• Korean journal of applied entomology
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• v.38 no.2
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• pp.93-99
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• 1999

We investigated the effect of constant photoperiod (16L : 8D, 12L : 12D, 8L : 16D), on the oviposition, parasitism, and emergence of Trichogramma dendrolimi. Also during 16L : 8D condition circadian, oviposition and emergence of this species on artificial eggs were checked every 2hrs. When twelve eggs of Antheraea pern~i and artificial eggs were provided, the wasps had the highest rate of oviposition in the first day, and decreased dramatically there after. In these different photoperiod, the total oviposition numbers per A. pernyi eggs by the wasp were 161.8 in 16L : 8D, 145.8 in 121 : 12D and 128.5 in 8L : 16D respectively in the first day. On the other hand for the artificial egg in 16L : 8D photoperiod, the total oviposition number per egg was 106.8 in the first day, 26.6 in the 2nd day and 21.3 in the 3rd day. The rate of emergence from A. pernyi eggs was not different depend on wasp's day age, however in the artificial eggs, after the first day's 84.7% decreased considerably. The emergence rate from artificial eggs was the highest comparatively between 04:OO-0600 hours.

• FLOWER RESEARCH JOURNAL
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• v.16 no.1
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• pp.63-70
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• 2008

This experiment was conducted to acquire the basic data necessary for the artificial pond greening. Eighty four hydrophytes collected from 11 domestic small ponds and a farm were used in this experiment. The size of the artificial pond used was $6m{\times}3m{\times}1.5m(length{\times}width{\times}depth)$. Twelve months after planting, species were selected for their high ornamental values and tissue contents of N and P in each month. Tissue contents of N in Trapha nantan, Nymphoides indica, Nymphaea hybrid, and Murdannia keisak were high. Tissue contents of P in Monochoria vaginalis and Murdannia keisak were also high. The pH of artificial pond stabilized at a 6.8~7.6 range from May 2005 to March 2007. The EC was low in summer and high in autumn. From April to October, 5, 19, 23, 32, 31, 28, and 26 species, respectively, were selected for artificial pond greening. One year after planting, vegetation changed from 78 species (Potamogeton octqandrus, Salvinia natans, Potamogeton malaianus, etc.) to 38 species (Scirpus tarbernaemontani, Scirpus karuizawensis, Scirpus triqueter, etc.). Species diversity in the artificial pond was as follows, indicating it being a stabilized artificial pond; 38 species, 1,437 total number of plants, species richness index of 11.72, and maximum diversity index of 0.97.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.150-164
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• 2022

This study was conducted to provide basic information for the development of silvicultural guidelines and manuals. This was achieved through analysis of tree and stand characteristics according to the first and second thinning in Korean white pine plantations. Data were collected from permanent plots installed at Korean white pine plantations according to thinning intensity, and residual tree and stand variables, including diameter at breast height (DBH), volume, and mortality at age 19-43, were analyzed using data repeatedly collected in 4-5 measurements by experiments. According to one-way variance of analysis, tree DBH and volume were significantly different according to thinning intensity (p<0.05). DBH distribution was skewed to the left side over time as thinning intensity was heavier. Thus, tree DBH values were larger in heavy thinning plots with increased age. The periodic annual increment (PAI) of DBH was higher with heavier thinning intensity and fewer years after thinning. The PAI range by thinning intensity was 0.48-0.95 cm/year at age 19-24. In addition, the PAI increased in heavy thinning plots after the second thinning; The PAI range by thinning intensity was 0.29-0.67 cm/year after the second thinning at age 37-42. The PAI of tree volume differed according to thinning intensity, and the PAI value did not decrease obviously, in contrast to the pattern of the DBH PAI. Stand volume was generally higher in high-density stands, and the PAI of stand volume was high in unthinned and light thinning plots. Mortality was highest in unthinned plots, and the differences in mortality according to thinning intensity increased over time. Consequently, the growth of DBH and tree volume was lower as stand density increased, but this growth was facilitated with appropriate first and second thinning operations.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.559-565
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• 2014

The fish and attached fish eggs by artificial floating island in lake Soyang was investigation from May to June 2013. The observed fish at the floating island during the survey period were Zacco platypus (5.2 %), Siniperca scherzeri (1.0 %), Lepomis macrochirus (90.8 %) and Micropterus salmoides (3.0 %) at the Cheongpyeong-ri, Cyprinus carpio (0.4 %), Z. platypus (54.6 %), L. macrochirus (20.3 %) and M. salmoides (24.7 %) at the Ungjin-ri. The collected species at the neighboring facility were 22 species belonging the seven families. Among them, exotic species such as Carassius cuvieri, L. macrochirus and M. salmoides. Also, Z. platypus (30.4 %), L. macrochirus (18.9 %), Opsariichthys uncirostris amurensis (15.4 %) and Hemibarbus labeo (9.3 %) were numberous. Attached fish eggs number were 708,800 (800 per $m^2$) at the Cheongpyeong-ri and 974,500 (1,100 per $m^2$) at the Ungjin-ri. The fish eggs number were 504,920 of the Carassius auratus (212,640 at the Cheongpyeong-ri, 292,280 at the Ungjin-ri) and 1,178,380 of the C. carpio (496,160 at the Cheongpyeong-ri, 682,220 at the Ungjin-ri). The hatched eggs number were 350,505 of the C. auratus(102,067 at the Cheongpyeong-ri, 248,438 at the Ungjin-ri) and 811,222 of the C. carpio (238,157 at the Cheongpyeong-ri, 573,065 at the Ungjin-ri).

• Journal of Sericultural and Entomological Science
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• v.50 no.1
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• pp.27-32
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• 2012

The aim of this study is to develop indoor-rearing methods of the diving beetles. In nature, both the adult diving beetle and its larvae are voracious aquatic predators. The larvae beetles hunt relatively bigger size of tadpoles and small fish for food source. However, due to difficulties of the food supplement for rearing diving beetles at indoor-condition further motivated us to develop new artificial food. Three separate experiments were performed. In the first experiment, adult beetles were provided with one of the several food choice treatments to self-compose their preferred foods that are affordable on the market at lower price. The second experiment was also to develop artificial diet that is possible for rearing larvae beetle under indoor condition. The larvae beetles were restricted to raw squid, artificial food source and mosquito larvae as a control at the first stadium and small fish and raw squid during second to third stadium duration. According to our result, adult beetles selected a food that made of boiled squid and dead small fish while, the young larvae consumed small fish, mosquito larvae and raw squid. Although, the larval food restriction on law squid caused noticeable decrease in survival, the result still supported the possible survival rate of keeping larvae at indoor condition. Moreover, pupation rate experiments, in which groups of larvae were placed at different mats, natural soil and fermented sawdust, showed that 80% of diving beetles pupated on the sawdust. This result indicates that female beetle preferentially selected to oviposit along soft and moist area.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.116-125
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• 2017

Alpine plants with a scarcity of pollinators in harsh environments have been believed to undergo selfing for reproductive assurance; however, contradictory evidence is also available. Snowmelt regimes in alpine areas function to change life history characteristics of alpine plants such as flowering time and duration; yet the effects of snowmelt regimes have never been tested in alpine plants in Korea. This study was conducted to investigate the dichogamy, mating systems, and flowering characteristics of Megaleranthis saniculifolia populations [early and late snowmelt plots (ESP and LSP, respectively)] in a subalpine area of Sobaeksan Mountain in Korea. M. saniculifolia exhibited incomplete protogyny in that despite early maturation of pistils, maturation times of pistils and stamens within flowers were partly overlapped. Control and hand-outcrossing treatments produced significantly higher number of follicles and seeds per flower than autonomous and hand-selfing treatments. Based on the aggregate fruit set, the auto-fertility index (AI) and self-compatibility index (SI) were 0.33 and 0.50, respectively. Snowmelt occurred 10 days earlier in ESP than in LSP, thereby ESP and LSP showed distinct differences with regard to flower longevity and season, but showing no difference in peak flowering dates. We concluded that M. saniculifolia is an incomplete protogynous and largely outcrossing plant requiring pollinator service. Temporal variation in snowmelt time and subsequent changes in flowering characteristics under climate change may further threaten the population persistence of M. saniculifolia which has already been designated as endangered species in Korea.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.441-453
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• 2015

In this paper, according to the illuminance at night with artificial lighting in downtown Seoul, trees flowering and leaf growth rate was performed as a case study to examine whether there is a difference. The illuminance was measured at 78 points on a total of 26 points, the range of illuminance were divided into three groups considering land use, Group A (plots 1-7) were 4.90 ~ 112.50 lx, Group B (plots 8 to 18) were 0.45 ~ 42.40 lx, group C (plots 19 to 26) were 0.28 ~ 22.10 lx. According to the One-way ANOVA on illuminance difference, the survey groups were classified into three groups. To survey the ratio of the flowering Prunus yedoensis and Rhododendron spp. and to survey the ratio of leaf growth Zelkova serrata, Ginkgo biloba, and Acer palmatum each 30 individuals were investigated. Rhododendron spp. to study the ratio of the flowering and Acer palmatum to study the ratio of leaf growth were determined to be useful as indicator woody species according to the correlation. The higher illuminance of night lighting is, the faster flowering and leaf growth of trees will be by correlation between the mean illuminance of each group and the flowering and leaf growth of trees. In the future, should be made a more detailed study of how much affect to the trees with some impact on the level of light pollution at night lighting.

• Journal of Korean Society of Forest Science
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• v.87 no.4
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• pp.543-548
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• 1998

Portions of chloroplast genes(psbD and rbcL) were amplified from Pinus thunbergii(Japanese black pine : black pine) and Pinus densiflora(Japanese red pine : red pine) by PCR and digested by a restriction enzyme, HaeIII, respectively. Two species specific cpDNA markers were identified. With the observed cpDNA markers, paternal inheritance of cpDNA in pine hybrids was verified in an artificial hybrid family between black pine(Chollanam 37) and red pine(Chungchongbuk 3). On the basis of paternal inheritance of chloroplast genome in a hybrid, 2 portions of cpDNA amplified from 115 individuals of Pinus densiflora for. erecta were screened to detect any traces of black pine specific cpDNA markers in P. densiflora for. erecta which has been postulated as an introgressive hybrid between red pine and black pine(Hyun el al., 1967). All the analyzed individuals of Pinus densiflora for. erects revealed the identical profiles of HaeIII digested psbD and rbcL genes to red pine. This result suggests that there is no introduced chloroplast genome of black pine in Pinus densiflora for. erecta and that there is no concrete evidence of treating P. densiflora for, erecta as an introgressive hybrid between red pine(♀) and black pine(♂).

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.422-430
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• 2000

Three-year-old Pinus koraiensis seedlings, transplanted in brown forest soils originating from granite were treated with simulated acid rain of pH concentrations 5.6(control), 4.0, 3.0, 2.5 and 2.0 for 210 days from April 21 to November 17, 1999. Visible injury of the seedlings were observed at the pH 2.0 and pH 2.5 treatments. The total dry weight of the seedlings decreased at pH 2.0 treatment compared with that of the control, and T/R ratio increased at pH 2.0 treatment compared with others. The elements in each part of the seedlings, concentrations of Ca, P and content of chlorophyll in needles increased at the pH 2.0 treatment compared with the control. The concentration of N in the needles of the seedlings increased as the soil pH decreased. As the treated pH was lowered, soil pH has decreased, and concentrations of Ca, Mg, Al, and Mn increased, especially at pH 4.4. In addition, there was a strong correlation(r=0.90, p<0.05 ; r=-0.94, p<0.01) between the dry weight of the seedlings and the pH and Al concentration of the soils. Therefore, the pH and Al concentration in the soil may be useful indicator for assessing the effect of acid rain on the growth of woody plants.

• The Korean Journal of Malacology
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• v.27 no.2
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• pp.99-105
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• 2011

This study was conducted to compare the species composition of sessile organisms on the artificial substrates of PVC submerged at different time intervals and duration in Jangmok Bay, Geoje Island, southern coast of Korea. Three PVC plates were submerged at one month interval from March to October and retrieved in November, 2007. A mussel, Mytilus galloprovincialis exclusively occupied the artificial substrates submerged from March to April and occurred as a dominant species to July. An ascidian, Styela plicata occurred as a dominant sessile species from May to August. Balanus amphtrite, Bugula sp., and hydrozoans occurred as dominant species on the plates submerged from July to September. There was a mis-match between the peak time of settlement and dominance of sessile organisms due to the interspecies competitions when the PVC plates were retrieved in November. There was no clear relationship between submerged duration and the abundance of sessile organisms due to the different settlement period. M. galloprovincialis seemed to be a strong competitor which could exclude the previous recruiters of macroalgae by overgrowth and occupy the substrate surface and maintain its high population density by preventing the settlement of other species until late autumn. These results suggested that the composition of sessile organisms in vacant hard substrates could be determined by the combined effects of supply-timing of larvae and post-settlement competitions.