• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.543-547
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• 1995

This study was conducted to light intensity and night interruption on leaf production in perilla. Using two cultivars ; og-dong and Yeup-sil. The present studies were conducted to investigate effect of the light intensity and night interruption for prolongation of vegetative growth by flowering inhibition in the National Honam Crop Experiment Station, R. D. A, Iri, Korea. The results are summarized as followes, varietal differences of days to flower initiation were not significant by the light intensity and night interruption, however differences of days to flower initiation light intensity or night interruption treatment were higly significant. Flowering of perilla was prolongated in high light intensity and in long night interruption. Between the factors treated flowering of perilla was more influenced by light intensity than night interruption. Days to flower initiation of perilla were light intensity(0.5∼1 Lux) in 30 mins night interruption, however 3∼10 light intensity in 60 mins night interruption and 30∼100 Lux light intensity in 10, 30, 60 mins night interruption treatment were not flowering. Plant height, leaf area and dry weight of perilla were the highest in 30∼100 Lux light intensity treatment than in the other treatments. The results would be avaliable establish year-round production methods for low cost of perilla leaf.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.319-324
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• 2022

The objective of this study was to determine the proper night interruption of photoperiods and dark periods for accumulating bioactive compounds of Agastache rugosa without decreasing plant growth. Five-week-old seedlings were transplanted in a DFT system with white LEDs. A. rugosa was treated with night interruption time treatments of 18:1:2:3, 18:2:2:2, 18:3:2:1 (light:dark:light:dark), and 20:4 (control) for 4 weeks. There were no significant differences except for leaf length, leaf width, and the number of flowers. The content of antioxidants in the shoot of A. rugosa was high in tilianin and acacetin, and the content of rosmarinic acid (RA) was significantly higher in the underground part. The RA content per dry weight of A. rugosa was 47.92 and 51.46% higher than that of the control in 18:1:2:3 and 18:2:2:2, and tilianin and acactin per dry weight were significantly higher in 18:3:2:1. There was no significant difference in growth due to the same day light integral, but 18:2:2:2 showed high total polyphenol contents. Therefore, it is thought that the effect of increasing secondary metabolites of A. rugosa without degradation of growth can be expected through night interruption treatment in plant factory cultivation systems using artificial light.

• Horticultural Science & Technology
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• v.30 no.3
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• pp.236-242
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• 2012

We investigated the influences of night interruption (NI) and night temperature on flowering and flower coloration in Cymbidium. Cymbidium 'Red Fire' and 'Yokihi' were grown under a 9 hours photoperiod (control), a 9 hours photoperiod with NI at a low light intensity (LNI) of 3-7 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, or a 9 hours photoperiod with NI at a high light intensity (HNI) of 120 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for four hours (22:00-02:00 HR) for 16 weeks during the reproductive growth stage (Experiment 1). Thirty month-old Cymbidium 'Red Fire' plants with initiated flowering buds were placed in four different growth chamber with night temperature set points of 6, 9, 12, or $15^{\circ}C$ for 16 hours (18:00 to 09:00 HR) and a daytime temperature of $25^{\circ}C$ (Experiment 2). In Experiment 1, the numbers of visible buds and flowers increased, and time to flowering decreased in both the LNI and HNI treatments, as compared to the control in both cultivars. Red color in Cymbidium 'Red Fire' increased by both LNI and HNI, as evidenced by an increased $a^*$ in plants grown under these conditions, relative to those grown under the control condition. Number of days to visible buds at 9-$15^{\circ}C$ ranged from 31-34 days, as compared to 39 days at $6^{\circ}C$ in Experiment 2. Although as the temperature increased days to flowering decreased when the plant was grown at $15^{\circ}C$ as compared to 6, 9, or $12^{\circ}C$, the red color ($a^*$) also decreased. The number of flowers and percent flowering increased when the night temperature was maintained higher than $9^{\circ}C$. Therefore, NI treatment and maintaining the night temperature at approximately 9-$12^{\circ}C$ during the winter season after flower spike initiation in the reproductive developmental growth stage improve flower quality and controls flowering time.

• The Korean Journal of Physiology
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• v.7 no.2
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• pp.17-20
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• 1973

A study was planned to see if the Panax Ginseng has any influence upon the general activity of rats. Seventeen male rats (mean body weight: 204 g) was divided into a ginseng group (N=9) and a saline group (N=8). Once a day for 5 days they received subscutaneously 0. 5m1/100g body weight of ginseng extract solution (4 mg of ginseng alcohol extract in 1 ml of saline), and same amount of saline, respectively. For 20 days beginning from the 1st day of medication on, each rat received activity measurement by means of beam interruption method. Following results were obtained : 1. Activities at night (6 p.m. to 6 a.m. next morning) and in 24hours on the 10 th, 12th, and 13 th day were significantly increased in the ginseng group compared with activities of the saline group. 2. Summed total night and 24-hour activities observed for 15 days after termination of medication were also significantly augmented in the ginseng group compaired with those of the saline group, although no remarkable difference existed between the 2 groups with regard to the summed total daytime activity. It is inferred that the ginseng augments general activity of rats especically at night.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.753-761
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• 2014

Growth and flowering of Cymbidium 'Red Fire' and 'Yokihi' plants were examined in a greenhouse with cooling systems in summer, and with night interruption (NI) lighting in winter as a forcing culture system. The greenhouse was divided into two sections with separate cooling controls during the summer season. One section was cooled by a mist system (mist), while the other section was cooled by a shade screen (shade). During the winter, the greenhouse was redivided into three sections within each cooling system. Plants were grown with NI either at a low light intensity of $3-7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(LNI) or a high l ight intensity of $120{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(HNI) u sing h igh-pressure sodium l amps during the 22:00-02:00 HR. The control plants were grown under 9 h short-day condition. NI for 16 weeks and cooling for 9 weeks were employed twice during the 2 years of the experimental period. The air temperature was approximately $2^{\circ}C$ lower in the mist than in the shade and the relative humidity was 80 ${\pm}5%$ in the mist compared to $55{\pm}5%$ in the shade. The daily light integral in the mist section was 48% higher than in the shade section. The time from initial planting to flowering pseudobulb emergence decreased with both LNI and HNI for both cultivars, regardless of the cooling treatments. Under NI conditions, however, between 60% and 1 00% of plants of both cultivars flowered in the mist, whereas no or 20% of 'Red Fire' or 'Yokihi' plants, respectively, flowered in the shade treatment over 2 years. Plants grown under the mist had bigger pseudobulbs than those grown in the shade under both NI treatments. These results show that commercial use of NI in winter and a mist cooling system in summer would decrease crop production time to 2 years and increase profits in Cymbidium forcing culture.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.434-439
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• 2014

This research was conducted to examine the effects of night interruption (NI) at different times on vegetative growth and flowering in Salvia splendens 'Salsa'. Plants were grown in a growth chamber under 9-h photoperiod (short-day, SD) or 9-h photoperiod plus NI with light intensity at $3-5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux. The NI was applied at 18:00-22:00 HR (NI18), 22:00-02:00 HR (NI22), or 02:00-06:00 HR (NI02). The net photosynthetic rate under NI18, NI22, and NI02 increased by 0.33, 0.16, and $0.13{\mu}mol{\cdot}CO_2{\cdot}m^{-2}{\cdot}s^{-1}$, respectively, during the NI period. Dry weight, plant height, and the number of nodes under NI were not significantly different from those of the plants under SD. However, flowering was earlier by approximately 9.8 days, and the number of flowers increased to 138.7 in NI02 compared to 36.4 flowers under SD at 17 weeks after the treatment. Our results indicate that NI02 was the most effective treatment in promoting flowering. Although vegetative growth of salvia was not increased in response to the increased net photosynthesis, flowering was promoted. Under NI18, NI22, and NI02 treatments, 77.8, 88.9, and 100.0% of salvia plants flowered within 8 weeks, whereas 44.4% of the plants flowered within the same time under SD conditions.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.24 no.1
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• pp.29-45
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• 1996

Before (March 26, 1994) or after the occurrence of a downslope windstorm (March 29), the NO, $NO_2$, and $SO_2$ at the ground level of Kangnung city were monitored with high concentrations in the afternoon, due to a large amount of gases emitted from combustion of motor vehicle and heating apparatus, especially near 1600-1800 LST and 2000-2100 LST, but at night, they had low concentrations, resulting from small consumptions of vehicle and heating fuels. When both moderate westerly synoptic-scale winds flow over Mt. Taegwallyang and easterly meso-scale sea breeze during the day, atmospheric pollutants should be trapped by two different wind systems, resulting in higher concentration at Kangnung city in the afternoon. At night, the association of westerly synoptic wind and land breeze can produce relatively strong winds and the dissipation by the winds cause these low concentrations to lower and lower, as nightime goes on. From March 27 through 28, an enforced localized windstorm could be produced along the lee side of the mountain near Kangnung, generating westerly internal gravity waves with hydraulic jump motions. Sea breeze toward inland appartantly confines to the bottom of the eastern side of the mountain, due to the interruption of eastward violent internal gravity waves. As the windstorm moves down toward the ground, an encountering point of two opposite winds approaches Kangnung, and a great amount of NO and $NO_2$ were removed by the strong surface winds. Thus, their maximum concentrations are found to be near 18 and 20 LST, 17 and 21 LST. In the nighttime, the more developed storm should produce very strong surface winds and the NO and $NO_2$ could be easily dissipated into other place. The $SO_2$ concentration had no maximum value, that is, almost constant one all day long, due to its removal by the strong surface winds. Especially, the CO concentrations were slightly lower during the strom period than both before or after the strom, but they were nearly constant without much changes during the during the daytime and nighttime.

• Journal of the korean society of oceanography
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• v.33 no.1-2
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• pp.35-40
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• 1998

In February and April 1997, three temporary interruptions of electric power production at the Uljin Nuclear Power Plant in the east coast of Korea were caused by the malfunction of the cool-ing-water supply unit. The clogging of the drum screens inside the unit caused by the surface swarm of the euphausiid Euphausia pacifica Hansen might be responsible for the malfunction. These incidents were of particular interest since such interruption of reactors' operation by krill swarms had not previously been reported. Using samples caught by the drum screens inside the cooling water-supply unit, we investigated the population structure of surface swarms. One occasion of nighttime and three occasions of daytime surface swarms were found in February and April 1997, respectively. The foreguts of more than 60% of E. pacifica in nighttime surface swarm were in full condition. This evidence suggests that E. pacifica aggregates to the surface water at night for feeding. In daytime surface swarms consisting of mature E. pacifica, however, foreguts in full condition were only found in less than 10eio of krill examined, suggesting that daytime surface swarms are closely related to breeding activity. During the study period, the growth rate of mature females was more than twice higher than that of mature males. Analyses of the sex-ratio and length-frequency data show a decrease in the portion of males with increasing size. There was a decline in the number of males of 19 mm in length. Energy loss during spermatophore transfer may result in the death of male E. pacifica, as found in male E. superba.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.207-219
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• 2016

Incandescent (INC) lamps have been commonly used to promote flowering of long-day (LD) plants during short-day (SD) seasons, but production of INC lamps has been prohibited due to their low energy efficiency. One of the light sources replacing INC lamps is a compact fluorescent lamp (CFL). This study was carried out to compare the flowering and morphological responses of LD annuals grown in a controlled environment greenhouse at $20^{\circ}C$ with a truncated 9-h SD and a 2- or 4-h night interruption (NI) or 6-h day extension (DE) provided by lighting from INC lamps, CFLs, or a combination of the two (INC + CFLs), in which red (R) to far-red (FR) ratios were 0.60, 8.46, and 0.91, respectively, and their PPFDs were $2.3{\pm}0.3{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. After 12 weeks of treatment, $Petunia{\times}hybrida$ 'Wave Purple' plants did not flower under the SD photoperiod whereas 100% flowered under all of the LD treatments. Flowering was more rapid under the INC or INC + CFL lighting treatments compared to CFL and DE, and 4-h NI enhanced flowering compared to 2-h NI. In addition, plants under DE and 4h-NI generally flowered earlier than under 2-h NI. All petunia 'Single Dreams Red' plants flowered within 65 days after treatment, and flowering was hastened by some LD lighting regimens and lamp types. Plants under DE and 4h-NI generally flowered earlier than under 2-h NI INC or INC + CFL compared to FL, and flowering time under INC 6-h DE was earliest. In addition, INC lighting promoted stem elongation of both petunia cultivars. In both pansy (Viola${\times}wittrockiana$) 'Coiossus Yellow' and 'Delta Blue Blotch', LD treatments, especially using INC lamps, promoted flowering whereas the lighting period had little influence on days to flowering. Therefore, INC or INC + CFL with lower R:FR promoted flowering and stem extension and the promoting effect was larger with longer lighting periods. These results suggest that CFLs can be used to provide LDs to promote the flowering of petunia and pansy and to reduce stem elongation, although the promoting effect on flowering is sometimes less than that of INC lamps alone.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.341-348
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• 2013

We desinged and evaluated a remote-sensing sex pheromone trap for real-time monitoring of Mythimna separata (Lepidoptera: Noctuidae), a migratory insect in Korea. The system consisted of a modified cone-trap with a sex pheromone lure, a sensing module based on light interruption, a signal transmission module based on code division multiple access, a main electronic board for system control, a power supply based on a solar collector, a stainless steel-pole supporting the system, and a signal collection and display system based on an internet web page. The ratio (>92%) of the actual number of insects to the signal number in the remote-sensing trap was improved by sensing only within a limited period at night on the basis of the insect's circadian rhythm, control of signal sensitivity on the basis of sensing software programming, 1-h interval for signal transmission, and adjustment of the signal transmission program. The signal occurrence pattern in the remote-sensing trap was conclusively similar (correlation coefficient, >0.98) to the actual pattern of adult occurrence in the trap. The result indicated that the remote-sensing trap based on the attraction of the sex pheromone lure for M. separata has a promising potential for practical use. Occurrence of M. separata adults was observed several times in 2011 and 2012, and the peaks were sharp.