• Plant Biotechnology Reports
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• v.5 no.2
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• pp.169-175
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• 2011

In this study, the JIP test was exploited to assess drought-tolerance of transgenic rice overexpressing OsNAC10. Two types of promoters, RCc3 (root-specific) and GOS2 (constitutive), were used to drive the transcription factor OsNAC10, a gene involved in diverse functions including stress responses. Three-month-old plants were exposed to drought for 1 week and their fluorescence kinetics was evaluated. Our results showed that drought-treated non-transgenic plants (NT) have higher fluorescence intensity at the J phase (2 ms) compared to transgenic plants, indicating a decline in electron transport beyond the reduced plastoquinone ($Q_A^-$). As manifested by negative L bands, transgenic plants also showed higher energetic connectivity and stability over NT plants under drought conditions. Also, the pool size of the end electron acceptor at the photosystem I was reduced more in NT than in transgenic plants under drought conditions. Furthermore, the transgenic plants had higher $PI_{total}$, a combined parameter that reflects all the driving forces considered in JIP test, than NT plants under drought conditions. In particular, the $PI_{total}$ of the RCc3:OsNAC10 plants was higher than that of NT plants, which was in good agreement with their differences in grain yield. Thus, the JIP test proved to be practical for evaluating drought-tolerance of transgenic plants.

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

• Korean Journal of Medicinal Crop Science
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• v.28 no.6
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• pp.412-420
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• 2020

Background: Measurement of chlorophyll fluorescence (CF) is useful for detection the ability of plants to tolerate environmental stresses such as drought, and excessive sunlight. Cnidium officinale Makino is highly sensitive to water stress and excessive sunlight. In this study, we evaluated the effect of soil water and shade treatment on the photosynthesis and leaf temperature change of C. officinale. Methods and Results: C. officinale was cultivated under uniform irrigation for 1 week drought stress (no watering) for 6 days. A significant decrease in CF was observed on the 5th day of withholding water (approximately 6% of soil water content) regardless of shading. Notably, the Rfd_lss parameter (CF decrease rates) with and without shade treatment was reduced by 73.1% and 56.5% respectively, at 6 days compared with those at the initial stage (0 day). The patterns of the degree of CF parameters corresponded to those of the soil water content and difference between leaf temperature (Ts) and air temperature (Ta). Meanwhile, CF parameters recovered to the 3 - 4 days levels after re-watering, while the soil water potential was completely restored. The suitable soil water content for C. officinale optimal growth was between -5 kPa and -10 kPa in this experiment. Conclusions: Lack of soil water in the cultivation of C. officinale, even with shading, decreased latent heat cooling through transpiration. As a result, heat dissipation declined, and the plant was subjected to drought stress. Soil water content plays a major role in photosynthesis and leaf temperature in C. officinale.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.55-55
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• 2020

This study investigated the growth and chlorophyll fluorescence reactions of three Ardisia genus grown under various indoor light intensity conditions with the aim of evaluating their suitability as indoor plants. Young seedlings of A. crispa (Thunb.) A.DC., A. pusilla DC., and A. japonica (Thunb.) Blume were used in the experiment. The plants were cultivated indoors for 10 weeks under different light intensities: 10, 50, 100, and 200 PPFD (μmol·m^-2·s^-1), and their growth was compared with that of plants cultivated in a greenhouse during the same period (mean value 236.8±20.4 PPFD at noon). Also, chlorophyll fluorescence analysis was investigated with a portable PAM fluorometer. The indoor plants were maintained at 12/12 h photoperiod, temperature at 25±1℃, and humidity at 55±3%. Irrigation frequency (once every three days) was the same for the indoors and the greenhouse. The results of growth in three Ardisia plants showed that almost all parameters except leaf number and chlorophyll content had similar levels regardless of light intensity. A. crispa and A. pusilla plants grown in 200 PPFD were investigated to have low chlorophyll contents. Meanwhile, chlorophyll fluorescence parameters differed based on light levels. In A. crispa, the Fv/Fm (0.77), DIo/RC (0.47) and Fm/Fo (4.77) parameters tended to be poor at 200 PPFD compared to those at other light intensities. Similarly, the DIo/RC, Fm/Fo, and Pi_Abs parameters of A. pusilla plant (200 PPFD) are 0.45, 4.48 and 2.42, respectively, which can be considered stress. The analysis of fluorescence in A. japonica showed that all parameters except ETo/RC had similar levels regardless of light intensity. The ETo/RC parameter was 0.49 and 0.72 in the control plants and plants 200 PPFD, respectively, which was lower than those in plants at other light intensities. Therefore, it seems that the relatively high light intensity acted as a stressor for Ardisia plants.

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.209-217
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• 1990

Intramolecular excimer formation with 1,3-di(1-pyrenyl)propane (Py-3-Py) and fluorescence polarization with 1,6-diphenyl-1,3,5-hexatriene (DPH) were used to evaluate the effects of barbiturates on the bulk fluidity of the model membranes of phosphatidylethanolamine fraction of synaptosomal plasma membrane vesicles (SPMVPE) isolated from bovine cerebral cortex. In the SPMVPE, barbiturates decreased the excimer to monomer fluorescence intensity ratio (I'/I) of Py-3-Py and increased the fluorescence polarization (P), anisotropy (r), limiting anisotropy $(r_{8})$, order parameter (S) and rotational relaxation time $({\bar{P}})$ of DPH in a dose-dependent manner. The relative potencies of barbiturates to order the SPMVPE were in the order: pentobarbital > hexobarbital > amobarbital > phenobarbital. Hence, it is concluded that barbiturates have ordering effects on the SPMVPE. And the membrane-ordering potencies of barbiturates appear to be correlated with the potencies for enhancement of GABA-stimulated chloride influx and with the anesthetic effects of barbiturates.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.264-271
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• 2016

The objective of this study was to determine the growth and light utilization efficiency of garden plants in shade area through chlorophyll fluorescence reaction analysis. Ten garden plants was grown for 75 days under 50% and 80% shading conditions. Under shading, $ET2_O/RC$, the fluorescence parameter related to electron-transport in photosystem II, was effectively enhanced. However, the electron transport flux until PSI acceptors per reaction center ($RE1_O/RC$) was reduced. These changes in photochemical parameters evoked a decrease in performance index (PI) and driving force (DF) of electron transport flux. In addition, some photochemical parameters such as $F_V$, $FV/F_O$, $RE1_O/RC$, $ET2_O/RC$, $PI_{TOTAL\;ABS}$, and $DF_{TOTAL\;ABS}$ were found to be important for shade tolerance. Three species (Pachysandra terminalis Siebold & Zucc, Physostegia virginiana L., and Carex maculata Bott) were found to be shade tolerant. Based on these results, shading factor index (SFI) deduced from photochemical parameters is useful for evaluating of shading stress of garden plants.

• Journal of the Korean Chemical Society
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• v.25 no.3
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• pp.183-189
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• 1981

Iron and titanium, the major constituents in iron ores, were X-ray spectrometrically determined by using the dilution parameter method. A standard and samples possessing a similar composition were diluted with the diluent $ZrO_2$ to their proper respective ratios. After measuring the intensity of the fluorescent X-ray, the dilution parameter was calculated from the following equation. $Pa=\frac{\frac{I_{as}}{(I_{as})_d}}{D-1}{^{-1}}$The dilution parameters were used to correct the difference between the matrix effect of the standard and that of the sample. The content of the major constituents was calculated, without using any standard calibration curves, from the following equation;$W_a=W_a^*{\cdot}{\frac{I_as}{I_{as}^*}{\cdot}\frac{P_a^*}{P_a}$where asterisks indicate the standard. The results agreed with those of the wet analysis within 2% of relative error, and the precision of the experiment was also tolerably good.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.130-137
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• 2023

By using XRF (X-ray fluorescence), this study investigates the variation of chemical properties in cement pastes at elevated temperatures. High-temperature conditions were prepared by using an electric furnace, planning a total of 11 target temperatures ranging from room temperature to 1000 ℃. A standard library of geo-quant basic was applied for the analysis of 12 elements in cement paste, including Ca, Si, Al, Fe, S, Mg, Ti, Sr, P, Mn, Zn and K. The results revealed that, as the temperature increased, the proportion of each element in the cement paste also increased. With the exception of a few elements present in extremely low amounts in the cement pastes, the variation in the composition ratio of most elements exhibited a strong correlation with temperature, with an R-squared value exceeding 0.98. In this study, cement pastes exposed to normal and high-temperature environments were compared. The authors established that the reasons for the different results in this comparison can be explained from the same perspective as when comparing raw cement with cement paste. Furthermore, this study discussed the potentially most dominant parameter when investigating the properties of cement paste using XRF.

• Proceedings of the Speleological Society Conference
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• 1993.07a
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• pp.163-172
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• 1993

Cheju island is situated at about 90km south of southern most tip of the Korean peninsula. Its shape is an ellips with size of 80$\times$40$km^2$, and it is characterized by a symmetrical form whose peak is Mt. Halla (1950m). Major chemical composition of the rock samples from Manjang gul cave is determined by XRF using the fundamental parameter method consisting of fully auto quantitative analysis, semi quantitative analysis (order estimation) and group quantitative analysis. Judging from chemical composition ($SiO_2 = 53.07Wt% Fe_2 O_3=11.34Wt%, MgO=6.48Wt%, Na_2 O=3.07Wt%, K_2 O=1.05Wt%$), this rocks may belong to non alkalic basalt. K-Ar ages of two rocks samples from the Manjang gul cave are also determined. The discrepancy of K-Ar ages is found. They are 0.03Ma and 0.42Ma, respectively. This paper describes some problems experienced in dating young volcanic rocks and then discusses chemical composition, X-ray fluorescence analysis and the age of the formation of a lava tunnel such as Manjang gul cave in cheju Island.

• Journal of Photoscience
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• v.12 no.2
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• pp.57-61
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• 2005

The ground and excited state dipole moments of Coumarin 450 (C 450) laser dye were measured at room temperature in several solvents of varying dipole moments. The ground state dipole moment (${\mu}_g$) is estimated by using the modified Onsagar model and the excited state dipole moments (${\mu}_e$) were estimated by the method of solvatochromism as well as by utilizing the microscopic solvent polarity parameter ($E^N_T$). Further, the deviation of some of the points from the linearity of the $E^N_T$ versus Stokes shift indicates the existence of specific type of solute-solvent interaction. The excited state dipole moment of C 450 were found to be higher than those of the ground state and is interpreted in terms of the resonance structure of the molecule. A reasonable agreement has been observed between the values obtained by the method of solvatochromism and modified Onsagar model. It is observed that, corresponding to cyclohexane solution, the fluorescence maxima shift towards the red region with increasing the polarity of the solvents, hence the transition involved are of ${\pi}-{\pi}^*$ type.