• Journal of Environmental Science International
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• v.30 no.7
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• pp.547-555
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• 2021

To compare the vitality among cool-season turfgrasses under summer weather conditions and to obtain information to improve the management of turfgrasses in golf courses and sports fields., the chlorophyll fluorescence of three cool-season turfgrasses commonly planted on golf courses in the Jeju area was measured. The turfgrasses were perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and creeping bentgrass (Agrostis palustris Huds.). In perennial ryegrass and Kentucky bluegrass, the chlorophyll index was low in early summer and high in late summer. In creeping bentgrass, it remained low throughout the study. Fo tended to be low in the early summer and high in late summer in the three turfgrasses. However, the difference in F_o between late summer and early summer was markedly higher in perennial ryegrass than in Kentucky bluegrass or creeping bentgrass. F_m tended to be low in early summer and high in late summer, without obvious differences among the three turfgrasses. F_v/F_m, a measure of photochemical efficiency, was also low in early summer and high in late summer in the three turfgrasses. However, F_v/F_m in late summer was mostly higher in Kentucky bluegrass and creeping bentgrass than in perennial ryegrass, indicating that the former are more resistant to the high temperature and humidity of late summer. Furthermore, Kentucky bluegrass had a high chlorophyll index in late summer and would be most resistant to the harsh conditions of late summer.

• Korean Journal of Weed Science
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• v.15 no.3
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• pp.224-231
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• 1995

Paraquat, the representative bipyridilium herbicide, has high phytotoxic activity through generating toxic oxygen species such as superoxide, hydrogen peroxide and hydroxy radical. The response patterns of plants to paraquat were various. It was assumed that the different response was derived from different antioxidative mechanisms including antioxidative enzymes and antioxidant. Paraquat treatment increased reducing sugar content and malondialdehyde formation at 35 days after treatment in a dose-dependent manner but chlorophyll content decreased. Glutathione content increased by paraquat treatment and tolerant species showed more glutathione content than susceptible species. Superoxide dismutase activity increased with the increase in paraquat concentration and that was higher in tolerant species than susceptible species. Photosynthetic activity(PSII activity) was affected by paraquat, so the susceptible species showed more reduced oxygen evolving capacity than tolerant species. Catalse, NADPH-cytochrome C reductase, and malate dehydrogenase, the enzymes tested in this study, showed that the activities decreased by paraquat treatment. Further studies are necessary to determine whether antioxidative system cause the tolerance to paraquat.

• Horticultural Science & Technology
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• v.33 no.6
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• pp.829-838
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• 2015

Garlic (Allium sativum L.), one of the oldest cultivated crops, is the most widely used Allium species belonging to the family Lilliaceae. In this study, growth characteristics, photosystem II activity, and antioxidative enzyme activity were investigated in five temperatures ($10-30^{\circ}C$) during early growth stage of garlic to determine the optimum temperature for cultivation and assess the effects of high temperature on early growth of garlic. Vegetative growth (e.g., shoot height, number of leaves) of garlic plants was greater in the temperature ranges of $15-25^{\circ}C$. However, dry weight (of shoot, bulb, and total plant) of garlic was significantly greater at $20^{\circ}C$, compared to either below or above $20^{\circ}C$. $F_v/F_o$ and $F_v/F_m$ values were highest at $15-20^{\circ}C$, and decreased above $25^{\circ}C$. The chlorophyll a fluorescence induction OKJIP transient was also considerably affected by high temperature; the fluorescence yields $F_i$ and $F_P$ decreased considerably above $25^{\circ}C$, with the increase of $F_k$ and $W_k$. Activities of catalase and superoxide dismutase in leaves and peroxidase in roots were high in $20-25^{\circ}C$, and decreased significantly in $30^{\circ}C$. These results indicate that a growth temperature of $30^{\circ}C$ inhibits early growth of garlic and that it is desirable to culture garlic plants near $20^{\circ}C$. Fluorescence parameters such a $F_v/F_o$, $F_v/F_m$, $F_k$, $ET_o/CS_m$, and $PI_{abs}$ were significantly correlated with dry weight of whole garlic plants (p < 0.01), indicating that these fluorescence parameters can be used for early assessment of high temperature effects even though the damage to the plant is not very severe.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2951-2957
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• 2015

The development of worldwide harmful algal blooms(HAB) is a serious problem for public health and fisheries industries. To evaluate the algicidal impact on the HAB species, algicide thiazolidinedione derivative (TD49) and yellow clay were examined, which is focus on assess the algicidal effects and inhibition to photosynthesis of HAB species. To obtain the detailed information, we analyzed the viability of target species related to activity Chl. a, photosynthetic efficiency($F_v/F_m$), and electron transport rate(ETR). Culture experiment was conducted to evaluate the algicidal effects of three harmful species(raphidophyceae Heterosigma akashiwo, Chattonella marina, and dinophyceae Heterocapsa circularisquama) and one non-harmful species (cryptophyceae Rhodomonas salina). Our experiments revealed that three HAB species were easily destroyed of the cell walls after TD49 dosing. Also, they had significantly reducing values of active Chl. a, $F_v/F_m$, and ETR, due to the damage of photosystem II by inter-cellular disturbance. As a result, the algicidal effect(%) for the three HABs were as follows, in the order of greatest to the least: H. circularisquama> C. marina> H. akashiwo. However, the algicidal effect for yellow clay remained to be <30% (p>0.01), implying that it may not have damaged the photosystem II. On the other hand, non-HAB R. salina was promoted at both TD49 and yellow clay treatments. Our results demonstrated that the TD49 is a good agent for the control of HABs H. akashiwo, C. marina, and H. circularisquama, whereas the yellow clay would not be suitable for the field application based on our experimental results.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.2
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• pp.156-163
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• 2005

This study was conducted to compare the physiological and biochemical responses of P. orientalis and L. tulipifera in response to ozone. One-year-old seedlings of P. orientalis and L. tulipifera were exposed to 100 ppb ozone concentration for 2, 4, or 8 hr/day for 1 week. Photosynthesis, stomatal conductance and ozone uptake rate were measured daily, and chlorophyll fluorescence, carboxylation efficiency, chlorophyll content, and SOD activity were measured after 1 week. In P. orientalis, photosynthesis and stomatal conductance were not decreased in the 2h/day ozone treatment, but the L. tulipifera response was more sensitive even in the 2h/day ozone treatment. Increased treatment time decreased photosynthesis and stomatal conductance. Chlorophyll fluorescence was not significantly different among treatment times. However, carboxylation efficiency decreased with increased treatment time, and L. tulipifera was more sensitive than P. orientalis. Chlorophyll content did not differ with species or treatment time. SOD activity response was greater in L. tulipifera than in P. orientalis, increasing to $131\%$ of pretreatment observations. Therefore it was concluded that L. tulipifera was more responsive and had lower ozone tolerance than P. orientalis.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.659-664
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• 2013

The aim of this study is to determine the drought stress index through photochemical analysis in red pepper (Capsiumannuum L.). The photochemical interpretation was performed in the basis of the relation between Kautsky effect and Photosystem II (PSII) following the measurement of chlorophyll, pheophytin contents, and $CO_2$ assimilation in drought stressed 5-week-old red pepper plants. The $CO_2$ assimilation rate was severely lowered with almost 77% reduction of chlorophyll and pheophytin contents at four days after non-irrigation. It was clearly observed that the chlorophyll fluorescence intensity rose from a minimum level (the O level), in less than one second, to a maximum level (the P-level) via two intermediate steps labeled J and I (OJIP process). Drought factor index (DFI) was also calculated using measured OJIP parameters. The DFI was -0.22, meaning not only the initial inhibition of PSII but also sequential inhibition of PSI. In real, most of all photochemical parameters such as quantum yield of the electron transport flux from Quinone A ($Q_A$) to Quinone B ($Q_B$), quantum yield of the electron transport flux until the PSI electron acceptors, quantum yield of the electron transport flux until the PSI electron acceptors, average absorbed photon flux per PSII reaction center, and electron transport flux until PSI acceptors per cross section were profoundly reduced except number of QA reducing reaction centers (RCs) per PSII antenna chlorophyll (RC/ABS). It was illuminated that at least 6 parameters related with quantum yield/efficiency and specific energy fluxes (per active PSII RC) could be applied to be used as the drought stress index. Furthermore, in the combination of parameters, driving forces (DF) for photochemical activity could be deduced from the performance index (PI) for energy conservation from photons absorbed by PSII antenna until the reduction of PSI acceptors. In conclusion, photochemical responses and their related parameters can be used as physiological DFI.

• Journal of Environmental Science International
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• v.19 no.12
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• pp.1323-1334
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• 2010

The effect of nitric oxide (NO) on antioxidant system and protective mechanism against oxidative stress under UV-B radiation was investigated in leaves of maize (Zea mays L.) seedlings during 3 days growth period. UV-B irradiation caused a decrease of leaf biomass including leaf length, width and weight during growth. Application of NO donor, sodium nitroprusside (SNP), significantly alleviated UV-B stress induced growth suppression. NO donor permitted the survival of more green leaf tissue preventing chlorophyll content reduction and of higher quantum yield for photosystem II than in non-treated controls under UV-B stress, suggesting that NO has protective effect on chloroplast membrane in maize leaves. Flavonoids and anthocyanin, UV-B absorbing compounds, were significantly accumulated in the maize leaves upon UV-B exposure. Moreover, the increase of these compounds was intensified in the NO treated seedlings. UV-B treatment resulted in lipid peroxidation and induced accumulation of hydrogen peroxide ($H_2O_2$) in maize leaves, while NO donor prevented UV-B induced increase in the contents of malondialdehyde (MDA) and $H_2O_2$. These results demonstrate that NO serves as antioxidant agent able to scavenge $H_2O_2$ to protect plant cells from oxidative damage. The activities of two antioxidant enzymes that scavenge reactive oxygen species, catalase (CAT) and ascorbate peroxidase (APX) in maize leaves in the presence of NO donor under UV-B stress were higher than those under UV-B stress alone. Application of 2-(4-carboxyphenyl)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3- oxide (PTIO), a specific NO scavenger, to the maize leaves arrested NO donor mediated protective effect on leaf growth, photosynthetic pigment and free radical scavenging activity. However, PTIO had little effect on maize leaves under UV-B stress compared with that of UV-B stress alone. $N^{\omega}$-nitro-L-arginine (LNNA), an inhibitor of nitric oxide synthase (NOS), significantly increased $H_2O_2$ and MDA accumulation and decreased antioxidant enzyme activities in maize leaves under UV-B stress. This demonstrates that NOS inhibitor LNNA has opposite effects on oxidative resistance. From these results it is suggested that NO might act as a signal in activating active oxygen scavenging system that protects plants from oxidative stress induced by UV-B radiation and thus confer UV-B tolerance.

• Korean Journal of Medicinal Crop Science
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• v.28 no.1
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• pp.1-8
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• 2020

Background: This study was conducted to investigate the effects of NaCl concentration on the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of Crepidiastrum sonchifolium. Methods and Results: As treatments, we subjected C. sonchifolium plants to four different concentrations of NaCl (0, 50, 100 and 200 mM). We found that the photosynthetic parameters maximum photosynthesis rate (P_{N max}), net apparent quantum yield (Φ), maximum carboxylation rate (V_cmax), and maximum electron transport rate (J_max) were significantly reduced at an NaCl concentration greater than 100 mM. In contrast, there was an increase in water-use efficiency with increasing NaCl concentration, although in terms of growth performances, leaf dry weight, root dry weight, stem length, and total dry weight all decreased with increasing NaCl concentration. Furthermore, leakage of electrolytes, as a consequence of cell membrane damage, clearly increased in response to an increase in NaCl concentration. Analysis of the polyphasic elevation of chlorophyll a fluorescence transients (OKJIP) revealed marked decrease in flux ratios (Φ_PO, Ψ_O and Φ_EO) and the PI_abs, performance index in response to treatment with 200 mM NaCl, thereby reflectings the relatively reduced state of photosystem II. This increase in fluorescence could be due to a reduction in electron transport beyond Q^-_A. We thus found that the photosynthetic parameters, chlorophyll fluorescence and growth characteristics of C. sonchifolium significantly increased in response to treatment with 200 mM NaCl. Conclusions: Collectively, the findings of this study indicate that C. sonchifolium shows relatively low sensitivity to NaCl stress, although photosynthetic activity was markedly reduced in plants exposed to 200 mM NaCl.

• Journal of Plant Biology
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• v.38 no.4
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• pp.373-380
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• 1995

Photoinhibition of photosystem (PS) n was induced in primary leaves of 25 day-old peppers grown $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1},\;at\;25^{\circ}C$. The modulation of PSII functionality in vivo was induced by varying both irradiance ($0-3000\;{\mu}molm^{-2}{\cdot}s^{-1}$) and duration (0-70 min) of light treatment. The functionality of PSII was investigated in terms of photochemical efficiency of PSII (Fv/Fm) and quantum yield of $O_2$ evolution, and expressed as a function of photon exposure [$mol\;photons{\cdot}m^{-2}$, the product of irradiance and duration of light treatment (Bell and Rose, 1981)]. Contrary to the linear decline of Fv/Fm ratio showing 50% decreases by absorption of $10\;mol\;photons{\cdot}m^{-2$, quantum yield of $O_2$ evolution decreased biphasically with increasing photon exposure, showing 50% decreases by absorption of $5.5\;mol\;photons{\cdot}m^{-2}$. Treatment of low temperature at $15^{\circ}C$ for 30 min alone did not affect the functionality of PSII, but high temperature ($45^{\circ}C$) significantly inactivated PSII activity. However, when Jeaves of pepper were subjected to low or high temperature in the presence of light, PSII was substantially photoinactivated. These results suggest the presence of different photoinhibitory mechanisms at low and high temperature.rature.

• 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.