• Korean journal of applied entomology
• /
• v.55 no.1
• /
• pp.35-43
• /
• 2016

The temperature-dependent development of Metcalfa pruinosa overwintering eggs was investigated at ten constant temperatures (12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, and $35{\pm}1^{\circ}C$, Relative Humidity 20~30%). All individuals collected before April 13, 2012 failed to develop into first instar larvae. In contrast, some individuals that were collected on April 11, 2013 successfully developed when reared under $20{\sim}32.5^{\circ}C$ temperature regimes. The developmental duration was shortest at $30^{\circ}C$ (13.3 days) and longest at $15^{\circ}C$ (49.6 days) in the fourth collected colony (April 26 2013). Developmental duration decreased with increasing temperature up to $30^{\circ}C$ and development was retarded at high-temperature regimes ($32.5^{\circ}C$). The lower developmental threshold was $10.1^{\circ}C$ and the thermal constant required to complete egg overwintering was 252DD. The Lactin 2 model provided the best statistical description of the relationship between temperature and the developmental rate of M. pruinosa overwintering eggs ($r^2=0.99$). The distribution of the developmental completion of overwintering eggs was well described by the 2-parameter Weibull function ($r^2=0.92$) based on the standardized development duration. However, the estimated cumulative 50% spring emergence dates of overwintering eggs were best predicted by poikilotherm rate model combined with the 2-parameter Weibull model (average difference of 1.7days between observed and estimated dates).

• Korean Journal of Plant Resources
• /
• v.19 no.2
• /
• pp.218-222
• /
• 2006

This experiment was conducted to investigate the effects of climatic factors varied due to the type of plastic house, cultural season and location in the house on the growth of cucumber plants grown by nutrient solution. There were two growing periods, summer culture and retarding culture, two types of plastic houses, 1-2W type house and post-less house. Air temperature, relative humidity and amount of solar radiation in the plastic houses were measured. Also, dry weight of leaves and stems, plant height, number of leaves per plant, leaf area per plant and fresh weight of fruits per plant were observed. Plant growth analysis were conducted and interrelationships between climatic factors and physiological characteristics were investigated. The results were as follows. There were no differences between the type of plastic houses in the average air temperature and average relative humidity in the plastic house, but amount of solar radiation in 1-2W type house was significantly higher than that of postless house. Daily cumulative solar radiation were highest in southwest side of 1-2W type house and northwest side of postless house. Plant height and number of leaves per plant were higher in summer culture than retarding culture, while leaf area per plant was higher in retarding culture than summer culture. Relative growth rate (RGR) showed highly significantly positive correlations with net assimilation rate (WAR) and leaf area ratio (LAR). Contribution of NAR to RGR was much higher than that of LAR. Crop growth rate (CGR) showed highly significantly positive correlations with leaf area index (LAI). It appeared that increase of LAI was important to increase productivity of cucumber. Average daily air temperature for the whole growing period showed highly significantly positive correlations with RGR and NAR. Furthermore, cumulative solar radiation for the whole growing period in retarded culture showed significantly positive correlation with RGR and NAR.

• Journal of Plant Biology
• /
• v.12 no.3
• /
• pp.26-34
• /
• 1969

Through immersing barley seeds (variety; Suwon No. 6) into different dilution of carrier-free P-32 original solution (Total activity; 90mc, To; 3/21) for 24 hours at room temperature, four groups of seeds (each group consists of 200 seeds) having activity levels of 1.6$\times$10-3$\mu$c 32P/grain, 2.3$\times$10-1$\mu$c 32P/grain 6.9$\times$100$\mu$c 32P/grain and 2.5$\times$101$\mu$c 32P/grain respectively, were obtained. To investigate the effects of various activity levels of P-32 absorbed upon the test plants, the seeds were germinated, transplant into the pots, and the growth was observed for three months after germination. After harvest, the inorganic contents in the leaves and the stems were also analyzed. The results: 1) Until four days after the beginning of germination, the rate of germination was found the lowest at the strongest activity level of 2.5$\times$101$\mu$c/grain. At the other P-32 levels treated, it showed generally higher than the control. 2) Before transplanting the seedlings of both 1.6$\times$103$\mu$c/grain and 2.3$\times$10-1uc/grain levels showed more vigorous growth than the control, whereas at the 6.9$\times$100 uc/grain level a retarded growth was conspicuous and all of plants belonging to the highest activity level of 2.5$\times$101$\mu$c/grain were withered owing apparently to the radiation damage. 3) This trend of growth promotion was continnually observed at the low activity levels even after transplanting the seeldings to the pots. As for the plants belonging to 6.9$\times$100$\mu$c/grain level, a clear sign of gradual recovery from the damage afflicted at the earlier stage was observable, and as a result the plants showed more growth than those of control two months after transplanting. 4) The number of stems diverged was found somewhat small in the blocks treated with P-32, compared with that of control until two months after germination. At the later stage of growth there seemed no significant difference among the themselves. 5) The dry weight of leaves and stems was proved that the lower the activity, the mroe it was produced. The relative increase of dry matter in each treatment compared with the control was 2% at 6.9$\times$105$\mu$c/grain level, 9% at 2.3$\times$10-1$\mu$c/grain and 35% at 1.6$\times$10-3$\mu$c/grain respectively. 6) The inorganic contents of the leaves and stems harvested were proved that: (1) Nitrogen was highest at the lowest activity level of 2.3$\times$10-1$\mu$c/grian. (2) Phosphorus showed generally higher contents in the treated blocks than in control, with the peak being at 2.3$\times$10-1$\mu$c/grain. (2) Phosphorus showed generally higher contents in the treated blocks than in contro, with the peak being at 2.3$\times$10-1$\mu$c/grain level in the leaves and at 6.9$\times$100$\mu$c/grain in the stems. (3) These was no significant difference in potassium contents in the leaves between treatment and control, whereas in the stem the treated blocks were higher than control roughly in propotion to the activity level. (4) Calcium in the lesves was richer in treated blocks than control while in the stem no difference was seen. (5) Magnesium contents both in leaves and in stems there was no difference among treatments.

• Horticultural Science & Technology
• /
• v.30 no.5
• /
• pp.477-483
• /
• 2012

This study was carried out to investigate the influence of copper concentrations in fertilizer solution on the growth of and nutrient uptake by domestically bred strawberries. The characterization of toxicity symptoms as well as tissue analyses based on dry weight of above ground tissue were also conducted to determine the threshold levels in plants when toxicity developed in copper. The dry weights of the above ground tissue were not significantly different among the treatments of 0.25 mM to 1.0 mM in 'Keumhyang' and 'Maehyang' strawberries and that of 0.25 mM to 3.0 mM in 'Seolhyang' strawberry. This indicates that the 'Seolhyang' strawberry is more tolerant to copper toxicity than 'Keumhyang' or 'Maehyang' strawberries. Application of copper at high concentrations resulted in severe toxicity such as death of extensive areas of leaves. The lower leaves became yellow and die rapidly as the symptoms spread up the plants. The leaf blades and petioles died back to the crown and hang on by mechanical attachment. Symptoms of copper toxicity in lower leaves developed as browning on leaf margins and in patches between leaf veins that became necrotic. The elevation of copper concentrations in fertilizer solution did not influence the tissue phosphorus, potassium, calcium, and magnesium contents based on the dry weight of the above ground tissue. The tissue copper contents increased lineally as the copper concentrations in fertilizer solution were elevated. But the tissue iron, manganese and boron contents were not influenced by the concentrations. When the concentration of copper at which growth of a plant is retarded by 10% is regarded as threshold level, the copper contents based on dry weight of above ground plant tissue should be lower than 71.4, 57.9 and 74.8 $mg{\cdot}kg^{-1}$ in 'Keumhyang', 'Maehyang' and 'Seolhyang' strawberries, respectively. The symptom characterization and established threshold level in copper toxicity would help growers to prevent the reduction of crop growth and yield in 'Seolhyang' strawberry cultivation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.4 no.2
• /
• pp.167-175
• /
• 1971

A pot experiment with an acid sulfate soil from Kimhae was carried out to find out the cause of toxicity in rice plant. The effect of liming on changes in pH, Eh, Al, and $Fe^{2+}$ in soil and leachate was examined at two-week interval during the growth of rice. Also, total $P_2O_5$, $SiO_2$, Fe and Al contents in plants at harvesting stage were determined. In the early stage, the rice plant in the check soil showed the same healthy growth as did in limed soil even at high Al in soil and leachate. Around panicle forming stage, reddish brown mottlings suddenly infested all over the plants when accompanied with strong reduction, and afterward growth was severely retarded, and finally caused the significant difference in yield. During the strong reduction, significant amount of sulfide was formed only in check soils, but no free $H_2S$ was detected. Appreciable Al was still present in soil and leachate, and $Fe^{2+}$ in check soil was lower than that in limed soil, but $Fe^{2+}$ in leachate was slightly higher. Limed soils were more reduced and produced more $Fe^{2+}$ due to increased microorganism activity in the neutral pH. In the leachate, the check showed slightly higher $Fe^{2+}$ concentration but considerably higher than limed one at later stage. Appreciable amount of Al was detected only in check soil and leachate from transplanting to panicle formation stage. Plant tissues at harvesting stage contained very low P regardless of liming. Uptake of Si was markedly increased by liming. Contents of Fe an Al was markedly higher in check than limed one, but difference in Fe content was more drastic possibly due to more Fe uptake in presence of markedly higher $Fe^{2+}$ in soil and leachate at later growing stage. In conclusion toxic symptom in this acid sulfate soil seems to be primarily due to Al when accompanied with low pH and strong reduction. But association with $Fe^{2+}$ toxicity is not completely excluded. In order to differentiate the effect of $Fe^{2+}$ from that of Al more detailed plant analysis at different stage is required.

• Korean Journal of Soil Science and Fertilizer
• /
• v.33 no.4
• /
• pp.292-301
• /
• 2000

To make a better use of the beneficial bacterial inoculants in the agricultural practice, dry forms of bacterial fertilizer or pesticides are prepared with carrier materials. During the drying process of bacterial inoculant, most of the cells face a severe osmotic pressure and dehydration, and die off. Our study describes the effect of osmoprotectants such as trigonelline and trehalose on the survival of bacterial cells in high salt concentration and drying conditions. A fluorescent Pseudomonas, strain SSL3, used in this study, could grow in high salt concentration of upto 5% but the cells could not overcome the growth retardation at over 7% of salt concentration. The addition of trigonelline, even on small amount, in liquid medium containing 4% NaCl was detrimental to the cell. However, the addition of trehalose of upto 10 mM to the liquid medium containing 4% NaCl, enhanced cell growth. The cell growth was retarded when 150mM trehalose was added to the medium. Upon dry formulation of cells, trehalose was added. And the dry cells were inoculated into the soil to determine the effect of osmoprotectants on the survival of the cells. The survival of the cells, both in wet or dry soil, was improved by the addition of trehalose during the dry cell formulation. The positive effect of trehalose on the cell survival at $-20^{\circ}C$ and $-70^{\circ}C$ was oven more pronounced. The FTIR (Fourier transformation infra-red) spectroscopic analysis showed that the change of the 2nd amide group was reduced by adding trehalose to the medium containing 4% NaCl. These results suggest that trehalose can protect the cell membrane from dryness or high concentration of salt, thereby diminishing the sudden change of the protein structure of the cell membrane and, as a consequence, improving the cell survival.

• Korean journal of food and cookery science
• /
• v.11 no.3
• /
• pp.309-315
• /
• 1995

This study was conducted to examine the effects of fish sauces from shrimp and anchovy and chitosan on the changes in pH, acidity, texture, and pectin fraction during Kimchi fermentation. Also, we conducted sensory evaluation on the textural properties of various Kimchis. The results were as follows: During fermentation, pH was decreased in the order of fermented anchovy sauce, fermented shrimp and control. And acidify was increased in the same order. But the addition of chitosan retarded the decrease in pH and increase in acidity. The compression force of various Kimchis during fermentation was decreased in the rder of fermented anchovy sauce, fermented shrimp, control and the addition of chitosan. During fermentation, hot water soluble pectin (HWSP) of control, fermented shrimp and fermented anchovy sauce increased whereas HCI soluble pectin (HCISP) in there treatments decreased. On the while, HWSP decreased and HCISP increased by addition of chitosan. Sensory score for the texture parameters such as hardness, crispness and chewiness of various Kimchis after the 3rd and 5th days of fermentation showed that hardness, crispness and chewiness were higher in chitosan treatment than in other treatments. The pH and acidity, compression force of Kimchis were appeared to be most highly correlated with crispness, showing that pH and compression force gave positive correlation and acidity gave negative correlation with crispness respectively. From the above results, chitosan addition was observed to infuluence the textural properties of Kimchi and their pectic substance.

• Korean Journal of Social Welfare
• /
• v.57 no.2
• /
• pp.5-40
• /
• 2005

Social welfare centers and residential care facilities where provide the socially disadvantaged with proper social services, face financial difficulties. This is because not only of the lack of governmental support, but also of social welfare centers and residential care facilities' lack of skills in developing abundant resources from the private sector. In this context, this study tried to find factors affecting resource mobilization of the social welfare facilities to devise policies in resource development. Mail survey was conducted with the structured questionnaire. Employees in charge of community resource development were asked to answer the questionnaire. The study population were welfare centers and residential care facilities. A total of 293 community welfare centers and 632 residential care facilities responded to the survey. The response rate was about 62%. The dependent variables of the study were the amount of resource mobilization in the year 2001 which was measured as the number of donors, the total amount of donation, and estimated amount of gift-in-kind. Three types models were constructed per each welfare institution. Independent variables were selected based on the previous research findings: community environment factor, structural factor, and resource development factor. Multiple regression was utilized to analyze the data. The resource development factor turned out to be significant variable in various models. In the models of donors, the amount of donation, and the amount of gift-in-kind (except for the welfare center model), at least one out of six variables of the resource development factors was significant welfare center. Welfare centers which establish the resource development department or hire employees to take care of resource development, utilize computer softwares to file donors, and utilize donor management programs, have more donors and/or donations than their counterparts. In addition, residential care facilities located in urban area have more donors and donations, and among residential facilities those for the disables, those with longer history and more employees, receive more donations than their counterparts. As for the gift-in-kind model, the welfare centers located in high income area and residential care facilities for the elderly, children and mentally retarded receive less gift-in-kind than their counterparts Based on the above findings, this study suggested that to mobilize resources the welfare centers as well residential care facilities need to have community resource development department or resource development staffs, adopt computer software to systematically organize donors, and utilize donor mobilizing and maintaining programs.

• Journal of Bio-Environment Control
• /
• v.26 no.3
• /
• pp.151-157
• /
• 2017

The objectives of this study were to determine the impact of soil water content on the growth, stomatal conductance, and photosynthesis of Kimchi cabbage and to evaluate proper parameters for development of growth models. There were five levels of irrigation amount treatments (0, 200, 300, 400, and 500 mL/d/plant) and those were commenced at one day after transplanting (DAT). We measured soil water content, stomatal conductance, photosynthesis characteristics, and the A-Ci curve. The growth of Kimchi cabbage as affected by irrigation amount was evaluated at 38 days after transplanting, however, the growth with 0 and 200 mL/d/plant irrigation amount treatments measured at 29 DAT. The relationship between soil water content and stomatal conductance was highly correlated ($r^2=0.999$) and the function represented by y = 6097.4x - 4.2984. The stomatal conductance of Kimchi cabbage leaves showed $300mmol{\cdot}m^{-2}{\cdot}s^{-1}$ when the soil water content was below $0.05m^3/m^3$. The stomatal conductance was rapidly decreased by scarcity of soil moisture. A-Ci curve indicated normal curve in fully irrigation treatment (500 mL/d/plant), however, $CO_2$ couldn't diffuse through the intercellular Kimchi cabbage leaves treated with 0 mL/d/plant. The dry weight of full irrigation treatment was greater approximately 6.8 times than that of deficit irrigation (0 mL/d/plant). In addition, leaf area index showed a logarithmic function (y = 16.573 + 3.398 ln x) with soil water content and that of R-squared represents 0.913. Results indicated that the soil water content was highly correlated with stomatal conductance and leaf area index. Indeed, the scarcity soil moisture reduced photosynthesis and retarded growth.

• Journal of Bio-Environment Control
• /
• v.29 no.4
• /
• pp.388-398
• /
• 2020

Watermelon yield mainly depends on soil water content controlled by irrigation in a plastic greenhouse. In this study, we investigated the effect of different soil moisture contents affected by irrigation starting point on growth, yield, and physiological responses of small-sized watermelons. Irrigation was initiated at 5 different levels of soil water content as a starting point with soil moisture detecting sensor after 14 days of transplanting, and stopped at 7 ~ 10 days before harvest. These treatments were compared with the conventional periodic irrigation as control. When soil had the lowest moisture content (-50 kPa), the overall shoot growth was retarded, but the root length and root dry weight increased. The photosynthetic parameters (photosynthetic rate, stomatal conductance, and transpiration rate) of watermelon leaves decreased significantly in the lowest soil moisture content (-50 kPa). On the other hand, the photosynthetic rates of watermelon leaves grown with irrigation starting point between -20 and -40 kPa were observed to be higher than those of other treatments. Fruit set rate and marketable fruit yield increased significantly at -30 kPa and -40 kPa. Proline, abscisic acid (ABA), total phenol and citrulline, which are known to contribute to stress tolerance under drought condition, increased as soil water content decreased, particularly, the largest increases were recorded at -50 kPa. From these results, it was found that an appropriate water supply adjusted with an irrigation starting point between -30 and -40 kPa could help to keep favorable soil water content during the cultivation of small-sized watermelons, promoting the marketable fruit production as well as inducing the vigorous plant growth and reproductive development.