• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.1
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• pp.59-66
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• 2021

This study aimed to a basic research for the development of dye-sensitized solar cells that the wavelength band required for crop growth is passed, and the wavelength band that is not necessary for crop growth can be used for the generation of electricity. The transmissivity according to the illuminance was about 10% higher in the Blue filter and the Green filter than in the Red filter, but the transmissivity according to the PPFD was about 10% higher in the Red filter and the Blue filter than in the Green filter. In addition, the greenhouse attached with 30% infrared blocking filter was predicted to have a lower air temperature than other greenhouses, but it was investigated that there was no significant difference. Therefore, it was investigated that the application of the infrared cut filter would not be appropriate in a greenhouse that controls the temperature by opening a window. As a result of investigating, it was found that the Green and Blue filter greenhouses had the severe overgrowth and the stems grew weaker. The fresh weight of paprika in the infrared blocking filter greenhouse was the highest at 678.9g, and the growth of Red filter and the control greenhouses was relatively poor. Photosynthetic rate, amount of transpiration, and stomatal conductivity were the infrared blocking filter and control greenhouse higher than others. On the other hand, the water use efficiency did not show a big difference.

• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.288-299
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• 2017

This study was conducted to find out the influence of drought stress on physiological responses of Synurus deltoides. Drought stress was induced by withholding water for 25 days. Leaf water potentials were decreased of both predawn (${\Psi}_{pd}$) and mid-day (${\Psi}_{mid}$) with increasing drought stress, but water saturation dificit (WSD) was 7 times increased. ${\Psi}_{pd}-{\Psi}_{mid}$ showed the significant difference of 0.22~0.18 MPa in stressed before 10 days, and nonsignificant as treatment time became longer. A strong reduction of stomatal conductance ($gH_2O$) and stomatal transpiration rate (E) were observed after 15 days of drought stress Significant reductions of net apparent quantum yield (${\Phi}$) and maximum photosynthesis rate ($Pn_{max}$) were observed after 20 days of drought stress; However, water use efficiency (WUE) was shown the opposite trend. This implies that decrease of photosynthesis rate may be due to an inability to regulate water and $CO_2$ exchanged through the stomata. From JIP analysis, flux ratios (${\Psi}_O$ and ${\Phi}_{EO}$) and performance index on absorption basis ($PI_{ABS}$) were dramatically decreased withholding water after 15 days, which reflects the relative reduction of photosystem II activity. The leaf of S. deltoides showed osmotic adjustment of -0.35 MPa at full turgor and -0.40 MPa at zero turgor, and also cell-wall elastic adjustment of 9.4 MPa, indicating that S. deltoides tolerate drought stress through osmotic adjustment and cell-wall elastic adjustment. The degree of change in water relations parameters such as Vo/DW, Vt/DW decreased with increasing drought stress. This result showed that S. deltoides was exhibited a strong reduction of photosynthetic activity to approximately -0.93 MPa of predawn leaf water potential, and both of osmotic adjustment and cell-wall elastic adjustment in drought stress condition appears to be an important adaptation for restoration in this species.

• Horticultural Science & Technology
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• v.29 no.4
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• pp.317-325
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• 2011

This study was conducted to examine the effect of supplemental lighting on the growth and yield of hydroponically grown sweet pepper (Capsicum annuum L. cv. sprit) under low levels of natural light in winter. The plants were treated with natural light only (control), 3-hour supplemental lighting before sunrise, after sunrise and after sunset with high pressure sodium (HPS, 400W). As the result of these three treatments, the supplemental lighting promoted photosynthesis in the low light intensity condition and particularly photosynthesis was more active right after sun rise in the morning, 1.5-$3.0{\mu}molCO_2{\cdot}m^{-2}{\cdot}s^{-1}$ comparing to those of supplemental lighting after sunset, 0.5-$1.5{\mu}molCO_2{\cdot}m^{-2}{\cdot}s^{-1}$. Transpiration rate and stomatal conductance sharply increased with supplemental lighting after sunrise then they decreased again after turning the lights off. Stomatal size was observed $32.2{\mu}m^2$ after supplemental lighting, whereas the size of the natural light was almost closed at $7.7{\mu}m^2$. The average plant height of sweet papper cv. spirit was 185 cm before sunrise, 188 cm after sunrise and 208 cm after sunset with supplemental lighting for 3hours while the control was 171 cm. With supplemental lighting a better number of fruit set per plant was measured 4.3 before and after sunrise, 3.7 after sunset but 2.6 in the control. Interestingly, there were no significant differences in the sugar content ($^{\circ}Brix$) degree between treatment of supplemental lighting, whereas slight differences between seasons were seen. The marketable fruit yield of sweet pepper (cv. spirit) was $116.0kg{\cdot}ha$ with supplemental lighting, whereas the control (natural light only) was $75.8kg{\cdot}ha$. Despite of spending electricity and depreciation cost, the economic analysis showed net income with supplemental lighting after sunrise was 51% higher than control treatment in cv. spirit.

• Journal of Sericultural and Entomological Science
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• v.15 no.2
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• pp.15-20
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• 1973

This will be second publication regard with silkworm selection using anesthetic followed by previous report. This treatise investigated for nacorsis recovery concerned with silkworm health through more directions than the previous paper. After the author has found a possibility of silkworm seperation through nacorsis recovery, he has recommended to use Balance Health (BH) value system to evaluate or identify silkworm health and to produce better homogeneous silkworm eggs. Also, the author has continued the observation for the next generation how once nacortized parents affect to their family. The obtained results are summarized as followings. 1. Basic investigation a) Hybrid silkworm variety recovers from nacorsis earlyer than pure line because it is stronger. b) Strong pure line variety recovers from nacorsis earlyer than weak one because it is stronger. c) Male worm recovers from nacorsis earlyer than female worm because it is stronger. 2. Establishment of Balance Health(BH) value system. In order to identify each seperated group by nacorsis and their family, the following Balance Health (BH) value indicating system was established.(Table Omitted) 3. In order to select better silkworm during breeding service, the BH value indicating system is strongly recommended. That is, in case BH value is smaller than four, it would be strong group or in case BH value is larger than four, it would be weak group. 4. Once nacortized parents do not harm any nature for next generation regardless P$_1$ or F$_1$ production. 5. The seperation through nacorsis may delay retrograde phenomenon some years than other case, so, this system should be used for pure line production every year. 6. It is recommended to nacortize silkworm for five minutes on breeding purpose, but two and half minutes on pure lines reproduction at fifth instar. 7. This report has been discussed in relation to practical industry promotion aspects, but there are many subjects to be solved from academical aspect in future

• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.172-180
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• 2023

In the current study, four groups; control, 500, 1000, and 2000 mg/L, were treated to investigate the effects of physiological and growth characteristics on Machilus thunbergii under various fertilization levels. As a result of the physiological response to the fertilization treatment, the fertilized group demonstrated relatively higher levels of A, ITE, WUEi, V_camx, PI_abs, and SFI_abs in comparison to the control. The best photosynthetic mechanism was most clearly seen at 1000 mg/L, which involved gas exchange through active stomatal opening and closing. For a productive photosynthetic mechanism. As seen in the growth response of M. thunbergii to fertilization treatment, the fertilized group has significantly higher height, DRC, leaf dry weight, stem dry weight, total dry weight, LWR, and SWR than the control group. A healthy seedling quality index was particularly evident at 1000 mg/L, and other growth indicators were also at a decent level. 500 mg /L also demonstrated growth characteristics that were comparable to those at 1000 mg/L. As a result, M. thunbergii featured the best physiological and growth characteristics in response to the fertilization treatment at 1000 mg/L, and 500 mg/L also showed a similar trend, which is considered to be a good option from an economical perspective.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.349-354
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• 2013

This study examined a technique for cooling root zone aimed at lowering substrate temperature for sweet pepper (Capsicum annum L. 'Orange glory') cultivation in coir substrate hydroponics during hot season, from the $16^{th}$ of July to $15^{th}$ of October in 2012. The root zone cooling technique was applied by using an air duct (${\varnothing}12$ cm, hole size 0.1 mm) to blow cool air between two slabs during night (5p.m. to 3a.m.). Between the $23^{rd}$ of July and $31^{st}$ of August (hot temperature period), average daily substrate temperature was $24.7^{\circ}C$ under the root zone cooling, whereas it was $28.2^{\circ}C$ under condition of no cooling (control). In sunny day (600~700 W $m^{-2}{\cdot}s^{-1}$), average substrate temperatures during the day (6a.m. to 8p.m.) and night (8p.m. to 6a.m.) were lower about $1.7^{\circ}C$ and $3.3^{\circ}C$, respectively, under the cooling treatment, compared to that of control. The degree of temperature reduction in the substrate was averagely $0.5^{\circ}C$ per hour under the cooling treatment during 6p.m. to 8p.m.; however, there was no decrease in the temperature under the control. The temperature difference between the cooling and control treatments was $1.3^{\circ}C$ and $0.6^{\circ}C$ in the upper and lower part of the slab, respectively. During the hot temperature period, about 32.5% reduction in the substrate temperature was observed under the cooling treatment, compared to the control. Photosynthesis, transpiration rate, and leaf water potential of plants grown under the cooling treatment were significantly higher than those under the control. The first flowering date in the cooling was faster about 4 days than in the control. Also, the number of fruits was significantly higher than that in the control. No differences in plant height, stem thickness, number of internode, and leaf width were found between the plants grown under the cooling and control, except for the leaf length with a shorter length under the cooling treatment. However, root zone cooling influenced negligibly on eliminating delay in fruiting caused by excessively higher air temperature (> $28^{\circ}C$), although the substrate temperature was reduced by $3^{\circ}C$ to $5.6^{\circ}C$. These results suggest that the technique of lowering substrate temperature by using air-duct blow needs to be incorporated into the lowering growing temperature system for growth and fruit set of health paprika.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.354-362
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• 2009

This study was performed to develop a suitable nutrient solution for standard rose substrate culture in a closed hydroponic system. 1/4, 1/2, 2/3 and 1 strength of the nutrient solution made by Japan National Institute of Vegetable and Tea Science (JNIVT) were supplied. The photosynthesis rate, quality and growth of cut flower were higher in the 1/2 and 2/3 strength of nutrient solution during high and low temperature period. Based on the above results, optimum nutrient solutions (UOS) were composed by nutrientwater (n/w) absorption ratio with 1/2S ($NO_{3^-}N$ 6.8, $NH_{4^-}N$ 0.7, $PO_{4^-}P$ 2.0, K 3.8, Ca 3.0, Mg 1.2, $SO_{4^-}S$ $1.2me{\cdot}L^{-1}$) at high temperature season and 2/3($NO_{3^-}N$ 9.7, $NH_{4^-}N$ 0.8, $PO_{4^-}P$ 2.2, K 5.0, Ca 3.9, Mg 1.5, $SO_{4^-}S$ $1.5me{\cdot}L^{-1}$) at low temperature season. The results of suitability examination showed that the EC level in newly composed nutrient solution (UOS) was more stable than other nutrient solutions due to its large amount of calcium and potassium. The growth of cut flower cultivated with UOS was higher than those of other nutrient solutions. Especially, the yield of cut flowers in UOS nutrient solution increased 1.4 times than that of other nutrient solution treatments. Consequently, the new nutrient solution investigated in this experiment was suitable for rose cultivation in a closed hydroponic system.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.136-144
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• 1978

A series of experiments over three years was planned for practical application of rhizobia in farms and grass lands in Korea. This is the report for the studies of the first year mainly on the isolation and characterization of rhizobial strains, and on the assessment of their nodulation abilities and nitrogen fixation capacities. 1. Total number of 88 strains for soybean group and 22 st ra ins for pea and vetch group was isolated from nodules which were taken from legumes grown in Daekwanyong, Cheju and various places in Korea. 2. Morphological and cultural characteristics of the strains were studied, and attempts were also made to investigate their antigenic properties and to demonstrate lysogenic strains in these groups. The results were : i) the isolates varied in cultural characteristics on yeast mannitol broth and agar, and in degree of congo reel absorption ; ii) similarities in their antigenic properties were found between/among the strains: G-3/G-9/D216, G-20/G-52 in soybean group; iii) no lysogeny was found in the strains of these groups. 3. Plant infection tests by test tube and bottle method in light room were carried out to elucidate the ability of the strains to nodulate specific legumes and of the capacity of such nodules to fix atmospheric nitrogen. The isolates were grouped into non- invasive, ineffective, or effective to the legumes. Those strains which produced effective nodules, supporting similar level of growth as nitrate control, were: P-3, 4 and 8 in pea and vetch group; G-23, 27, and, D-216 in soybean group.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.162-169
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• 2008

To determine suitable composition of nutrient solution according to soil textures in fertigation culture of cucumber using three strengths (S) of Yamasaki cucumber recipe, chemical changes of soil, growth characteristics and yield of cucumber were investigated. Electric conductivity of drainage solution was risen in all treatments, pH of loam soil was generally optimum level and that of sandy soil was high level. Photosynthetic rate in loam soil supplied the 1/2 S and transpiration rate in sandy soil supplied the 1.0 S were most low. Diffusive resistance in sandy soil supplied the 1.0 S was high. Chlorophyll contents was higher concentrations by the kinds of soil. Amount of drainage solution in sandy loam soil supplied the 1/2 S and loam soil supplied the 1.0 S were most much and little, respectively. Water absorption rate was the opposition to amount of drainage solution. Nutrient contents in soil except calcium were most high in the 1.0 S by the kinds of soil. Nutrient contents in leaves, nitrogen in sandy soil supplied 1.0 S, phosphorus in loam soil supplied 1/2 S, potassium in two soil supplied 1.0 S, calcium in loam supplied 1/2 S and sandy loam soil supplied 1.0 S, magnesium in loam soil supplied the 1/2 S was high. The growth and yield of fruit were more in loam than in sandy loam soil. Therefore, the suitable compositions of macro-nutrients for fertigation culture of cucumber were determined in loam and sandy loam soils as follows: In loam soil, they were $NO_3$-N 12.3, $NH_4$-N 1.0, P 3.0, K 5.9, Ca 5.7, Mg $3.5\;me{\cdot}L^{-1}$, whereas in sandy loam soil $NO_3$-N 11.7, $NH_4$-N 1.0, P 3.0, K 5.9, Ca 4.9, Mg $3.2\;me\;L^{-1}$.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.215-223
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• 1973

A potent citric acid producing strain was selected by an extensive screening test of the yeasts isolated from the various sources. These experiments were conducted to identify the selected strain and investigate the cultural conditions for citric acid production. The results obtained were as fellows: 1. The selected strain of yeast was identified to Hansenula anomala var. anomala by a taxnoomic study of Lodder. 2. The optimum conditions for citric acid production in the basal medium containing 10% glucose were: temperature $30^{\circ}C$, the concentration of $CaCO_3$ 3% and the velocity of oscillation 110 oscills/min. 3. As a nitrogen source ol the basal medium $NH_4Cl(0.1%)$ was the most effective for citric acid production. Organic nitrogen sources such as peptone were adequate for growth of the strain but not for citric acid production. 4. The most effective concentration of glucose was 10% in yield ratio of citric acid from sugar. 5. The addition of defatted rape seed, defatted perilla or defatted rice bran to the medium was effective for citric acid production. When 5% extract solution of defatted rape seed was added, the citric acid production was increased as much as 40% as compared with the case of adding yeast extract(0.2%). 6. The most effective concentration of $KH_2PO_4$ and $MgSO_4{\cdot}7H_2O$ in the medium(for citric acid Production) was 0.05% and 0.025% respectively. 7. Under the optimum cultural conditions, the growth of the strain was continued up to 5 days and the increase of citric acid production was continued up to 6 days, showing the yield ratio of 46% to glucose.