• Journal of Ginseng Research
• /
• v.34 no.4
• /
• pp.274-281
• /
• 2010

This experiment was conducted to examine ginseng lines resistant and susceptible to high-temperature injury and to investigate characteristics of the selected lines: leaf burning phenomenon, chlorophyll content, quantum yield, and maximum light interception rate. The leaf burning phenomenon incidence rates of the resistant lines Yunpoong, high-temperature injury resistance (HTIR)1, HTIR2, and HTIR3 were low: 5.8%, 3.6%, 4.0%, and 1.9%, respectively. Resistance of the susceptible lines Chunpoong, high-temperature injury susceptible (HTIS)1, and HTIS2 was high: 58.5%, 23.2%, and 21.7%, respectively. The chlorophyll content (SPAD value) of the resistant lines Yunpoong, HTIR1, HTIR2, and HTIR3, which were exposed to high temperatures and intense light, remained as high at 24.8, 27.9, 24.9, and 30.6, respectively, but that of the susceptible lines Chunpoong, HTIS1, and HTIS2 was low at 21.0, 21.1, and 20.1, respectively. During the summer season, the quantum yield of the resistant lines (Yunpoong, HTIR1, HTIR2, and HTIR3) changed little, but that of the susceptible lines (Chunpoong, HTIS1, and HTIS2) changed dramatically. The maximum light interception rate (Fm/Fv value) for the resistant lines (Yunpoong, HTIR1, HTIR2, and HTIR3) was as high as 0.848, 0.794, 0.805, and 0.813, respectively, while that of the susceptible lines (Chunpoong, HTIS1, and HTIS2) was 0.678, 0.642, and 0.717, respectively. Based on these results, the high-temperature injury-resistant lines seemed to be less susceptible to high light, even at high temperatures. Future studies on red ginseng quality and its active ingredients in resistant ginseng lines and field experimentation will be conducted to verify the potential of the resistant lines.

• 전기의세계
• /
• v.22 no.1
• /
• pp.35-41
• /
• 1973

An automatic point traffic control method is recommended for more idealistic traffic flow over coarse road netowrks. The automatic control apparatus recommended, consists of a transceiver, amplifier, digital-to-analog converter, signal light controller for emergency and steady state, and digital counter as monitor. The transmitter sends a signal to the target vy means of Microwave-FM-CW and a diode detector picks up the echo signal. Thus the operation of the entire system will be carried out through an open loop state. Some factors necessary for an ideal detector system are rapid response, longevity and stability. An analytical method of the Doppler effect substitutes the conventional frequency deviation into the amplitude of detector output. The changing rate of amplitude is proportional to the voltage of the detector output. Some induced formula from Maxwell's radiation field theory ensures this new method, and, new method, and proves the fact with an experimental data presentation. Stability depends upon Klystron as an oscillator and a diode as a detector. the transceiver installation affects on the response and sensitivity of the system. In accordance with the detector output, several targets are easily classified by amplitudes on the scope. The traffic flow, i.e., target movement which is analyzed by the amplitude method, is shown through the scope and indicates it on the digital counter. The best efficiency for the amplitude analysis can be attained through use of an antenna having the highest sensitivity.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.7
• /
• pp.1187-1194
• /
• 2008

This paper presents a high-power electronic ballast for a metal-hallide lamp(MHL) that employs frequency modulation(FM) technique to eliminate acoustic resonance(AR). The proposed ballast consists of a full-bridge rectifier, a power factor correction(PFC) circuit, a full-bridge(FB) inverter, an ignitor using LC resonance and an FM control circuit. Whereas a manual PFC provides advantages in terms of high reliability and low cost for constructing the circuit, it is difficult to supply a stable voltage because of the output voltage ripple that occurs with a period of 120Hz. Although the ballast can be designed with a small size and a light weight if it is driven at a switching frequency between 1 and 100 kHz, AR will occur if the eigen-value frequency of the lamp coincides with the inverter's operation frequency. The operation frequency was modulated in real time according to the output voltage ripple to compensate for the variation in power supplied to the lamp and eliminate AR. Performance of the proposed technique was validated through numerical analysis, computer simulation using PSPICE and by applying it to an electronic ballast for a prototype 1kW MHL.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.23 no.5
• /
• pp.1372-1383
• /
• 1998

In this paper, modeling for DC and AC characteristics analysis of DFB-LD was performed considering effects of .lambda./4-shifted gratingandspatial hole burning within a laser diode cavity. From the simulation for DC characteristics, Light-Current curve, optical power distribution and carrier density distribution within the cavity can be obtained. The simulation for AC characteristics porovides IM response and the amplitude and phase and the amplitude and phase response of FM with excellent accuracy.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.4
• /
• pp.296-302
• /
• 2001

Winter cereals are acclimated during wintering, and thereafter their freezing resistance is increased. In order to analyze inheritance and heritabilities for photoinhibition of photosynthesis by high light intensity under low temperature, and to evaluate the relationship between low temperature-induced photoinhibition and winter survival, 4 parental half diallel crosses were used. The detached leaves of 7-8cm long from plants grown for 35 and 55 days were placed on wet filter paper and placed in trays at 5$^{\circ}C$ cold room with 1,200 $\mu$mol $m^{-2}$ $s^{-1}$ PPFD. Chlorophyll fluorescence was measured with a chlorophyll fluorescence system after dark adaptation for 30 min. The Fv/Fm of 35day old plants was reduced from 0.714 in the control leaves to 0.409 and 0.368 following photoinhibitory treatment of 6h and 8h and the CVs were increased from 0.8% to 22.2-22.3%. The Fv/Fm of 55-day old plants was reduced from 0.775 in the control leaves to 0.485 and 0.439 following photoinhibitory treatment of 10h and 12h, respectively. According to half diallel cross analysis, Reno and Dongbori 1 (highly resistant to photoinhibition) was dominant, but Oweolbori (susceptible to photoinhibition) was recessive, and photoinhibition showed partial dominance with highly additive gene action. Dongbori 1 showed the greatest GCA effects for photoinhibition, and GCA/SCA ratios (8.7-22.3 times) indicated that the additive variance for the character was more important. Winter survival in barley crosses was positively correlated with resistance to photoinhibition and significantly fitted by linear regression ($R^2$=0.751$^{**}$-0.779$^{**}$). The chlorophyll fluorescence measured by Fv/Fm has been found to be highly inheritable and very useful in evaluating relative levels of freezing resistance in barley.ley.

• Korean Journal of Environmental Agriculture
• /
• v.26 no.3
• /
• pp.239-245
• /
• 2007

The effect of ultraviolet-B (UV-B) radiation on photosynthesis was studied by the simultaneous measurements of $O_2$ evolution and chlorophyll (Chl) fluorescence in tobacco leaves. When the tobacco leaves were teated with UV-B (1 $W{\cdot}m^{-2}$), the maximal photosynthetic $O_2$, evolution (Pmax; 4.60 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) at 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) was decreased with increasing time of UV-B treatment showing 80% decline after 4 h treatment. Chl fluorescence parameters were also affected by ultraviolet-B. Fo was increased while both Fm and Fv were decreased, resulted in the decreased of photochemical efficiency of PSII (Fv/Fm). Non-radiative dissipation of absorbed light as heat as estimated as NPQ (Fm/Fm' - 1) was also decreased with increasing time of UV-B treatment while the extent of photochemical quenching (qP) was not changed. Thus, the ratio of (1-qP)/NPQ parameter was also increased with increasing time of UV-B treatment indicating PSII is under the threat of photoinhibition. The result indicate that UV-B primarily decreases the capacity to dissipate excitation energy by trans-thylakoid pH, which in turn inhibits PSII activity.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2019.10a
• /
• pp.60-60
• /
• 2019

개비자나무[Cephalotaxus harringtonia (Knight ex Forbes) K. Koch]와 비자나무[Torreya nucifera (L.) Siebold & Zucc.]의 3년생 실생묘를 유리온실에 재배하면서 실험재료로 사용하였다. 실내의 광량을 측정하여 10, 50, 100 및 200 PPFD (${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$)로 설정하였다. 광량을 제외한 광주기(12/12 h), 온도($25{\pm}1^{\circ}C$), 습도($55{\pm}3%$) 및 관수(1회/3일)주기를 일정하게 유지시킨 밀실에서 8주간 재배하였다. 유리온실에서 재배중인 식물과 광량별 처리구의 초장, 줄기직경, 엽수, 엽장, 엽폭, 엽록소함량(SPAD) 및 광화학반응을 평가하였다. 개비자나무의 생육결과, 모든 광량조건에서 줄기직경과 엽록소함량이 증가하는 경향을 보였으며, 초장, 엽폭의 경우 대조구와 유의한 차이가 없었다. 스트레스지수(Fm/Fo), 최대양자수율(Fv/Fm) 및 광계II 성능지수(Pi_Abs)는 대조구에 비해 모든 광량에서 증가하는 경향을 나타냈다. 10 PPFD의 광량을 제외한 처리구에서 재배된 비자나무의 초장, 줄기직경, 엽장, 엽폭은 대조구와 유사한 경향을 나타냈다. 한편, 엽수와 엽록소함량은 대조구에 비해 우수하였다. Fm/Fo, Fv/Fm, Pi_Abs 및 비광학적 에너지의 손실(DIo/RC)은 모든 광량처리구에서 대조구에 비해 유의적으로 높은 측정값을 나타냈다.

• Journal of Plant Biology
• /
• v.38 no.1
• /
• pp.11-18
• /
• 1995

Mercury-induced changes in Chl a fluorescence induction kinetics of scratched barley leaf segments were dependent on the presence of light. By the treatment of 50$\mu$M HgCl2 under light condition, Fm and Fp were decreased. However, they were not significantly reduced under dark condition even after 2 h of mercury treatment. Under dark condition the decrease in variable fluorescence (Fv) after P transient was blocked within 20 min of the treatment. The analysis of fast fluorescence rise curve suggests that the inhibitory site of mercury under both light and dark conditions is not at QB binding site and the inhibition does not involve the increase in inactive PSII centers. Under light condition the decrease in Fp was partially recovered by addition of 50 $\mu$M NH2OH. These results suggest that a major inhibitory site of mercury under dark condition is at the reducing side of PSII and the site under light condition is at the oxidizing side of PSII possibly in addition to the one under dark condition. Under both light and dark conditions, energy-dependent quenching(qE) was alomost completely repressed within 20 min of mercury treatment and noticible change in Fo was not observed. The qE repression is probably due to the blockage of transthylakoid ΔpH formation.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.43 no.3
• /
• pp.177-182
• /
• 2023

Iron (Fe) is a vital element for plants and other organisms, involving in several physiological processes including respiration, chlorophyll biosynthesis, and photosynthesis. Unfortunately, how Fe accumulation regulates in response to light quality has not been well established in plants. Therefore, the aim of the study was to explore the mechanism of Fe homeostasis by light quality. In this study, we found morpho-physiological attributes were significantly improved in response to blue (λmax: 450) compared to white (λmax: 500) and red (λmax: 660) light. The root-shoot length, plant biomass, photosynthesis efficiency (Fv/Fm) and leafgreen (SPAD) significantly declined in response to white and red light. However, these parameters were improved and iron deficiency was substantially alleviated by blue light exposure in alfalfa seedlings. This study might be useful to the forage breeders and farmers for improving alfalfa yield and nutritional benefits.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2020.08a
• /
• pp.67-67
• /
• 2020

Though there is an on-going need for the diversity of ornamental plants for in-door environment, their growth and stress adaptability in comparatively low light intensity condition require further studies for implementation. Here investigates the growth and chlorophyll fluorescence parameters of Farfugium japonicum (L.) Kitam, Liriope muscari (Decne.) L.H.Bailey and Acorus gramineus Aiton under several light intensities which were based on common in-door environment. The growth measurement of the plants included the quantity, length, width and SPAD value of the leaves. Calculated values of Fm/Fo, Fv/Fm, Pi_Abs, ETo/RC and DIo/RC were used as the parameters of the chlorophyll fluorescence under 10, 50, 100 and 200 PPFD (μmol·m^-2·s^-1) light intensities. In-door plants group was put in a closed room allowing no other light sources for 10 weeks and the control group was put in glass-greenhouse for the same period. The overall in-door growth of L. muscari was not significantly different in all light intensities compared to the control group and even showed the higher SPAD values. Also, an increasing tendency of Pi_Abs value under 10 to 100 PPFD was observed implying that L.muscari could adapt well to in-door environment. Measurement of A. gramineus growth mostly showed the highest values in the control group especially in the number of the leaves. Nevertheless, chlorophyll fluorescence parameters showed no significant value difference between in-door and the control groups and thus, A. gramineus might have possibility of successful adaptation to in-door environment. F. japonicum showed deficient growth in plant height and leaf length compared to the control but, it seemed to be able to sustain ornamental value under in-door light intensities. Furthermore, Pi_Abs and DIo/RC values were increased under in-door light conditions suggesting potential adaptability of F. japonicum.