• Korean Journal of Agricultural and Forest Meteorology
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• v.26 no.2
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• pp.103-113
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• 2024

The effect of harvesting time on the growth, marketable tuber yield, and tuber quality of spring potato (Solanum tuberosum L. cv. Dami) were analyzed in the southern paddy fields in order to determine the optimal harvesting time. At 30-50 days after flowering, the total and marketable tuber yields of spring potato reached their maxima and commercial tuber rate was also high. External defects such as tuber malformation or crack did not occur until 40 days after flowering, but after that, secondary growth such as shooting appeared. Among the nutrient compositions of tubers, carbohydrate content accounted for more than 60% of tuber dry weight without significant difference among harvesting times until 50 days after flowering. The crude protein content decreased slightly as the harvesting time was delayed. However, the mineral nutrient content of tubers decreased with delaying harvesting time and was lowest at 30-40 days after flowering. Therefore, the optimal harvesting time of spring potato was judged to be 30-40 days after flowering, when marketable tuber size and quality were great as less affected by high temperature or waterlogging under natural environmental conditions.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.100-109
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• 2006

This study evaluated the effects of water velocity, substrates, and phosphorus concentrations on the growth of filamentous periphytic algae (FPA) in the two types of artificial channel systems using treated wastewater. Controlled parameters included 5 ${\sim}$ 15 cm $s^{-1}$ for the water velocity; 10 and 20 mm wire meshes, natural fiber net, gravel and tile for the substrates: and 0.05 ${\sim}$ 1.0 mgP $L^{-1}$ for the P concentration. Algal growth rate of FPA was compared using both chi. a and dry weight change with time. Under the controlled water velocity range, the growth of FPA increased with the velocity, but the maximum growth rate was shown in the velocity of 10 cm $s^{-1}$. The substrate that showed the maximum growth of FPA differed between the artificial channel and indoor channel, due to the influence of suspended matters which caused the clogging of the meshed substrates. Under the controled range of P concentration, the growth rates of all three FPA species (Spirogyra turfosa, Oedogonium fovelatum, Rhizoclonium riparium) increased with the P increase, but they showed the differential growth rates among different P concentrations. The results of this study suggest that under the circumstance having an large amount of nutrients FPA develop the biomass rapidly and that even a little increase over the threshold velocity causes the detachment of filamentous periphytic algae. Thus, FPA dynamics in eutrophic streams, such as those receiving treated wastewater, seem to be sensitive to the water velocity. On the other hand, detached algal filaments could deteriorate water quality and ecosystem function in receiving streams or down-stream, and thus they need to be recognized as an important factor in water quality management in eutrophic streams.

• Journal of Korean Society of Forest Science
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• v.78 no.3
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• pp.314-322
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• 1989

For the improvement of nursery condition and the study of eco-physiological characteristics of Pinus koraiensis(2-2) seedlings, the primary productivity was investigated and the growth characteristics and their correlationship were analyzed from May to September in 1987. Seedlings used in this study were grown at the nursery of Experimental Forestry of Kyung Hee Univ. The installation of experimental plots were divided into control plot (100%), 63%, 37% and 19% relative light intensity, and each relative light intensity plots were split into $15{\times}15/m^2$, $12{\times}12/m^2$, $9{\times}9/m^2$ and $6{\times}6/m^2$ plnting density by randomized black design method. To take into account the edge effect of plant population, material were selected from each plot by random sampling at 30 days interval. Each sampled material was divided into leaf and stem drived in a drying oven at the temperature of $85^{\circ}C$ until it had constant weight and weighed. and leaf area was surveyed. Growth analysis for RGR and NAR was done by Blackman method and correlation coefficient were investigated between RGR and NAR by analyzing the dry matter production and growth characteristics of the material, cultivated on the experimental nursery under the condition of different treatment the obtained result were as follows : 1. The increasing rate of dry matter was similar at early stage of growth, but not at late stage. 2. Leaf area growth was the maximum value at 63% relative light intensity and the minimum at 19% RLI 3. The value of RGR was the highest on June under $6{\times}6/m^2$ planting density in 63% relative light intensity, the lowest on September under $12{\times}12/m^2$ of 19% relative light intensity. 4. The change NAR decreased in early stage of growth, while it increased on August and September, The value of RGR on June under $6{\times}6/m^2$ planting density in 100 light intensity was the highest, and on September under $12{\times}12/m^2$ planting density in 19% relative light intensity was the lowest. 5. Regression and correlation between RGR and NAR showed significantly positive.

• Journal of Environmental Science International
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• v.20 no.11
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• pp.1417-1423
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• 2011

For evaluating the effect of various organic fertilizer ratios on the Spiraea${\times}$bumalda 'Gold Mound' growth, a container green wall system experiment was conducted in a greenhouse at Konkuk university. The experimental planting grounds were prepared with different organic fertilizer ratios ($A_1L_0$, $A_8L_1$, $A_4L_1$ $A_2L_1$ and $A_1L_1$) and with drought tolerance and an ornamental value Spiraea${\times}$bumalda 'Gold Mound' was planted. The change in soil moisture contents, plant height, number of branches, number of dead leafs, number of leaf, number of shoots, length of node, length of leaf, width of leaf, root-collar caliper, chlorophyll contents and survival rate were investigated from April to Jun 2010. 1. The result of soil moisture contents was analyzed with weight unit in the container green wall system during the dry summer season. The soil moisture contents were significantly enhanced in the container green wall system in increasing order as the amount of fertilizer level increased $A_1L_1$ > $A_2L_1$ > $A_4L_1$ > $A_8L_1$ > $A_1L_0$. 2. Compared to the control treatment (amended soil with 100% + organic fertilizer 0%) application, the highest plant growth was observed in the treatment of $A_2L_1$(amended soil with 67% + organic fertilizer 13%) application. However, the differences between the organic fertilizer ratio treatments of $A_1L_1$, $A_4L_1$, $A_8L_1$, and the $A_1L_0$ organic fertilizer application were mostly not significant. 3. The survival rate increased with the increasing application of organic fertilizer, but in the control treatment (amended soil with 100% + organic fertilizer 0%) application all the plants died. Experimental results from the presented study clearly demonstrated that the organic fertilizer improved the survival rate more than the Spiraea${\times}$bumalda 'Gold Mound' growth at different levels of organic fertilizers. This strain can be utilized as a plant growth application in living wall systems during the dry summer season. Therefore, Spiraea${\times}$bumalda 'Gold Mound' is expected to be a highly valuable shrub for the green wall system if it should be considered in integration with stormwater retention or as a soil conditioner for increasing soil water contents in planting ground.

• Journal of Korean Society of Forest Science
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• v.108 no.4
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• pp.610-617
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• 2019

The effects of dippin treatments using Glycyrrhiza uralensis extract (0.5%, 1.0%, 2.0%) and calcium chloride (0.5%, 1.0%, 2.0%) on the quality of peeled chestnuts were investigated. Following dipping treatment, peeled chestnuts were vacuum-packed using a 75-㎛ polyethylene PE and nylon film, and stored in a 0 ℃ incubator for six weeks. The dipping treatments of the peeled chestnuts successfully achieved browning inhibition. The browning degree following 2.0% calcium chloride treatment was the lowest at 0.68 OD. The color change (ΔE) of the peeled chestnuts was the highest (6.0) in the control, and the lowest (3.5) for the 1.0% and 2.0% calcium chloride-treated samples. G. uralensis extract and calcium chloride treatments did not impact weight, moisture loss rate, firmness, or the soluble solid content of the peeled chestnuts following storage. The decay rate was 12.0% in the control group, and 11.0%, 11.5%, and 11.0% for G. uralensis treatment at 0.5%, 1.0%, and 2.0% calcium chloride treatment, respectively, and 13.0%, 9.5%, and 9.0% at 0.5%, 1.0%, and 2.0% calcium chloride treatment, respectively. Sensory evaluation (palatability, off-odor) showed that a 2.0% G. uralensis extract treatment presented excellent results during the storage period. Texture and color indicated no differences as a result of the browning inhibition treatments. Therefore, when considered comprehensively, a 2.0% G. uralensis extract treatment was shown to be effective for maintaining the quality and providing browning inhibition of peeled chestnuts. This result isexpected to solve the problem of quality deterioration in the form of sour taste, which is a problem in chemical processing.

• Food Science and Preservation
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• v.19 no.6
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• pp.799-806
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• 2012

This experiment was conducted to establish the optimum conditions for high $CO_2$ gas treatment in combination with a proper gas-permeable packaging film to maintain the quality of fig fruit (Ficus carica L). Among the fig fruits with different high $CO_2$ treatments, the quality change was most effectively controlled during storage in the 70%-$CO_2$-treated fig fruit. Harvested fig fruit was packaged using microperforated oriented polypropylene (MP) film to maintain the optimum gas concentrations in the headspace of packaging for the modified-atmosphere system. MP film had an oxygen transmission rate of about $10,295cm^3/m^2$/day/atm at $25^{\circ}C$. The weight loss, firmness, soluble-solid content (SSC), acidity (pH), skin color (Hunter L, a, b), and decay ratio of the fig fruits were monitored during storage at 5 and $25^{\circ}C$. The results of this study showed that the OPP film, OPP film + 70% $CO_2$, and MP film+70% $CO_2$ were highly effective in reducing the loss rate, firmness and decay occurrence rate of fig fruits that were packaged with them during storage. In the case of using treatments with packages of OPP film and OPP film+70% $CO_2$, however, adverse effects like package bursting or physiological injury of the fig may occur due to the gas pressure or long exposure to $CO_2$. Therefore, the results indicated that MP film containing 70% $CO_2$ can be used as an effective treatment to extend the freshness of fig fruits for storage at a proper low temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.307-317
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• 2021

In recent years, global warming has led to frequent climate change-related problems, and elevated temperatures, among adverse climatic factors, represent a critical problem negatively affecting crop growth and yield. In this context, the present study examined the physiological traits of wheat plants grown under high temperatures. Specifically, the effects of elevated temperatures on seed development after heading were evaluated, and the vegetation indices of different organs were assessed using hyperspectral analysis. Among physiological traits, leaf greenness and OJIP parameters were higher in the high-temperature treatment than in the control treatment. Similarly, the leaf photosynthetic rate during seed development was higher in the high-temperature treatment than in the control treatment. Moreover, temperature by organ was higher in the high-temperature treatment than in the control treatment; consequently, the leaf transpiration rate and stomatal conductance were higher in the control treatment than in the high-temperature treatment. On all measuring dates, the weight of spikes and seeds corresponding to the sink organs was greater in the high-temperature treatment than in the control treatment. Additionally, the seed growth rate was higher in the high-temperature treatment than in the control treatment 14 days after heading, which may be attributed to the higher redistribution of photosynthates at the early stage of seed development in the former. In hyperspectral analysis, the vegetation indices related to leaf chlorophyll content and nitrogen state were higher in the high-temperature treatment than in the control treatment after heading. Our results suggest that elevated temperatures after the booting stage positively affect wheat growth and yield.

• Korean Journal of Soil Science and Fertilizer
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• v.3 no.1
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• pp.35-41
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• 1970

The experiment was conducted at the salt concentration of 0.5% and 1% end of April, respectively, in low and high-salty and the non-salty areas of silt loam with the Nongkwang, rice variety. The factorial design with confounding blocks of 3 levels each of 10, 15 and 20 kg of N, 8, 12 and 16kg of phosphate and potash, respectively, per 10a was applied. 1. N applications increased by 1.5 and 2 times with the fixed amount of $P_2O_5$ and $K_2O$ (8kg/10a each) increased the proportion absorbed to the applications of N in both non salty and low-salty areas. It was observed that the absorption of Ca and Si was inhibited by either an increased treatment of N alone or combination with the other nutrients in the salty area. 2. In the non-salty area, an increased applications of standard amount of N, $P_2O_5$ and $K_2O$ respectively did not increased the yields. Doubling the application of $K_2O$ resulted in a decreased yield. 3. Applications of additional of 1.5 and 2 times the 10 kg of N per 10a increased the rice yields 12% and 21% respectively, in the low-salty area. An increased application of $P_2O_5$ and $K_2O$ failed to bring about an increased yield. 4. Increasing the application of N gave a significant increased in the yield of rice grain and 1.5 times of N applications were seemed profitable on the high-salty area. Although an increased applications $P_2O_5$ and $K_2O$ seemed to increase the yields of grain, no significant increase was observed. 5. An increased application of N increased the number of panicles up to 1.5 times the standard amount in the non-salty area, but no further increase resulted by doubling the application. The number of panicles was increased in proportion to the increased application of N in both low and high-salty areas. An increased application of $P_2O_5$ increase the number of panicles per unit area in each experimental plot while that of $K_2O$ had no effect but rather decreased the number. 6. The effect of an increased application of N decreased the weight of panicle in the non-salty area, but when the application was increased to 1.5 times or more an increased weight of panicle resulted in both salty areas. Doubling the application had approximately the same effect as 1.5 times the application. Increasing the applications of $P_2O_5$ and $K_2O$ had no effect on the panicle weight in the experimental plots. Increasing the applications of N, $P_2O_5$ and $K_2O$ did not effect the weight of 1,000 grains produced in the non-salty and salty areas. Increasing the application of N decreased the number of grains per panicle in the non-salty area but increased the number of grains per panicle in either salty areas. 7. The ratio of matured grains was highest in the low-salty area and the lowest in the high-salty area. An increased N applications decreased the ratio of matured grains in the non-salty area. No effect was observed in both low and high-salty areas. Increased the $P_2O_5$ and $K_2O$ application showed no effect on the ratio of matured grains in the experimental plots. 8. Increased applications of N, $P_2O_5$ and $K_2O$ was observed not to change the percentage of milling recovery in any experimental plots. Broken rice was increased equally by an increased application of N in the non-salty and salty areas but more remarkably so in the former. 9. Increased applications of N increased the straw production equally in the non-salty, low and high-salty areas. However, no increased production was observed from heavier applications of $P_2O_5$ and $K_2O$. Additional N applications reduced the rate of rough grain weight v.s. straw weight in the non-salty area but increased the ratios in both low and high-salty areas. Additional $P_2O_5$ and $K_2O$ had no effect with the ratio.

• Korean Journal of Microbiology
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• v.41 no.3
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• pp.225-231
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• 2005

The characteristics of cell growth and medium-chain-length polyhydroxyalkanoate (MCL-PHA) biosynthesis of Pseudomonas chlororaphis HS21 were investigated using plant oils as the carbon substrate. The organism was efficiently capable of utilizing plant oils, such as palm oil, corn oil, and sunflower oil, as the sole carbon source for growth and MCL-PHA production. When palm oil (5 g/L) was used as the carbon source, the cell growth and MCL-PHA accumulation of this organism occurred simultaneously, and a high dry cell weight (2.4 g/L) and MCL-PHA ($40.2\;mol{\%}$ of dry cell weight) was achieved after 30 hr of batch-fermentation. The repeating unit in the MCL-PHA produced from palm oil composed of 3-hydroxyhexanoate ($7.0\;mol{\%}$), 3-hydroxyoctanoate ($45.3\;mol{\%}$), 3-hydroxydecanoate ($39.0\;mol{\%}$), 3-hydroxydodecanoate ($6.8\;mol{\%}$), and 3-hydroxytetradecanoate ($1.9\;mol{\%}$), as determined by GC/MS. Even though glucose was a carbon substrate that support cell growth but not PHA production, the conversion rate of palm oil to PHA was significantly increased when glucose was fed as a cosubstrate, suggesting that bioconversion of some functionalized carbon substrates to related polymers in P chlororaphis HS21 could be enhanced by the co-feed of good carbon substrates for cell growth. In addition, the change of compositions of repeating units in MCL-PHAs synthesized from the plant oils was markedly affected by the supplementation of acrylic acid, an inhibitor of fatty acid ${\beta}-oxidation$. The addition of acrylic acid resulted in the increase of longer chain-length repeating units, such as 3-hydroxydodecanoate and 3-hydroxytetradecanoate, in the MCL-PHAs produced. Particularly, MCI-PHAs containing high amounts of unsaturated repeating units could be produced when sunflower oil and corn oil were used as the carbon substrate. These results suggested that the alteration of PHA synthesis pathway by acrylic acid addition can offer the opportunity to design new functional MCL-PHAs and other unusual polyesters that have unique physico-chemical properties.

• Clinical and Experimental Pediatrics
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• v.48 no.8
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• pp.846-856
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• 2005

Purpose : To measure the peak myocardial tissue velocities and patterns of longitudinal motion of atrioventricular(AV) annuli and assess body weight and heart rates-related changes in normal children. Methods : Using pulsed wave Tissue Doppler Imaging(TDI), we measured peak systolic, early and late diastolic myocardial velocities in 72 normal children at six different sites in apical-4 chamber (A4C) view and at four different sites in apical-2 chamber(A2C) view and compared those values with each other, also observing effects with body weights and heart rates. Longitudinal motions of the AV annuli were measured at three different sites in A4C. Results : There were no significant differences of the TDI parameters between gender, ECHO-machines and among the three Doctors performing TDI. Peak myocardial velocities were significantly higher at the base of the heart than in the mid-ventricular region and in the right lateral ventricular wall than in the left lateral ventricular wall or IVS. The TDI parameters showed no significant correlation with fractional shortening(%). Peak systolic and early diastolic myocardial velocities had no correlation with heart rates, but peak late diastolic velocities and A/E ratio correlated positively with heart rates. Correlations between the TDI parameters and body weight were inconsistent. Absolute longitudinal displacement and % displacement were not differ between gender and not correlated with the TDI parameters. Conclusion : We measured the peak myocardial velocities with TDI and the longitudinal motion of the AV annuli using M-mode echocardiography in normal children. With more large scale evaluation, we may establish reference values in normal children and broaden clinical applicabilities in congenital and acquired heart diseases.