• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.110-123
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• 2016

In order to obtain scientific information for the conservation of Utricularia japonica Makino, rare plant species, we investigated life history, phenology, growth and distribution in the east coastal region of Korea. Seven habitats of U. japonica were confirmed in this study. Turion of U. japonica rests overwinter at the bottom and ripens at the water surface and then usually germinate and sprout when the water warms in spring. A single shoot grown from turion divided into several shoots. Shoot decomposition started in October and formed a new turion at the end of the decomposed shoot. Flowering period was from early July to late October. Percentage of flowering ramets was significantly low as 6.3%. U. japonica showed the fastest growth rate from April to July, the maximum growth in August and the highest biomass in October. U. japonica tended to be concentrated in larger ramets in the water depth of 50 cm~150 cm in Cheonjin lake. The main factors affecting the growth of U. japonica were water temperature and turbidity. The establishment and growth of U. japonica in Cheonjin lake were determined by responses to water temperature with seasonal change and to light conditions caused by the different plants. These conditions affect the temporal and spatial distribution of U. japonica and population change. The findings of this study would be helpful to provide the basic information needed for the conservation and restoration of U. japonica.

• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.171-176
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• 2011

Sclerotinia homoeocarpa, the causal agent of dollar spot, is one of the most common pathogens of cool season turfgrasses in South Korea. The vegetative compatibility group (VCG) assay was carried out using nitrate-nonutilizing (nit) mutants recovered from 13 South Korean isolates with various geographical origins. The mutants were divided into four phenotypic classes based on mutation loci associated with nitrogen assimilation: nit1, nit2, nit3, and NitM. The recovered number of nit mutants greatly varied among the isolates, ranging from 0 to 15 mutants. Of the mutants isolated, nit1 and nit2 mutants were most common (80%) while NitM and nit3 were relatively rare. One dominant and four minor VCGs were determined from 18 mutant isolates tested. To study population structures of Korean S. homoeocarpa isolates and increase our understanding of its ecological and epidemiological aspects for dollar spot management on turfgrass, more generated mutants should be tested with more diverse isolate collections.

• Korean journal of applied entomology
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• v.51 no.2
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• pp.83-90
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• 2012

The effect of natural enemies on four major pests of hot pepper was tested in greenhouses. The aphids were successfully controlled by introducing three Aphidius colemani-banker plants, and releasing 23.3 wasps per $m^2$ on April 16 and 23 wasps per $m^2$ in a greenhouse of 660 $m^2$. To control thrips, Orius laevigatus was released twice, 3.0 bugs per $m^2$ at a time(May $11^{th}$ and June $12^{th}$). The thrips population was controlled within 0.3 thrips per flower during the growing season. To control two species of mites, Tetranychus kanzawai and Polyphagotarsonemus latus, and the silverleaf whitefly, Bemisia tabaci, a total of 113.7 individuals of Amblyseius swirskii were released twice(May $11^{th}$ and $30^{th}$). The densities of B. tabaci and T. kanzawai were kept within 171.0 individuals/trap and 0.8 individual/leaf, respectively. P. latus was suppressed completely twelve days after release. The cost of the released natural enemies to control the four arthropod pests in this study was 420,000 Won per 660 $m^2$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.6
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• pp.532-538
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• 1990

This experiment was carried out to establish the efficiency of crop breeding on comparison of combination methods of single, 3-way, and double crosses and combination order of 4 winter wheat which were different in origin, source, and plant types, On comparison of 4 crossing modes, there appeared the earliest heading and the highest grain yield in double cross, and decreased in 3-way. single crosses. and parents in order, There showed the significant mean squares of GCA and SCA in 4${\times}$4 diallel analysis for grain yield and yield components. Grumil and Bezostaya 1 exhibited highest GCA effect of grain yield which appeared the actual highest grain yield. There appeared the highest SCA-effect in F$_1$ (Eunpamil/Bezostaya 1) showing 4.22. Of the 3 double crosses there exhibited the highest grain yield in F$_1$ (Grumil/Eunpamil/ /Lanota/Bezostaya 1). Two single crosses for this double cross ---F$_1$ (Grumil/Eunpamil) and F$_1$ (Lancota/Bezostaya 1) --- do not revealed directly for this yield, but combined each other by chromosome switch as combination of F$_1$ (Grumil/Lancota), F$_1$(Grumil/Bezostaya 1), F$_1$(Eunpamil/Lancota) and F$_1$(Eunpamil/Bezostaya 1) which appeared the higher grain yields and SCA-effects. Of the six 3-way crosses. F$_1$ (Lancota/Bezostaya 1/ /Eunpamil) expressed the highest grain yield. Its combinations were F$_1$ (Lancota/Eunpamil) and F$_1$ (Bezostaya 1/Eunpamil) combined by chromosome switch, which its grain yield and SCA-effect were higher.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.98-98
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• 2017

Leaf senescence is the process of aging in plants. Chlorophyll degradation during leaf senescence has the important role translocating nutrients from leaves to storage organs. The functional stay-green with slow leaf yellowing and photosynthesis activity maintenance has been considered one of strategy for increasing crop productivity. Here, we have identified two QTLs on chromosome 9 and 10 for leaf senescence with chlorophyll content of RIL population derived from a cross between Hanareum 2, early leaf senescence Indica-type variety, and Unkwang, delayed leaf senescence Japonica variety. Among these QTLs, we chose qPLS1 QTL on chromosome 9 for further study. qPLS1 was found to explain 14.4% of the total phenotypic variation with 11.2 of LOD score. Through fine-mapping approach, qPLS1 QTL locus was narrowed down to about 25kb in the marker interval between In/del-4-7-9 and In/del-5-9-4. There are 3 genes existed within 25kb of qPLS1 locus: LOC_Os09g36200, LOC_Os09g36210, and LOC_Os09g36220. Among these genes, transcript level of LOC_Os09g36200 was increased during the leaf senescence stage and the expression level of LOC_Os09g36200 in Indica was higher than in Japonica. Finally, we chose LOC_Os09g36200 as candidate gene and renamed it as OsPLS1-In and OsPLS1-Jp from Indica- and Japonica-type rice, respectively. OsPLS1-In and OsPLS1-Jp overexpressing transgenic plants showed both early leaf senescence phenotype. These results indicate that OsPLS1 functions in chlorophyll degradation and the difference of expression level of OsPLS1 cause the difference of leaf senescence between Indica and Japonica in rice.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.402-407
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• 2013

Bermudagrass (Cynodon dactylon.) is one of the most difficult weedy species to control in turfgrass because it's high tolerant to various environmental and management stresses. This experiment was performed to find the integrated weed management including cultural practices to suppress bermudagrass in Zoysiagrass matrella (L) Merr. As results, two sequential applications of Fluazifop-P-butyl 0.05 ml $m^{-2}$ + Triclopyr-TEA 0.5 ml $m^{-2}$ and Fenoxaprop-P-ethyl 0.1 ml $m^{-2}$ + Triclopyr-TEA 0.5 ml $m^{-2}$ applied on 20 days intervals were evaluated the primary option for bermudagrass suppression and turfgrass injury was acceptable in zoysiagrass. In both treatments, turf injury was observed during 30days after the first application and almost recovered at 40days. While Fenoxaprop-Pethyl 0.1 ml $m^{-2}$ + Triclopyr-TEA 0.5 ml $m^{-22}$ were lightly phytotoxic to zoysiagrass in chlorophyll content test, there was no growth inhibition of zoysiagrass. Verticut practice (4 mm depth) just before herbicides application where zoyisagrass is contaminated with bermudagrass was not helpful to reduce turf injury in this experiment. However, alone verticut management was utilized to decrease about 12-14% bermudagrass population. Thus the application of Fenoxaprop-P-ethyl 0.1 ml $m^{-2}$ + Triclopyr-TEA 0.5 ml $m^{-2}$ which are permitted for turfgrass after zoysiagrass is perfectly recovered from turf injury by verticut practice should be utilized for bermudagrass reduction in zoysiagrass.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.6
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• pp.727-735
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• 2007

The use of water by cities is increasing owing to industrialization, the concentration of population, and the enhancement of the standard of living. Accordingly, the amount of waste water is also increasing, and the degree of pollution of the water system is rising. In order to solve this problem, it is necessary to remove organisms and suspended particles as well as the products of eutrophication such as nitrates and phosphates. This study developed a high-end treatment engineering solution with maximum efficiency and lower costs by researching and developing a advanced treatment engineering solution with the use of Biosorption. As a result, the study conducted a test with a $50m^3/day$ Pilot Scale Plant by developing treatment engineering so that only the secondary treatment satisfies the standard of water quality and which provided optimal treatment efficiency along with convenient maintenance and management. The removal of organisms, which has to be pursued first for realizing nitrification during the test period, was made in such a way that there would be no oxidation by microorganisms in the reactor while preparing oxygen as an inhibitor for the growth of microorganism in the course of moving toward the primary settling pond. The study introduced microorganisms in the endogeneous respiration stage to perform adhesion, absorption, and filtering by bringing them into contact with the inflowing water with the use of a sludge returning from the secondary settling pond. Also a test was conducted to determine how effective the microorganisms are as an inner source of carbon. The HRT(Hydraulic Retention Time) in the nitrification tank (aerobic tank) could be reduced to two hours or below, and the stable treatment efficiency of the process using the organisms absorbed in the NAR reactor as a source of carbon could be proven. Also, given that the anaerobic condition of the pre-treatment tank becomes basic in the area of phosphate discharge, it was found that there was excellent efficiency for the removal of phosphate when the pre-treatment tank induced the discharge of phosphate and the polishing reactor induced the uptake of phosphate. The removal efficiency was shown to be about 94.4% for $BOD_5$. 90.7% for $COD_{Cr}$ 84.3% for $COD_{Mn}$, 96.0% for SS, 77.3% for TN, and 96.0% for TP.

• Journal of Environmental Science International
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• v.18 no.4
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• pp.463-471
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• 2009

A study on vegetation in the Mangyeong River and Dongjin River basins and the surrounding regions of the Saemangeum Reclaimed Land was conducted in a series of efforts to determine the expected ecological changes in the salt marshes, to restore their vegetation, to explore the restoring force of halophyte, to examine the community mechanism and, ultimately, to rehabilitate marshy land vegetation along the lakeside, coastal dune and salt marshes of the Saemangeum Project Area. The findings of the study may be summed up as follows: Five species such as Suaeda japonica, Salicornia herbacea, Atriplex gmelini, Aster tripolium and Suaeda asparagoides that are mostly distributed in the estuary of the Saemangeum Reclaimed Land were analyzed to examine the mechanism of halophyte to maintain their community. To find out the strategies of plants for survival and the cause of forming community structure, a research was made as for appearance ratio of biomass, root lengths and germination. With regard to biomasses of halophyte, the biomass of Suaeda japonica increases rapidly, while Salicornia herbacea adopts a strategy of unstable growth pattern by which the biomass increases slowly in parallel with its slow speed of growth since initial appearance of young sapling. In contrast, Suaeda asparagoides, Atriplex gmelini and Aster tripolium choose to adapt themselves to environment promptly by being transformed into life form of annual or biennial plant, a pattern that is presumed to be favorable and stable for survival in the later stage of growth. In short, there is a sharp distinction among the 5 species: i.e. Suaeda japonica that begins to grow fast in the length of surface and underground section but slows down from the mid-stage on; Salicornia herbacea that grows slowly in the beginning step but starts to step up from the middle onward; Atriplex gmelini and Aster tripolium growing slowly in the initial stage but fast later on; and Suaeda asparagoides that turns from the constant growth in the beginning to rapid growth in the later period. The outcomes of the analysis into status of growth and influencing factors of Suaeda japonica in the sowing field that is most widely prevalent in the Saemangeum Reclaimed Land as a sort of ecological pioneer in the salt marshes showed that the average size of grass lands, density and number of individuals increase in the natural sowing field as well as in the plowing field regardless of their physical as well as physico-chemical features of the soil as the season progresses from June to October of a year.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.10
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• pp.1424-1436
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• 2013

The objective of this study was to investigate the effect of banana flower powder (BAFLOP) supplementation on gas production kinetics and rumen fermentation efficiency in in vitro incubation with different ratios of roughage to concentrate in swamp buffalo and cattle rumen fluid. Two male, rumen fistulated dairy steers and swamp buffaloes were used as rumen fluid donors. The treatments were arranged according to a $2{\times}2{\times}3$ factorial arrangement in a Completely randomized design by using two ratios of roughage to concentrate (R:C; 75:25 and 25:75) and 3 levels of BAFLOP supplementation (0, 2 and 4% of dietary substrate) into two different kinds of rumen fluid (beef cattle and swamp buffalo). Under this investigation, the results revealed that the rumen ecology was affected by R:C ratio. The pH declined as a result of using high concentrate ratio; however, supplementation of BAFLOP could buffer the pH which led to an improvement of ruminal efficiency. BAFLOP supplementation affected acetic acid (C2) when the proportion of concentrate was increased. However, there were no effect on total volatile fatty acid (TVFA) and butyric acid (C4) by BAFLOP supplementation. The microbial community was affected by BAFLOP supplementation, especially the bacterial population. As revealed by real-time PCR, the populations of F. succinogenes and R. albus were reduced by the high concentrate treatments while that of R. flavafaciens were increased. The populations of three dominant cellulolytic bacteria were enhanced by BAFLOP supplementation, especially on high concentrate diet. BAFLOP supplementation did not influence the ammonia nitrogen ($NH_3$-N) concentration, while R:C did. In addition, the in vitro digestibility was improved by either R:C or BAFLOP supplementation. The BAFLOP supplementation showed an effect on gas production kinetics, except for the gas production rate constant for the insoluble fraction (c), while treatments with high concentrate ratio resulted in the highest values. In addition, BAFLOP tended to increase gas production. Based on this study, it could be concluded that R:C had an effect on rumen ecology both in buffalo and cattle rumen fluid and hence, BAFLOP could be used as a rumen buffering agent for enhancing rumen ecology fed on high concentrate diet. It is recommended that level of BAFLOP supplementation should be at 2 to 4% of total dry matter of substrate. However, in vivo trials should be subsequently conducted to investigate the effect of BAFLOP in high concentrate diets on rumen ecology as well as ruminant production.

• Journal of Microbiology and Biotechnology
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• v.26 no.12
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• pp.2159-2170
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• 2016

Many plant-pathogenic bacteria are dependent on quorum sensing (QS) to evoke disease. In this study, the population of QS and quorum quenching (QQ) bacteria was analyzed in a consecutive monoculture system of Pseudostellaria heterophylla. The isolated QS strains were identified as Serratia marcescens with SwrIR-type QS system and exhibited a significant increase over the years of monoculture. Only one QQ strain was isolated from newly planted soil sample and was identified as Bacillus thuringiensis, which secreted lactonase to degrade QS signal molecules. Inoculation of S. marcescens to P. heterophylla root could rapidly cause wilt disease, which was alleviated by B. thuringiensis. Furthermore, the expression of lactonase encoded by the aiiA gene in S. marcescens resulted in reduction of its pathogenicity, implying that the toxic effect of S. marcescens on the seedlings was QS-regulated. Meanwhile, excess lactonase in S. marcescens led to reduction in antibacterial substances, exoenzymes, and swarming motility, which might contribute to pathogensis on the seedlings. Root exudates and root tuber extracts of P. heterophylla significantly promoted the growth of S. marcescens, whereas a slight increase of B. thuringiensis was observed in both samples. These results demonstrated that QS-regulated behaviors in S. marcescens mediated by root exudates played an important role in replanting diseases of P. heterophylla.