• Korean Journal of Organic Agriculture
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• v.22 no.1
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• pp.147-154
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• 2014

Spinach downy mildew caused by Peronospora spinaciae is the main reason of yield reduction in Korea as well as in worldwide. After forced ventilation or horizontal air circulation fans were installed to control growth conditions in green house, the changes of temperature, relative humidity (RH), growth and yield, and occurrence of downy mildew were examined. Althought here was no significant difference of temperature between the treatments, RH as 9.2% lower at nighttime by forced ventilation. In addition, final fresh weight was increased to 17.8g compared to control (10.1g), which as 7.7g enhancement. Downy mildew s tarted to show 20 days after sowing (DAS) and increased to 34.7% at 60 DAS on harvest time in control. In contrast downy mildew was occurred 40 DAS with 0.7% incidence rate and 4% at harvest by forced ventilation. The results indicated that reduction of only 9.2% of RH at nighttime by forced ventilation in greenhouse spinach growth was dramatically thrived over 76.2%. Additionally spinach downy mildew occurred 20 days later with extremely lower incident rate, which meant 88.5% reduction of downy mildew.

• Korean Journal of Agricultural Science
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• v.27 no.2
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• pp.86-94
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• 2000

This study was carried out to determine the effectiveness of uniconazole in ameliorating low and high temperature injury in tomato plants(Lycopersicon esculentum Mill. cvs. Fireball and Patio). Plants were given a soil drench of 0, 0.001, 0.01 or $0.1mg{\cdot}pot^{-1}$ uniconazole, and after 14 days, were treated with 12-h day/12-h night cycles at $25/25^{\circ}C$, $2.5/25^{\circ}C$, $25/2.5^{\circ}C$ or $40/40^{\circ}C$ for 4 days in controlled-environment chamber. Number of damaged leaves per plant, reduction of stem elongation, and overall injury were high at $2.5/25^{\circ}C$, but more reduction of leaf elongation, delay of flowering, and abortion of floral bud were observed in plants at $40/40^{\circ}C$. There was difference in degree of injury between cultivars, thus, 'Fireball' was much affected by unfavorable temperature regimes. All concentrations of uniconazole reduced leaf and stem elongation, increased total chlorophyll concentration, delayed flowering, and significantly provided protection against low and high temperature injury in two cultivars. In general, the application of uniconazole did not inhibit flowering delay and floral bud abortion induced by high and low temperature exposure. Our results support the hypothesis that the role of uniconazole is related to defense system against oxidative stress induced by low temperature stress. Further research is required to clarifu the phytoprotective mechanism of this compound agaist high temperature stress.

• Journal of Life Science
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• v.23 no.2
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• pp.267-272
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• 2013

This study was conducted to eliminate viruses from citrus-infected plants using micrografting and thermotherapy. Six citrus cultivars including a 'Setoka' hybrid were used as plant sources. The TAS-ELISA technique demonstrated that several plants were CTV positive. However, no CTV symptoms were detected in plants obtained from shoots and treated at a high temperature of $40^{\circ}C$ during the day and night and micrografted for two weeks with old trifoliate orange rootstock in vitro. Indexing of CTV, SDV, and CTLV for RT-PCR analysis of the eleven citrus seedlings, including 'Setoka', 'Samdajosang', 'Pungkwang', 'Shiranuhi', and 'Ehimekashi dai28go' was virus free following the micrografting and thermal therapy.

• Journal of Environmental Impact Assessment
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• v.28 no.1
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• pp.23-34
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• 2019

Global warming becomes a serious issue that poses subsidiary issues like a sea level rise or a capricious climate over the world. Because of severe heat-wave of the summer in Korea in 2016, a big attention has been focused on urban heat island since then. Not just about heat-wave itself, many researches have been concentrated on how to adapt in this trendy warming climate and weather in a small scope. A big part of existing studies is mitigating "Urban Heat Island effect" and that is because of huge impervious surface in urban area where highly populated areas do diverse activities. It is a serious problem that this thermal context has a high possibility causing mortality by heat vulnerability. However, there have been many articles of a green infrastructures' cooling impact in summer. This research pays attention to measure cooling effect of a street planting considering urban canyon and type of green infrastructures in neighborhood scale. This quantitative approach was proceeded by ENVI-met simulation with a spatial scope of a commercial block in Seoul, Korea. We found the dense double-row planting is more sensitive to change in temperature than that of the single-row. Among the double-row planting scenarios, shrubs which have narrow space between the plant and the land surface were found to store heat inside during the daytime and prevent emitting heat so as to have a higher temperature at night. The quantifying an amount of vegetated spaces' cooling effect research is expected to contribute to a study of the cost and benefit for the planting scenarios' assessment in the future.

• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.257-263
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• 2006

This experiment was conducted to investigate the optimal media for 'Pechika' ever-bearing strawberry grown in hydroponic culture system in summer highland. Three mixed media (1:1, v/v) of peatmoss with perlite, rice hull, and granular rockwool, and four solution strengths of EC 0.5, 0.75, 1.0 and $1.25 dS{\cdot}m^{-1}$ were tested. Root zone temperature in peatmoss+perlite media was 1 to $3^{\circ}C$ lower than in the other media. The culture medium of mixing to peat moss and perlite was most effective in producing good yield and fruit quality. The culture medium of mixing to peat moss and perlite was the highest about 1,632kg/10a to yield yearly average, but was very undulating 732 kg/10a to yield in 2004 year and 3,013kg/10a in 2003 year. The deformed fruits were increased when the solution strength was increased, especially in EC $1.25dS{\cdot}m^{-1}$. The soluble solids and the acidity content of fruits were increased with higher solution strength regardless of media. The uptake of Ca and Mg was inhibited at higher solution strength, and the uptake of N, P and K was promoted. Therefore, the culture medium of mixing to peat moss and perlite was the most suitable culture medium to product strawberry in summer, because it had the highest yield even though fruit quality among treatments was not significant.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.6
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• pp.21-30
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• 2014

The purpose of this study was to evaluate human thermal comfort in summer by the type of greenery in parks and to explore planning solutions to supply a comfortable thermal environment in parks. The research was conducted in three different land cover types: a park with multi-wide-canopied trees(WOODLAND), park with grass(LAWN) and park with pavement(PAV) as reference sites in Hamyang-Gun SangrimPark. Field measurements of air temperature, relative humidity and wind velocity, short-wave and long-wave radiation from six directions(east, west, north, south, upward and downward) were carried out in the summer of 2014(August 21-23 and 29-30). Mean Radiant Temperature($T_{mrt}$) absorbed by a human-biometeorological reference person was estimated from integral radiation and the calculation of angular factors. The thermal comfort index PET was calculated by Rayman software, UTCI, OUT_SET$^*$ were calculated using the UTCI Calculator and the Thermal Comfort Calculator of Richard DeDear. The results showed that the WOODLAND has the maximum cooling effect during daytime, reduced air temperatures/$T_{mrt}$ by up to $5.9^{\circ}C/35^{\circ}C$ compared to PAV and lowered heat stress values despite increasing relative humidity values and decreasing wind velocity. While the LAWN had very slight cooling effects during daytime, reduced air temperatures/$T_{mrt}$ by up to $0.9^{\circ}C/3^{\circ}C$ compared to PAV, the improvement effects of the thermal comfort index was very slight. However, during nighttime the microclimatic and radiant conditions of WOODLAND, LAWN, and PAV were similar owing to the absence of solar radiation, reduction of wind velocity and an increase in relative humidity. Because the shading and evapotranspiration effects of the WOODLAND were much greater than the evapotranspiration effects of the LAWN, it can be said that the solutions for supplying comfortable thermal environment in parks are to amplify the green volumes rather than green areas. This study was undertaken to evaluate the human thermal comfort in summer of WOODLAND/LAWN parks and to determine the improvement effects of thermal comfort index. These results can contribute to the provision better thermal comfort for park users during park planning.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.148-156
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• 2023

This study was conducted in an indoor cultivation room and chamber where environmental control is possible to investigate the effect of temperature and irrigation interval on photosynthesis, growth and growth analysis of potted seedling cucumber. The light intensity (70 W·m^-2) and humidity (65%) were set to be the same. The experimental treatments were six combinations of three different temperatures, 15/10℃, 25/20℃, and 35/25℃, and two irrigation intervals, 100 mL per day (S) and 200 mL every 2 days (L). The treatments were named 15S, 15L, 25S, 25L, 35S, and 35L. Seedlings at 0.5 cm in height were planted in pots (volume:1 L) filled with sandy loam and treated for 21 days. Photosynthesis, transpiration rate and stomatal conductance at 14 days after treatment were highest in 25S. These were higher in S treatments with a shorter irrigation interval than L treatments. Total amount of irrigation water was supplied evenly at 2 L, but the soil moisture content was highest at 15S and lowest at 25S > 15L > 25L, 35S and 35L in that order. Humidity showed a similar trend at 15/10℃ (61.1%) and 25/20℃ (67.2%), but it was as high at 35/25℃ (80.5%). Cucumber growth (plant height, leaf length, leaf width, chlorophyll content, leaf area, fresh weight and dry weight) on day 21 was the highest in 25S. Growth parameters were higher in S with shorter irrigation intervals. Yellow symptom of leaf was occurred in 89.9% at 35S and 35L, where the temperature was high. Relative growth rate (RGR) and specific leaf weight (SLA) were high at 25/20℃ (25S, 25L), RGR tended to be high in the S treatment, and SLA in the L treatment. Water use efficiency (WUE) was high in the order of 25S, 25L > 15S > 15L, 35S, and 35L. As a result of the above, the growth and WUE were high at the temperature of 25/20℃.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.127-135
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• 1985

The effects of morphological development and environmental temperature on synthesis and accumulation behavior of cell-wall constituents were studied in maize cv. Blizzard and sorghum cv. Sioux and Pioneer 931 at Muenchen Technical University from 1979 to 1981. Various growth stages of maize and sorghum plants were grown on field and phytotron at 4 temperature regimes of 30/25, 25/20, 28/18 and 18/8 degree C and mid-summer sunlight over 13-hour days. The results are summarized as follow: 1. Cell-wall constituents in sorghum and maize plants were shown to have a great synthesis rates at early growth stage from growing point differentiation to final leaf visible. The highest concentration of cell wall contents were found at heading stage with 52-54% and 64-68% of neutral detergence fiber, and 30% and 45% of acid detergence fiber foe maize and sorghum, respectively. 2. The structural carbohydrates, cellulose and hemicellulose, were found as a main components of cell-wall constituents. Cellulose were mainly accumulated in stalks, while hemicellulose were an important cell wall components in leaves and panicle. 3. Synthesis rates of cell-wall constituents and non-strnctural carbohydrates were associated with increasing of temperature. Reserved carbohydrates such as fructosan, mono - and dissaccharose in plant were, however, declined when the temperature exceeded 30 deg C, during the accumulation of cellulose, hemicellulose and lignin were increased continuously. 4. Cell-wall constituents lowered digestibility and net energy accumulation in sorghum and maize plants. In a in vitro and in vivo trial, it was found a negative correlation between digestion dry matter and cell wall constituents, especially cellulose and lignin.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.244-252
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• 2009

This research aims at comparison of climatic conditions of sweet pepper's greenhouse between Korea (KOR) and the Netherlands (NL) to find out the reason of much lower yield in KOR than NL focus-ing on greenhouse climatic conditions. Hence, greenhouse climate data were obtained from each one commercial glasshouse in both countries. The crops (cv. 'Derby') were grown on rockwool slab with two stems per plant with 3.75plants/$m^2$ in KOR and three stems per plant with 2.5plants/$m^2$ or four stems per plant with 1.875plants/$m^2$ in NL. Even though plant density was differed but stem density was on the same to 7.5stems/$m^2$. There was no significantly difference on weekly growth of sweet pepper plant both countries, whereas harvested nodes to whole nodes of NL's plant was more than two times higher compared to KOR. The averaged daily global radiation during the whole growing periods was 14.5MJ/$m^2$/day in KOR and l2.1MJ/$m^2$/day in NL. Averaged 24h temperature was similar to both glasshouse as $21.6^{\circ}C$ in KOR and $21.2^{\circ}C$ in NL during the whole growing periods, however the variance was higher in KOR than NL. Humidity deficit (HD) was observed higher in KOR during the whole growing periods. Averaged day $CO_2$ concentration was measured contrary pattern in both countries because of heating to greenhouse on NL winter season. Averaged 24h temperature and day $CO_2$ concentration to daily global radiation was regular pattern in NL, whereas there are large scatter in KOR. Consequently, more irregular greenhouse climate condition in KOR could be induced irregularly crop growth.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.511-517
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• 2015

This research was conducted to evaluate the influence of root restriction materials and media on the growth of runner plantlets of 'Seolhyang' strawberry in a nursery field. To achieve this, the influence of three kinds of root media on the growth of runner plantlets was monitored when polyethylene film was used as the root restriction material. In addition, the influence of various root restriction materials (RRS) such as transparent polyethylene film (PE), non-woven fabric (NF), perforated polyethylene film (PP), and root proofing sheet (RPS) on the changes in volumetric water content (VWC) and temperature of root media as well as growth of runner plantlet were investigated when expanded rice hull (ERH) was used as the root medium. In the comparison of root media, growth parameters such as leaf area and crown thickness at 20 d after fixation as well as crown thickness and fresh weights of root and above-ground tissue at 40 d after runner plantlet fixation were higher in the ERH treatment than in sandy loam and loamy sand. When the influence of RRS was compared, the VWC of ERH was 55% just after irrigation, but decreased to 26% at just before irrigation. Ranges of the VWC as influenced by irrigation cycle were 16 to 10% in the PP and less than 10% in the NF and RPS. The soil temperature in the PE treatment was around $1^{\circ}C$ lower than in NF, PP, and RPS. The differences between day and night temperatures were also smaller in the PE treatment rather than those in NF, PP, and RPS. The growths of runner plantlet 50 d after fixation showed that plant heights as well as fresh weights of root and above-ground tissue were higher in the PE treatment than in NF, PP, and RPS. NF and PP did not effectively restrict roots inside the medium and the roots of runner plantlets penetrated through the root restriction materials resulting in the formation of root system below the restriction materials. The above results indicate that ERH is more effective than sandy loam or loamy sand as root medium. PE rather than NF, PP, or RPS as root restriction material resulted in better growth of runner plantlets in propagation of 'Seolhyang' strawberry. The results of this research will be used for production of high quality runner plantlets in strawberry propagation.