• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.409-416
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• 1999

Microwave extraction system equipped with closed vessels was applied to confirm its capability of extracting ginseng solubles including saponin, which was monitored to optimize extraction con ditions by response surface methodology. Total yield increased with the decrease in particles size and more extraction steps. Soluble components were completely extracted by operating the system within 6 min per one step, which should be repeated by 3 or 4 times. Optimized conditions for maxi mum extraction of response variables(total yield, crude saponin) were 40~50% of ethanol concentration, about 140oC of extraction temperature, and within 6 min of the extraction time. The extraction effi ciency of total yield was dependent on the decrease of ethanol concentration, while crude saponin content was favored on the higher degree of ethanol concentration. According to the temperature guideline, below 90oC of extraction temperature, the optimal ranges of extraction conditions were predicted as 30~50% of ethanol concentration and 2.5~6.5 min of extraction time. Estimated values of total yield and crude saponin were in good agreement with experimental values.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.36-37
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• 2004

$\alpha$-Chloromethylnaphthalene is a valuable compound for obtaining of the plant growing stimulator - $\alpha$-napthylacetic acid. Chloromethylation of naphthalene by paraformaldehyde in the presence of glacial acetic acid, phosphoric and hydrochloric acids at temperature 80-85$^{\circ}C$ and duration - 6 hours the $\alpha$-chloromethyl-naphthalene yield was 55-57%. Using Box-Wilson method for mathematical planning of experiment carried out optimization of its synthesis for purpose increasing $\alpha$-chloromethylnaphthalene yield. Preliminary, one - factor experiments were carried out for selecting independence main parameters influencing on the synthesis. A full factor experiment of 2$^3$with extended matrix of planning was used for optimization. Aiming to increase the $\alpha$-chloromethylnaphthalene yield, the obtained mathematical model was used for program of sharp raising on the reply surface. The received optimal conditions for the $\alpha$-chloromethylnaphthalene synthesis were selected as following: molar ratio of naphthalene - parapfsormaldehyde of 1 : 2; temperature -105$^{\circ}C$; duration of the reaction -3 hours. The yield of $\alpha$-chloromethylnaphthalene under these optimal conditions was 75 %.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.3
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• pp.141-147
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• 2019

The purpose of this study was to determine the effect of waterlogging duration on the growth characteristics and productivity of forage corn at different growth stages under paddy field conditions. Treatments consisted of waterlogging at two growth stages (V7 or V14) for four waterlogging durations (no waterlogging, 48 hours, 72 hours, and 96 hours, respectively). The V14 growth stage was more vulnerable to waterlogging than the V7 stage. Among the waterlogging durations, the lodging score increased at 48 hours. The stem height of forage corn decreased with the increase in waterlogging duration at the different growth stages (V7 and V14). Increase in waterlogging duration reduced the stem dry matter yield, ear dry matter yield, and total dry matter yield at both growing stages (V7 and V14). The waterlogging treatments at the V14 stage affected ear dry matter yield more than those at the V7 growing stage. Thus, the management of forage corn under paddy field conditions must be strengthened during early (V7) and grain fill stages (V14). When waterlogging occurs, surface and subsurface drainage should be implemented within 48 hours to control (no waterlogging) the groundwater level and, thus, minimize economic losses due to forage corn damage.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.594-597
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• 2014

Crop yields depend on the limiting factor of crop growth; Liebig law of minimum. Identifying the kind and the necessary amount of the limiting factor is essential to increase crop yield. Although nitrogen is the most essential nutrient, N application does not always bring about yield increases when other elements are limiting in rice cultivation. Two experiments were compared to elucidate the effect of soil testing on rice yield response to N level. The one was an experiment about yield response of 3 rice cultivars to 7 levels of N application, which was conducted from 2003 to 2004 in 25 farmer's fields without ameliorating soil conditions by soil testing and the other was a demonstration experiment on N fertilizer recommendation equation by 0, 0.5, 1.0, and 1.5 times of N recommended level in 5 soil types from 30 fields after ameliorating soil conditions by soil testing. The N response patterns of the experiments conducted without soil testing showed a Mitscherlich pattern in some cultivars and soil types, but did not in the others. The N response patterns of the demonstration experiment showed a Mitscherlich pattern in all soil types. Because these results indicated that N was the minimum nutrient in the demonstration experiment by ameliorating soil conditions with soil testing, but not in the other experiment without soil testing, the supply of minimum nutrients by soil testing could increase the efficiency of N-fertilization.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1300-1307
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• 2007

This study assessed the possible role of different traits in selected plant growth-promoting rhizobacteria (PGPR) for improving wheat growth and yield under natural conditions. Rhizobacteria exhibiting 1-aminocyclopropane-1-carboxylate (ACC)-deaminase activity were isolated and screened for their growth-promoting activity in wheat under axenic conditions. Five isolates belonging to Pseudomonas and one Burkholderia caryophylli isolate that showed promising performances under axenic conditions were selected and characterized for in vitro ACC-deaminase activity, chitinase activity, auxin production, P solubilization, and root colonization. These isolates were then used as inocula for wheat cultivated under natural conditions in pot and/or field trials. Significant increases in root elongation, root weight, tillers per pot, 1,000-grain weight, and grain and straw yields were observed in response to inoculation with PGPR in the pot trials. Inoculation with these PGPR was also effective under field conditions and increased the wheat growth and yield significantly. However, the efficacy of the strains was inconsistent under the axenic, pot, and field conditions. Pseudomonas fluorescens ($ACC_{50}$), which exhibited a relatively high in vitro ACC-deaminase activity, chitinase activity, auxin production, and P solubilization and more intensive root colonization, was the most efficient isolate under the field conditions. Therefore, these results demonstrated that ACC-deaminase activity is an efficient parameter for the selection of promising PGPR under axenic conditions. However, additional traits of PGPR, including auxin production, chitinase activity, P solubilization, and root colonization, are also important for selecting PGPR as biofertilizers.

• Korean Journal of Food Science and Technology
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• v.51 no.2
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• pp.188-191
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• 2019

In this study, the poor electro-transformant yield of large DNA in bifidobacteria was improved by increasing the DNA concentration, which was amplified by enhancing electroporation conditions: treating the cell wall weakening agent and cell membrane permeabilizing molecule as well as changing the electrical parameter. In the enhanced conditions, the electroporation frequency increased from 15 to 71 times compared to the initial conditions at the same DNA concentration. As the DNA concentration increased, the difference in the electroporation frequency between the two conditions became greater, and the curve of the enhanced conditions seemed to be saturated with a DNA concentration over $4{\mu}g$. The present study provided a clue to the recovery of the electroporation frequency with large DNA and formulated the relationship between the DNA concentration, the DNA size and the electroporation frequency in bifidobacteria. Therefore, this study will contribute to the expansion of molecular genetic studies of bifidobacteria.

• Korean Journal of Agricultural and Forest Meteorology
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• v.19 no.2
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• pp.54-61
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• 2017

Rice yield of South Korea in 2015 was the highest in last 30 years. The future direction of food policy in South Korea can be determined depending on whether the historically highest yield in 2015 can be continued or just one-off event. Therefore, it is necessary to understand whether such a high yield as 2015 can be reoccurred and how often it can occur. This study used the yield monitoring data from National Institute of Crop Science, Rural Development Administration and the meteorological data provided by Korea Meteorological Administration to identify the weather conditions, which could cause high yield, and how often these conditions occurred in the past. Our results showed that significantly high yield in 2015 could occur only when the mean sunshine hours of July and the mean sunshine hours from the end of August to early September are 5.1 hours and 6 hours, respectively. The probability of satisfying these weather conditions was 8/35 (23%) over the past 35 years. And the probability of successive high yield for two years was 1/35 (2.9%). The probability of recurrence of high yield within the next 5 years or 10 years after high yield was 4/35 (11.4%).

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.19-19
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• 2017

The indica ${\times}$ japonica rice (Oryza sativa L.) cultivars released in Japan since 1980 are high-yielding. However, occasionally in these cultivars their high yield potentials cannot be realized, particularly depending on climate conditions. The objectives of this study were to identify the reason for yield instability and the critical yield component factor causing lower grain yield in these high-yielding cultivars. Standard-yield japonica, high-yielding japonica-dominant, and indica-dominant cultivars were grown in western Japan. Rough grain yield (RY) in these high-yielding cultivars ranged from 450 to $980g\;m^{-2}$, and was positively correlated with potential grain yield (PRY). By fluctuations of solar radiation, RY changed with spikelet number (SNO), and SNO was correlated with cumulative radiation during the panicle formation period of 30 days before heading. Even if higher SNO was achieved under higher radiant conditions, RY was lower than PRY. The lower grain-filling in plants bearing higher SNO resulted from a lower filling percentage of spikelets (%F, RY/PRY), and %F was strongly correlated with spikelet fertility (%S) across all cultivars. %S was highly influenced by cumulative radiation per PRY during pollen development and establishment around heading. Inhibition of assimilation by leaf removal lowered %S. Conversely, stem thinning and removal of upper panicles around heading increased %S in spikelets of the lower part of the panicle in which sterility was higher. These results suggest that limitation of assimilate-supply due to low irradiance at the spikelet-formation and flowering stages restrains the potential of the high-yielding cultivars, depending on reduction of SNO and %S, respectively.

• Korean Journal of Pharmacognosy
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• v.49 no.1
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• pp.65-69
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• 2018

Torilin is a major sesquiterpene of Torilis japonica (Umbelliferae) fruits and known to be a melanogenesis inhibitor. Extraction conditions are important factor for the efficient preparation to save cost and time in economic aspects. For this reason, this study was conducted to optimize the extraction condition for maximal yield of torilin. For optimization, extraction factors such as extraction solvent, extraction temperature and sample/solvent ratio were tested and optimized for maximum yield of torilin using response surface methodology with Box-Behnken design (BBD). The optimal condition was obtained as a EtOAc concentration in MeOH of 31.8%, an extraction temperature at $30.3^{\circ}C$ and a sample/solvent ratio, 1000 mg/2 ml. The torilin yield under optimal conditions was found to be 9.9 mg/g dried samples, which were well-matched with the predicted value of 10.4 mg/g dried samples. These results will provide useful information about optimized extraction conditions for the development of torilin as cosmetic therapeutics to reduce skin hyperpigmentation.

• Korean Journal of Pharmacognosy
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• v.53 no.4
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• pp.202-206
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• 2022

Salidroside is a major phenolic glycoside of Acer tegmentosum (Aceraceae) and known to be a hepatoprotective compound. Extraction conditions are one of the most important factors to save time and cost from an economic point of view. For this reason, this study was conducted to optimize the extraction condition for maximum yield of salidroside. For optimization, three extraction factors such as ethanol concentration (%), extraction temperature (℃), and solvent to material ratio (mg/mL) were tested and optimized for maximum yield of salidroside using response surface methodology (RSM). The optimal condition was obtained as an ethanol concentration of 53.4%, an extraction temperature at 67.11℃ and a solvent to material ratio (mg/mL), 195.55 mg/ml. The salidroside yield under optimal conditions was found to be 1.59 mg/g dried samples, which were well-matched with the predicted value of 1.56 mg/g dried samples. These results will provide useful information about optimized extraction conditions for the development of salidroside as hepatoprotective therapeutics.