of an estuary where tidal effect on the flow rate could be exerted. According to the comprehensive river regulation project, the river was channelize dand impounded by two overflow dams, which provided favorable condition for algal growth in this sewage polluted eutrophic reach. In this study primary productivity of phytoplankton was measured in the down reach and the autochthonous and allochthonous organic carbon loadings were estimated. Primary production of phytoplankton measured by C-14 uptake and P-I model method ranged from 140 to $4,890\;mgC\;m^{-2}\;d^{-1}$ (median value $1,865\;mgC\;m^{-2}\;d^{-1}$) showing the level of eutrophic lakes. Phytoplankton density that varied according to water flow rate was highest in spring. Allochthonous organic carbon loading was dominated by sewage input through tributaries in most of days except flood flow period. The average proportion of autochthonous carbon generation by phytoplankton was 40.9%, which is very high proportion for a lotic habitat.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.165-172
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• 2020

Heavy metals are common pollutants in the freshwater environment and have toxicological effect in habitat organisms. The heavy metals highly accumulated in sediment and organism, and observed various physiological responses. In this study, we investigated the molecular response to heavy metal toxicity (Al, Aluminum; Cr, Chromium; Cu, copper; Mn, Manganese; Zn, Zinc) through expression of heat shock protein 40, 70, 90 (HSP40, 70, 90), cytochrome 450 (CYP450), Glutathione S-transferase (GST) and Serine-type endopeptidase (SP). HSPs showed up-regulation in Cu and Zn exposures. Furthermore, HSPs expression in treated groups tended to be higher than the control group. The tendency of CYP450 and GST mRNA expression was higher for Cr and Cu than for other exposure group. The expression of SP gene was low at Al exposure and other group were measured to be similar to control. These results suggest that heavy metal toxicity in freshwater ecosystem may affect physiological and molecular process. Also, the comprehensive gene expression in the aquatic midge Chironomus riparius give useful information to potential molecular biomarkers for assessing heavy metal toxicity.