• Journal of Plant Biology
• /
• v.37 no.1
• /
• pp.37-42
• /
• 1994

Correlative changes between photosynthetic O2 exchange rates and room temperature Chl fluorescence were investigated in wheat (Triticum aestivum L.) chloroplasts treated with high temperature for 5 min. With increasing treatment temperature, photosynthetic O2 evolution rate mediated by PSII was decreased, showing 50% inhibition at 38$^{\circ}C$ (I50). But PSI activity measured by O2 uptake rates was stimulated as a function of increasing temperature. Dark level fluorescence (Fo)-temperature (T) analysis showed that fluorescence rising temperature (Tr), critical temperature (Tc), and peak temperature (Tp) was 38, 43, and 52$^{\circ}C$, respectively. Quenching analysis of Chl fluorescence showed that both the oxidized fraction of plastoquinone (qQ) and degree of thylakoid membrane energization (qNP) increased up to 4$0^{\circ}C$ and then declined dramatically. These results suggest that Tr is correlated with temperature showing a 50% of inhibition of photosynthesis and under mild high temperature stress, qNP is worth regarding as indicator for heat-induced damage of photosynthesis.

• Journal of Ginseng Research
• /
• v.13 no.2
• /
• pp.158-164
• /
• 1989

In order to determine the relationships between the lea(-burning disease and the light harvesting chlorophyll-protein (LHCP) complex in Panax ginseng C. A. Meyer, we investigated the chlorophyll-protein (CP) complex of the thylakoid membrane and its characteristics. In P. ginseng four Cp-complex bands determined by non-denaturing SDS-PAGE were identified CP I'(containing reaction center of photosystem I and LHCP I antennae), CP I (reaction center of photosystem I) LHCP II** (oligoform of LHCP II), and LHCP II (photosystem II antennae, CP 26 and CP 29) by Bassis and Dunahay's procedures. Under our experimental condition, the CP I band was only observed in P. ginseng and the band intensity of LHCP II** in P ginseng was higher than in spinach and soybean. There were differences in the absorption and fluorescence spectra and chlorophyll a/b ratio of the CP-complex bands between P. ginseng and other Plants. The Polypeptidr content of P. ginseng thylakoid was lower than in spinach and soybean thylakoid, and the Polypeptide profiles of P. ginseng was low band intensity, especially about 29-35 kD, 55 kD, and 60 kD, compared to spinach and soybean. The inhibitory effects of 2,5-dimethylfuran, specific singlet oxygen ($^1O_2$) quencher, showed that singlet oxygen destroyed 60% of chl.a, 90% of chl.b and 70% of carotenoid in bleaching P. ginseng with leaf-burning disease.

• ALGAE
• /
• v.20 no.2
• /
• pp.121-125
• /
• 2005

The modern integrated fish-seaweed mariculture has been tested to reduce the environmental impacts of an intensive fed culture. To obtain the best seaweed bioremediation performance, the effects of therapeutants used for fish disease control on the selected seaweed species should be considered. As a selected seaweed, Porphyra yezoensis was tested with six commercial antibiotics including erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, doxycycline, pefloxacin, and amoxicillin trihydrate under the batch incubation at a photon flux density of 10 $\mu$mol ${\cdot}m^{-2}\;{\cdot}\;s^{-1}$ at 15$^{\circ}C$. Among the tested commercial antibiotics, erythromycin thiocyanate_A, erythromycin thiocyanate_B, oxytetracycline, and doxycycline showed decreases in Fv/Fm, the photochemical efficiency of photosystem II, with a dose-dependant and time-dependant manner. From the quenching analysis of chlorophyll fluorescence, three differential patterns were observed in the antibiotics-treated Porphyra: (1) high nonphotochemical quenching (NPQ) and low photochemical quenching (qP) in the cases of Erythromycin thiocyanate_B and amoxicillin trihydrate, (2) high NPQ and high qP in the case of pefloxacin and (3) low NPQ and low qP in the case of oxytetracycline. These results indicated that antibiotics affected in various ways on the photosynthetic apparatus, reflecting differential lesion sites of antibiotics. In addition, the rates of ammonium uptake also decreased with a decrease of Fv/Fm in P. yezoensis thalli treated with erythromycin thiocyanate_B and oxytetracycline. Therefore, the four antibiotics mentioned could affect the bioremediation capacity of the selected seaweed species in the integrated fish-seaweed mariculture system due to the decrease of photosynthetic activity and the simultaneous decrease of ammonium uptake.

• The Korean Journal of Ecology
• /
• v.19 no.2
• /
• pp.151-163
• /
• 1996

To investigate the early symptoms of light-chilling, alterations of chlorophyll fluorescence transients were monitored in cucumber (Cucumis sativus L. cv. Ilmichungjang) leaves. During 24 h chilling, decreases in (Fv)m/Fm, qE and qQ, and an increase in Fo were observed. The chilling effects were not recovered at room temperature, and a significant increase in Fo was observed during the recovery period. After 6 h chilling, ‘dip’(D) level of the transients became obscure, and the negative slope after ‘peak’(P) disappeared. The first derivative (dFv/dt) of the fast fluorescence rise curve was used to obtain more accurate information about the changes in the transients. The maximal rate of the fluorescence increase in the D-p rise curve (Fr) has been the most frequently used chilling stress indicator. However, a correct value of Fr could not be measured when the D level became obscure. This problem was overcome by introducing a new indicator, HFr (dFv/dt at Fv = 1/2 (Fv)m), and HFr gave very similar values to Fr. To monitor the changes in curvature around D level, another new parameter, ${\Delta}S$(D-Fr), was also introduced. These three parameters decreased very sensitively during light-chilling. In addition, increases in these parameters were observed during the first 2 h chilling, but this increase in Fr was also observed in pea leaf discs dark-chilled for 15 min, suggesting that this very early change is a common response to chilling in both pea and cucumber leaves. Quenching coefficients were also very sensitive to chilling, especially qE. Discussion on the usage of these parameters as chilling stress indicators is given in the text.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.120-120
• /
• 2022

Agrivoltaic System (AVS) was introduced with the concept that it could generate electricity by using the extra light remain after crops use for photosynthesis in farm, which can earn additional income. However, crop yield was declined under the AVS condition due to the decrease in light energy. In the past, many researchers have been studied about crop states under shading conditions. However, the phenomenon of partial shading such as under the AVS is not well studied. In this study, to figure out the response of crop under the different light conditions, the electron transport rate (ETR) and non-photochemical quenching (NPQ) of rice was investigated using the chlorophyll fluorescence measurement. Also, physiological changes of crops under the shading conditions were investigated. The growth experiment under partial shading under AVS and overall shading which made of 35% shade cloth was conducted to understand the eco-physiological responses of rice to light in terms of the photosynthesis. Under the shading conditions, SPAD value and chlorophyll contents were higher, but the leaf thickness was lower than control. The overall shading condition show lower ETR than others during the growing season. In contrast, NPQ was higher than other treatments. This means the available light energy cannot contribute to photosynthesis under the shading condition.

• Korean Journal of Environmental Biology
• /
• v.19 no.1
• /
• pp.43-48
• /
• 2001

Chlorophyll fluorescence of needles of Korean fir (Abies koreana) plants and environmental factors of their natural habitat were investigated in order to obtain the information for environmental adaptation and conservation of Korean fir plants. The photochemical efficiency of photosystem II, Fv/Fm, of Korean fir needles was significantly low (0.19-0.36) in the winter, whereas it was high (0.8-0.86) in the summer. The Fv/Fm value of the winter was slightly higher at mid-day than at dawn, suggesting that mid-day environmental conditions of the winter were favorable on needles of Korean fir plants. In contrast, the mid-day Fv/Fm value of the summer maintained high (around 0.8). It indicates that mid-day environmental conditions of the summer did not induce photodamage, although it caused a slight decrease in the Fv/Fm values. The non-photochemical fluorescence quenching (NPQ) of Korean fir needles was very low (0-0.01) all through the day in the winter. However, it was high (0.76) at mid-day in the summer. These results suggest that Korean fir plants have a system for the protection of PS II from mid-day environmental stresses of the summer. In the winter, the Fv/Fm values were positively correlated with temperature, light intensity and relative humidity, although NPQ values showed no correlation with any of them. In the summer, the Fv/Fm values were positively correlated with relative humidity but negatively correlated with temperature and light intensity. These results indicate that increase of tempera-ture, light intensity and relative humidity lead to promotion of the photochemical efficiency in the winter and high temperature and light intensity may cause photoinhibition in the summer.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.23 no.3
• /
• pp.163-168
• /
• 2021

The growth experiment under shading condition has been performed to understand the eco-physiological responses of crops to light in terms of photosynthesis. There are two types of shading: overall shading and partial shading. In this study, the chlorophyll fluorescence of soybean was observed under the overall shading of the box made by polyresin and the partial shading at agrivoltaic system. The overall shading condition during vegetative growth induced lower SPAD and Electron transport rate (ETR). These lower values recovered after removal of shading box. However, the Non-photochemical fluorescence quenching (NPQ) became lower under overall shading and higher under partial shading. Such increase in NPQ limited crop photosynthesis even though the ETR was almost same to the control without shading treatment. Under the condition of partial shading, the values of SP AD and ETR for soybean did not change. However, the NPQ was higher than control condition. This suggests that the crop photosynthesis under both types of shading would be decreased by different eco-physiological processes which are the lower ETR in overall shading and the higher NP Q in partial shading despite the reduced light under shading conditions.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.23 no.2
• /
• pp.100-107
• /
• 2021

An agrivoltaic system (AVS) is a system of innovation that comprises productions of photovoltaic power and agricultural crops on the same area. However, the decline in crop yield will be fatally occurred because the pigments of crop absorbs less light energy under AVS. In addtion, the photosynthetic capacity of crop grown under the partial shading of AVS is not well reported. In this study, the electron transport rate (ETR) and non-photochemical fluorescence quenching (NPQ) of soybean and rice under the AVS in Boseong and Naju was investigated using chlorophyll fluorescence measurement. The ETR value of soybean and rice under AVS were not significantly differed by location. It represents that the photophosphorylation rate of the crops is not critically different. It means that the decreases in total photosynthesis under AVS were mostly affected by the amount of light absorbed by leaves. Under AVS the photosynthesis of crops will be lower than field crops grown in open fields. This is because the crops under AVS observed higher NPQ, which means that the available energy cannot distribute to photophosphorylation reaction.

• Journal of Plant Biotechnology
• /
• v.37 no.4
• /
• pp.567-573
• /
• 2010

To ascertain the effect of over-expressed maize calreticulin in tomato plant on tobamovirus movement in addition to validating potentiality of the gene (ZmCRT) as a means for the virus-resistance resource, four ZmCRT-expressing homozygous lines were generated from the T0 plants as using an Agrobacterium-mediated transformation, nucleic acid analyses, and a conventional breeding method. Of them, a line was subjected to the bioassay for tolerances to tobacco mosaic virus-U1 (TMV-U1) and tomato mosaic virus (ToMV) followed by RT-PCR and a chlorophyll fluorescence quenching analyses. Both transgenic plants transcribing ZmCRT and wild-type plants showed no symptom by 20 days after viruses inoculation, however the photosystem II quantum yield parameter measured from the upper leaves of ToMV-inoculated plants revealed that ZmCRT transgenic plants have higher photosynthetic ability than wild-type ones at that time, which indirectly implies that over-expressed ZmCRT product acts as a barrier to the cell-to-cell and/or systemic movement of ToMV. Moreover, ZmCRT transgenic plants showed remarkably longer shoot length than wild-type ones in 40 days after TMV-U1 or ToMV inoculation each, which might be resulted from higher photosynthetic ability during the phase not yet showing any external symptoms. Collectively, over-expressed ZmCRT protein in tomato plants is able to interrupt the systemic movement of infected TMV-U1 and ToMV even though not perfect.

• Journal of Environmental Science International
• /
• v.11 no.10
• /
• pp.1023-1030
• /
• 2002

The effects on photosynthesis of NaCl(0, 0.2, 0.4, 0.6, 0.8 or 1.0 M) were examined in etiolated barley seedlings. Chlorophyll(Chl) a, Chl b and carotenoid contents, Chl a fluorescence and quenching coefficients of Chl fluorescence have been determined in the primary leaves of etiolated barley seedlings cultivated under low light(60 $\mu$㏖ $m^{-2}\;s^{-1}$). Chl a, b, and carotenoid contents were decreased remarkably in comparison with the control at 0.4 M NaCl. However, the value of Fo and Fv were decreased at 0.6 M NaCl and the ratio of Fv/Fm were deceased at 1.0 M NaCl. Chlorophyll synthesis was seriously inhibited from 0.4 M NaCl, and the photosynthetic electron transport system was inhibited from 0.6 M NaCl. Quantum of photosystem II reaction center was inhibited at 1.0 M NaCl. The effects of NaCl on the Chl content were raised in a 6 hrs, but the effects of NaCl on the value of Fo, Fv and Fv/Fm were raised in 30 hrs. The value of qP was decreased in comparison with the control at all concentrations, but there was a small change in the value qE. These results provide evidence that NaCl inhibited effects of various concentration of NaCl were inhibited quinone redox, however, proton gradient between thylakoid membranes was little damaged.