• The Korean Journal of Pesticide Science
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• v.12 no.3
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• pp.222-228
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• 2008

Algal Growth-inhibition tests were conducted with 6 pesticides butachlor GR (5%), butachlor EW (33%), isoprothiolane GR (12%), isoprothiolane EC (40%), diazinon GR (3%) and diazinon EC (34%) to determine their comparative toxicity to three species of freshwater green algae Selenastrum capricornutum, Scenedesmus subspicatus, Chlorella vulgris and one species diatom Nitzschia palea. The test species were exposed to the test pesticide for 72 hours and the toxicity represented $EC_{50}$ value calculated by the reduction in growth rate at 72 hours. The toxicity of EC or EW formulation to green algae and diatom was higher than the toxicity of GR formulation at all test in this study. Also, the toxicity of EC formulation was higher than the toxicity technical pesticide. These results indicate that the types of pesticide formulation may affect on their toxicity on algae and the green alga, S. capricornutum and S. subspicatus were more sensitive than C. vulgris. Also, the sensitivity of the diatom, N. palea showed equal or lower than S. capricornutum, S. subspicatus but more sensitive than C. vulgris.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.407-414
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• 2007

In order to evaluate the physicochemical properties of sludge compost and to identify the effects water-extracts from sludge compost in 2, 6, 8, 12 weeks of decomposing process on seed germination and root elongation in cabbage, lettuce, soybean and barley plants was investigated. The content of total nitrogen in sludge compost increased slightly in 6 weeks decomposing process, and then decreased gradually. Organic matter content decreased continuously overall decomposing process. As decomposition was processing, pH of sludge compost decreased slightly, and EC increase within 6 weeks decomposing process, and then decreased. The content of nitrogen in water-extracts from sludge compost increased within 8 weeks decomposing process and decreased in 12 weeks decomposing process. The content of ammonium nitrogen was similar with that of total nitrogen, and the ratio of ammonium and nitrate increased within 8 weeks, and then decreased. Cation content and EC decreased the late of decomposing process and pH didn't change. The water-extracts from sludge compost during decomposing process inhibited seed germination and root elongation in cabbage (Brassica campestris), lettuce (Lactuca sativa), barley (Hordeum vulgare) and soybean (Glycine max). The inhibition of root elongation in cabbage was greater than that of relative seed germination, whereas relative seed germination in lettuce was more inhibit than root elongation. Relative seed germination and root elongation in soybean were inhibited slightly, but those of in barley was inhibited strongly. In this study, we would identify the effects of water-extracts from sludge compost on seed germination and root elongation was different to the species of seed. The inhibition of seed germination and root elongation treated with the water-extracts which extracted from sludge compost in the early stage of decomposing process was greater than that of in the late stage of decomposing process.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.510-515
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• 2014

Duckweed (Lemna perpusilla J. Torrey) is a typical floating aquatic macrophyte that has been used for evaluating phytotoxicity of toxicants. In this study, we evaluated the responses of duckweed to PAHs and ammonium as toxicants that frequently affect the growth of plants in polluted industrial and agricultural areas. As the duckweed is growing in aquatic environment, the PAHs and ammonium were incorporated into nutrient solution and the fronds were cultured hydroponically. Frond growth was responded differentially to the concentration and type of PAHs. The severe inhibition of frond growth was observed in the treatment of fluorene. Fluoranthene and pyrene, however, showed weak inhibition of frond growth. The latter PAHs that showed weak inhibition did not reduced frond number at the low concentration of 30 ppm. Pigment contents were also responded differentially. Phenanthrene and fluorene reduced chlorophyll content more strongly than fluoranthene and pyrene. Carotenoids, well-known antioxidative compound, was relatively increased at the low concentration of PAHs up to 30 ppm by the treatment of fluoranthene and pyrene, suggesting an increased antioxidative activity in fronds. Ammonium treatment showed higher inhibitory effect even low concentration of 3 mM.

• The Korean Journal of Pesticide Science
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• v.12 no.1
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• pp.82-87
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• 2008

Algae are vital in the primary production of the aquatic ecosystem, having been considered as good indicators of the bioactivity of pesticides. Algae have short life cycle, respond quickly to environmental change and their diversity and density can indicate the quality of their habitat. The purpose of the study was to determine the growth inhibition effects of butachlor (Tech. 93.4%) and $K_2Cr_2O_7$ (Tech. 99.5%) in Selenastrum capriconutum, Scenedesmus subspicatus, Chlorella vulgaris and Nitzschia palea during and exposure period of 72 hours. The toxicological responses of S. capriconutum, S. subspicatus, C. vulgaris and N. Palea to butachlor, expressed in individual $ErC_{50}$ values were 0.0022, 0.019, 8.67 and $4.94\;mg\;L^{-1}$, respectively. NOEC values were 0.0008, 0.0016, 5.34 and $2.92\;mg\;L^{-1}$, respectively. S. capriconutum was more sensitive than the other algae species. The toxicological responses of S. capriconutum, S. subspicatus, C. vulgaris and N. palea to $K_2Cr_2O_7$ expressed as $ErC_{50}$ values were 0.91, 0.78, 0.85 and $0.57\;mg\;L^{-1}$, respectively. NOEC values were 0.2, 0.2, 0.2 and $0.18\;mg\;L^{-1}$, respectively. Growth inhibition of S. capriconutum, S. subspicatus, C. vulgaris and N. palea from PEC of butachlor were 100, 75, 0 and 0%, respectively.

• Journal of the Korean Wood Science and Technology
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• v.42 no.1
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• pp.41-48
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• 2014

To development of the low toxic preservatives, we prepared 29 kinds of chemicals using dinotefuran of low toxic insecticide, IPBC and propiconazol of fungicide, and clove oil has fungicidal activity, but is harmless to humans. It was conducted to investigate the inhibitory effectiveness of mycelial growth and anti-mold effectiveness to treated PDA medium and wood specimen with prepared chemicals. It was not showed anti-mold effectiveness that solvent and emulsifier form preservatives. Therefor, we thought that only four component, dinotefuran, IPBC, propiconazol and clove oil, has anti-mold effectiveness. In the PDA medium test, the preservative which has much IPBC showed high anti-mold effectiveness. By the wood specimen test, it was known that many prepared preservatives which showed good inhibitory effectiveness of mycelial growth in the PDA medium test, have not anti-mold effectiveness. Of all prepared preservatives in this study, only three preservatives containing dinotefuran and IPBC, or adding clove oil appeared the excellent anti-mold effectiveness.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.7-13
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• 2015

Hydrotrope-combined copper (HCC) is a copper ($Cu^{2+}$)-based algicide, which is combined with a hydrotrope that keeps copper ion in solution to improve performance. This study assessed the growth inhibition effect of HCC against Microcystis aeruginosa which is one of the most common toxic cyanobacterium in eutrophic freshwater environment. Various HCC doses, ranging from 5.5 to $550{\mu}g/L$ as $Cu^{2+}$, were applied to either BG-11 or 1/4 diluted medium with low- or high-inoculum density of M. aeruginosa. Growth inhibition was monitored based on a decrease in chlorophyll-a content in culture medium during the incubation. Results showed that HCC significantly inhibited the growth of M. aeruginosa in a dose-dependent manner. In case of 1/4 diluted BG-11 medium, HCC dose as low as $5.5{\mu}g$ $Cu^{2+}/L$ completely inhibited the production of chlorophyll-a by M. aeruginosa. It was found that HCC did not induce any significant release of microcystin-LR from M. aeruginosa. Acute toxicity of HCC was tested using Daphnia magna, and the 24-h $EC_{50}$ value was 0.30 mg/L as $Cu^{2+}$ which was much higher than the actual inhibition dose. Ames test was performed using Salmonella enterica serovar Typhimurium TA100, and HCC showed no increase in the number of revertant colonies. The result suggested that HCC does not have any mutagenic potential in the aquatic environment. In addition, no genotoxic effect of HCC was also confirmed based on the SOS ChromoTest using Escherichia coli PQ37. Therefore, HCC could be used as a relatively safe and effective pre- and post-treatment agent to control hazardous algal blooming in aquatic environments.

• Korean Journal of Organic Agriculture
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• v.24 no.2
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• pp.253-262
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• 2016

The SS (Bacillus subtilis 10%), WS (Microbial extract 70%), and DS (Sulfur 78%) agents were selected by mycelial growth inhibitory effect test against kiwifruit soft rot pathogen (B. dothidea) with 11 kinds of environment-friendly agricultural materials on PDA medium for 10 days. They showed at 94.2%, 65.2%, 58.9%, respectively. The control value of WS and SS agents were better than DS in storage experiment. It was effective SS and WS single application, DS-WS and WS-SS alternate application in the field trial.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.213-218
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• 1993

An experiment was carried out to investigate the effects of plant growth regulators on the growth and fiber yield of ramie. Gibberellin (GA) and Atonic acid were applied at the various levels of application dates, application frequencies and concentration. Stem growth of ramie increased greatly by applying GA on the meristem of shoot apex. Among three treatments of application frequencies of GA, that is, one time application at the stage of stem length with 50cm, twice applications at the stem length of 50cm and 100cm, and three times applications at stem length of 50cm, 100cm and 150cm, stem growth increased more as application frequency increased. GA application is more effective on stem growth at the later stage of growth than the earlier growth stage. GA treatment of 100 to 300 ppm is more effective on stem elongation than 50 ppm, which was due on the elongation of internodes without increase in number of nodes. One time application of GA enhanced leaf growth more or less regardless of concentration, but GA was applied more frequently, leaf growth was inhibited more at higher concentration. Fiber yield was the highest at the treatment of three times application of GA with 100 ppm. This treatment also showed the highest percentage of fiber with 5.3%, which is much higher value compared with that of control treatment with 4.6%. Atonic acid was less effective on stem elongation than GA, but it also seemed to be effective on the enhancement of fiber development.

• Journal of Korea Foresty Energy
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• v.22 no.3
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• pp.20-28
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• 2003

This study was subjected to compare seasonal changes of survival rate, relative growth rate, and chlorophyll contents of major oak tree species including Quercus acctissima, Quercus mongolica, Quercus serrata, Quercus varibilis seedlings grown in Quercus acctissima forest under different light intensities. Three light intensities were 81% of sunlight, 34% of sunlight and 21% of sunlight. In each treatment, 100 tree seedlings were planted and survival rate, growth rate, and chlorophyll contents were measured. The highest survival rate was Quercus acctissima in 73% seedlings compared with those subjected to the other tree seedlings in 45~66%. Lowest survival rate was Quercus vnriabilis seedlings in 41%. Oaks tree species of the height, the root collar diameters of the relative growth were better in the seedlings grown in 81% light intensities of full sun. But growth rates decreased rapidly in the shade treatment of 21% light intensities of full sun. Lowest chlorophyll contents(chlorophyll a, b and total) were shown at 21% light intensities of full sun, lowest light intensity treatment in this study This result is thought growth and chlorophyll contents associated with light intensity Also, Physiological characteristics has to be investigated in near future because photosynthesis and chlorophyll contents were strongly related to tree growth with long periods.

• Journal of Korean Society of Forest Science
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• v.33 no.1
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• pp.1-32
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• 1977

This study has been made to find out more effective way of vegetation establishment on severely denuded forest land from the viewpoint of soil moisture regimes. Various environmental factors were measured to estimate soil moisture conditions of different sites. Soil moisture influence on growth of over vegetations, water requirement and drought resistance were analyzed. The efficiency of water use was also reckoned at different fertility levels and different soil moisture conditions. This research is composed of field experiment and green house experiment. Field experiment includes height growth, survival and coverage analysis of cover vegetations (Robinia pseudoacacia L., Lespedeza bicolor Turcz, Arundinella hirta Tanaka var. ciliare Koidzumi.) with 4 fertility level treatments on 3 slopes (Steep: $37^{\circ}$, Moderate: $25^{\circ}$, Gentle; $17^{\circ}$) during dry season (1 April-30 June) and wet season (1 July-10 September). At the same time temperature, relative humidity and precipitation were measured to understand the environmental changes. Soil moisture conditions were measured with soil moisture meter with 24 soil cells. Green house experiment comprised height, fresh weight and dry weight measurements of cover vegetations with 4 fertility levels and 3 moisture conditions for 70 days. The results extracted from experiments are as follews. 1. Cover vegtations have 3 patterns of water requirement at the early stage of growth. a) Robinia type has high water requirement and weaker drought resistance. b) Lespedeza type has low water requirement and stronger drought resistance. c) Arundinella type has moderate water requirement and weaker drought resistance. 2. The vegetations have different optimum fertility levels in different soil moisture supply condition. a) Robinia needs a low fertility level in dry condition and a high level in wet condition. b) Lespedeza needs only low fertility level in all conditions. c) Arundinella needs a low fertility level in dry condition and a high level in wet condition. 3. The efficiency of water use (Water/1g dry weight) by fertility levels is different from one another. Robinia and Arundinella have a good efficiency at low fertility level in dry condition and at high fertility level in wet condition. Lespedeza has a good efficiency at low fertility level in all conditions. 4. $P_2O_5$ requirement of Robinia and Lespedeza is high, but that of Arundinella is low. Soil moisture condition has a great influence on $P_2O_5$ absorption in dendued forest land. Once Vegetations are established on suitable sites with optimum fertitity level according to different moisture condition, even the small amount of soil water in denuded land can he used with high efficiency and the effect of fertility treatment can be maximized.