• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1129-1134
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• 2009

Increasing application of nanotechnology highlights the need to clarify nanotoxity and nanoparticles characterization. However, few researches have focused on phytotoxicity of nanoparticles. This study was to examine phytotoxicity on Cumumis sativus seedling and the dissolution of Zn, ZnO nanoparticles in hydroponic culture system. Results of this study; characteristics of Zn, ZnO nanoparticles are more aggregated in nutrient solution than deionized water. C. sativus biomass significantly reduced in the nutrient solution were higher than 100 mg/L, and Zn toxicity showed $Zn^{2+}$> Zn> ZnO NPs. Results of transmission electron microscopy images, Zn and ZnO nanoparticles greatly adhered onto the root cell wall and nanoparticles were observed in the root cell.

• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1045-1059
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• 2021

Various abiotic stressors like drought, salinity, temperature, and heavy metals are major environmental stresses that affect agricultural productivity and crop yields all over the world. Continuous changes in climatic conditions put selective pressure on the microbial ecosystem to produce exopolysaccharides. Apart from soil aggregation, exopolysaccharide (EPS) production also helps in increasing water permeability, nutrient uptake by roots, soil stability, soil fertility, plant biomass, chlorophyll content, root and shoot length, and surface area of leaves while also helping maintain metabolic and physiological activities during drought stress. EPS-producing microbes can impart salt tolerance to plants by binding to sodium ions in the soil and preventing these ions from reaching the stem, thereby decreasing sodium absorption from the soil and increasing nutrient uptake by the roots. Biofilm formation in high-salinity soils increases cell viability, enhances soil fertility, and promotes plant growth and development. The third environmental stressor is presence of heavy metals in the soil due to improper industrial waste disposal practices that are toxic for plants. EPS production by soil bacteria can result in the biomineralization of metal ions, thereby imparting metal stress tolerance to plants. Finally, high temperatures can also affect agricultural productivity by decreasing plant metabolism, seedling growth, and seed germination. The present review discusses the role of exopolysaccharide-producing plant growth-promoting bacteria in modulating plant growth and development in plants and alleviating extreme abiotic stress condition. The review suggests exploring the potential of EPS-producing bacteria for multiple abiotic stress management strategies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.265-269
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• 2009

Technology development for sufficient dry matter production of Chinese milk vetch (CMV) is most important in CMV-rice cultivation system in order to provide sufficient nutrients to rice plants. However, when the CMV plants are dominated by the weed, especially Alopecurus aequalis, the CMV growth could be reduced due to light and nutrient competition. In addition, A. aequalis is potential host of the rice dwarf virus disease. Therefore, control of A. aequalis is necessary to enhance the biomass production of CMV plants when CMV stands are insufficient. The use of chemical like sethoxydim (20%, ai) showed the highest control rate of 84% at early stage and was reduced as application was delayed. A. aequalis control did not change the CMV seedling stand before and after herbicide treatment and the reseeding stand in fall was rather increased 2.2 to 2.6 times. On the other hand, in untreated control, the CMV stand at May 15 and reseeding stand in fall was significantly reduced as compared with the before herbicide treatment. Control of A. aequalis increased the CMV dry matter production by 164% for 50% CMV coverage rate and 63% for 25% CMV coverage rate. This is equivalent to $12.3{\sim}16.4\;kgN$/10a which is greater than the recommended nitrogen rate of 9kg/10a. The result indicates that the control of A. aequalis is an efficient way to enhance dry matter production in CMV-rice cultivation system especially when CMV stand is poor.

• Journal of Korean Society of Forest Science
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• v.104 no.1
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• pp.90-97
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• 2015

The objective of this study was to find optimal amount of fertilization of container seedling production for Zelkova serrata, Ulmus parvifolia, Betula costata and Tilia amurensis. To reach our goal, we measured root collar diameter (RCD), height, biomass and seedling quality index (SQI) of container seedlings of four deciduous hardwood species grown at three different fertilization treatments ($0.5g{\cdot}L^{-1}$, $1.0g{\cdot}L^{-1}$ and $2.0g{\cdot}L^{-1}$). Z. serrata seedlings grown at $2.0g{\cdot}L^{-1}$ fertilization and B. costata seedlings grown at $0.5g{\cdot}L^{-1}$ fertilization showed the highest RCD, height, biomass and SQI. The RCD and height of U. parvifolia and T. amurensis seedlings showed no significant differences by fertilization treatments. Seedlings of two species at $0.5g{\cdot}L^{-1}$ fertilization showed the lowest SQI, however, SQI at 1.0 and $2.0g{\cdot}L^{-1}$ fertilization treatments were not significantly different. Based on these results, it is appeared that container seedlings of Z. serrata at minimum $2.0g{\cdot}L^{-1}$ fertilization, U. parvifolia and T. amurensis at $1.0g{\cdot}L^{-1}$ fertilization and B. costata at maximum $0.5g{\cdot}L^{-1}$ fertilization were optimal nutrient conditions. Practice of optimal fertilization rate will make us get better quality seedlings and reduction of production costs in the container nursery system as well as good field performances with higher survival rate after planting.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.185-190
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• 2018

This study was conducted to investigate the optimum electrical conductivity (EC) levels of nutrient solution for growth of mother plants and increasing occurrence of daughter plants of strawberry ($Fragaria{\times}ananassa$ Duch. cv. Maehyang) using hydroponics. The mother plants of strawberry were transplanted in cultivation pot ($61{\times}27{\times}18cm$) filled with coir medium on March 22, 2017. Nutrient solution was supplied by the drip tape at $0.6dS{\cdot}m^{-1}$ of EC levels for rooting during 11 days. After rooting, the mother plants of strawberry was treated at the EC levels of 0.6, 1.2 or $1.8dS{\cdot}m^{-1}$, respectively. Growth characteristics, such as mother plants and daughter plants of strawberry were measured at 100 days after transplanting. The plant height of mother plant was significantly higher at $0.6dS{\cdot}m^{-1}$ treatment, and the crown diameter of mother plant was significantly greater at $1.8dS{\cdot}m^{-1}$ treatment. The fresh and dry weights of shoot were higher at both 0.6 and, $1.2dS{\cdot}m^{-1}$ treatments. The number of runners was not significantly different in all treatments. The fresh and dry weights of runner were heavier at $0.6dS{\cdot}m^{-1}$ than other treatments. The number of daughter plants was the highest, 16.7 at the $1.2dS{\cdot}m^{-1}$ treatment. However, the fresh and dry weights of third daughter plant were the heaviest at $0.6dS{\cdot}m^{-1}$ treatment. Although the daughter plants were a large of production at $1.2dS{\cdot}m^{-1}$ treatment, the low EC levels of strawberry were positive in terms of seedling quality during nursery. These results indicated that growth of mother plant and occurrence of daughter plants were greater at the EC $0.6dS{\cdot}m^{-1}$ nutrient solution for hydroponic cultivation of 'Maehyang' strawberry during nursery period.

• Journal of Plant Biology
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• v.34 no.2
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• pp.93-100
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• 1991

Walnut (Juglans regia L.) is a common cultivated and wild deciduous tree in the temperate regions of Pakistan and elsewhere. A bare or poor understorey of wild or cultivated species is frequently observed beneath and around it. Soil analysis indicated insignificant differences in nutrient status of soils taken from areas with or without walnut influence. Field investigations revealed that the height, shoot, fresh and dry weight of potato, turnip, corn and bean significantly decreased in the walnut-influenced parts of the field compared to their counter-parts in the same field but without walnut influence. Aqueous extracts from various parts, shoot litter, natural rain leachates and soil collected from beneath walnut significantly reduced the germination, early seedling growth, fresh and dry weight, and moisture contents of corn, turnip and bean in various laboratory experiments. Ferulic, p-coumaric, caffeic, vanillic, jJ-hydroxybenzoic, chlorogenic and gallic acid were identified as the possible allelopathic substances in the aquous extracts and rain leachates of the walnut tree. The findings suggest that the observed poor growth of crops is due to allelopathic effects of walnut.walnut.

• Journal of Environmental Science International
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• v.25 no.8
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• pp.1051-1056
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• 2016

The growth characteristics of Paeonia ostii 'Fengdan' seedlings roots in response to trichokonins-spray treatment were investigated in this study. One-year-old seedlings of P. ostii 'Fengdan' were potted in plastic cups containing garden mold and grown under field conditions. The results showed that application of trichokonins significantly promoted root growth in P. ostii 'Fengdan' seedlings. The total root projection area, total root surface area, total root volume, total root length, root number and root diameter of seedlings treated with 0.25 mg/L trichokonins were higher by 141.70, 116.59, 119.44, 55.97, 348.88 and 127.78%, respectively, than that of the control. Thus, the results supported the hypothesis that good growth condition for roots could directly improve their nutrient absorption and utilization efficiency, promoting plant growth and development.

• The Plant Pathology Journal
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• v.24 no.1
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• pp.63-66
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• 2008

The fermentation broth (FB) of Streptomyces griseofuscus 200401 isolated from non-farming soil showed antagonistic activity against powdery mildew fungus both in melon leaf/seedling assay and in field trials. The FB of S. griseofuscus 200401 was tested at different concentrations. In primary test, the control value of 2-fold diluted FB of S. griseofuscus 200401, compared to control, reached to 82.8%. The protective activity recorded 80.5% in 2-fold dilution of FB. The effect was reduced to 28.9% in high dilution (100-fold) treatment. The curative effect was relatively lower than protective activity. In field test, the antifungal activities of S. griseofuscus 200401 remained low in blocks sprayed with 100-fold diluted FB and the control values were 15.2 and 15.9% in 2005 and 2006, respectively. However, the activities were as high as 65% and 67.3% in the blocks treated with 2-fold dilution of FB during the same period.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.1
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• pp.31-40
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• 2011

This study was conducted to research how UCD(Ultra Constant Discharge) lamp lighting affects plant cultivation. To get the results within a short time, lettuce seedling was selected as a plant and nutrient hydroponic beds were used in a dark room for 100% artificial lighting. Two beds were installed for same distance lighting condition with UCD lamp and Hi-pressure Sodium lamp each and another two beds were installed for same light intensity condition with each type of lamp. After 15 days of cultivation, for both conditions, the yields under UCD lamp were weighed more than that under Hi-pressure Sodium lamp. The result can be analyzed that the spectrum of UCD lamp having near sunlight characteristic is much superior to that of Hi-pressure Sodium lamp having a line spectrum characteristic on yellow and red wavelengths for plant cultivation.

• Journal of Bio-Environment Control
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• v.24 no.1
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• pp.13-20
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• 2015

This study was conducted to evaluate influence of short-term application of abscisic acid (ABA) in nutrient solution on growth and drought tolerance of tomato seedlings. The treatments included four ABA concentrations (0.5, 1, 2, $3mg{\cdot}L^{-1}$) and control (non-treatment) were applied to the nutrient solution in a hydroponic system. On the $5^{th}$ and $10^{th}$ day after growing in the nutrient solution containing ABA, seedlings were transferred to -5 bars of PEG-8000 in a growth chamber to induce water stress. Except for stem diameter and fresh and dry weight of root, there were no statistical differences in other growth parameters among control, 0.5 and $1mg{\cdot}L^{-1}$ of ABA treatments. Seedlings growths were strongly inhibited in nutrient solution containing 2 and $3mg{\cdot}L^{-1}$ of ABA. The root growth such as fresh and dry weigh of root, total root surface area, and average root diameter was slightly enhanced in $1mg{\cdot}L^{-1}$ of ABA treatment. The elevation of ABA concentrations in nutrient solution resulted in the decrease in transpiration rate and increase in stomatal diffusive resistance and leaf temperature of tomato seedlings. The initiations of seedling wilting after treating in -5 bars of PEG were delayed from 10 hrs in control to 30 hrs in ABA applied treatments. Additionally, the high percentages of recovered seedlings were observed in 0.5 and $1mg{\cdot}L^{-1}$ of ABA treatments after re-irrigation. Therefore, short-term application of $1mg{\cdot}L^{-1}$ of ABA in the nutrient solution stimulated the root growth and drought tolerance of tomato seedlings by delaying the start time of wilting point and enhancing the recovery after re-irrigation.