• Journal of Plant Biology
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• 제31권2호
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• pp.131-141
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• 1988

The effects of decursinol and decursin on chloroplast-mediated electron transport and phosphorylation in barley seedlings were investigated in comparison with coumarin in the dark or light. The changes of CP-complexes were also studied. Decursinol, decursin and coumarin caused marked inhibitory effects on germination of seed and electron transport and phosphorylation activity of seedlings. The following order of inhibitory effectiveness was exhibited; decursinol>coumarin>decursin. Loss of chlorophyll and decrease of electron transport activity were retarded in the dark, but were reversely accelerated in the light by these three chemicals. The changes of CP-complex patterns were also similar to effects on chlorophyll content and the electron transport activity. These opposite effect in the dark and light suggest that these three chemicals act as natural growth retardants rather than cytokinins or growth inhibitors.

• 한국환경과학회지
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• 제1권1호
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• pp.1.1-11
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• 1992

To find heavy metal-specific effects on the photosynthetic apparatus of higher plants, we investigated effects of $CuCl_2$, HgCl_2$ and $ZnCl_2$ on electron transport activity and chlorophyll fluorescence induction kinetics of chloroplasts isolated from barley seedlings. Effects on some related processes such as germination, growth and photosynthetic pigments of the test plants were also studied. Germination and growth rate were inhibited in a concentration-dependent manner by these metals. Mercury was shown to be the most potent inhibitor of germination, growth and biosynthesis of photosynthetic pigments of barley plants. In the inhibition of electron transport activity, quantum yield of PS II, and chlorophyll fluorescence induction kinetics of chloroplasts isolated from barley seedlings, mercury chloride showed more pronounced effects than other two metals. Contrary to the effects of other two metals, mercury chloride increased variable fluorescence significantly and abolished qE in the fluorescence induction kinetics from broken chloroplasts of barley seedlings. This increase in variable fluorescence is due to the inhibition of the electron transport chain after PS ll and the following dark reactions. The inhibition of qE could be attributed to the interruption of pH formation and do-epoxidation of violaxathin to zeaxanthin in thylakoids by mercury. This unique effect of mercury on chlorophyll fluorescence induction pattern could be used as a good indicator for testing the presence and/or the concentration of mercury in the samples contaminated with heavy metals.

• Journal of Ginseng Research
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• 제14권2호
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• pp.135-141
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• 1990

In order to elucidate the mechanism of the leaf-burning disease of ginseng (Panax ginseng C.A. Meyer), the relationships between thylakoid membrane peroxidation and chlorophyll bleaching were investigated in comparison with the ones of soybean (Glycine max L). When I measured the rate of lipid peroxidation in the thylakoids of ginseng and soybean by irradiation of light(60 w.m-2), it was identified that, the remarkably lower rate of lipid peroxidation was found in the ginseng thylakoid than the case of soybean. When lipid peroxidation of ginseng thylakoid was induced in the dark, chlorophyll contents of thylakoid was not changed. The results suggest that lipid peroxidation does not affect the chlorophyll bleaching in ginseng thylakoid. Thylakoid membrane peroxidation as well as chlorophyll bleaching was closely related with photosynthetic electron transport. But, according to the quenching experiment active oxygen species induced lipid peroxidation may be different species in the case of chlorophyll bleaching.

• Journal of Plant Biology
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• 제26권2호
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• pp.91-99
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• 1983

The formation of chlorophyll-protein complexes (CP-complexes) during the greening of rape cotyledons (Brassica napus cv. Yongdang) was investigated by the SDS-polyacrylamide gel electrophoresis. The total chlorophyll content and Chl a/b ratio were also determined. In addition, the effects of dark treatment on the CP-complex patterns during greening have been examined with respect to their photosynthetic electron transport activity. Greening has brought about the increasein total chlorophyll content and the decrease in Chl a/b ratio, but there have been no changes in Chl a/b ratio after 24 hrs of greening. The light-harvesting chlorophyll a/b-protein complex (LHCP-complex0 was predominant during the initial greening period. Thereafter, the amout of chlorophyll a-protein complex (CP I-complex) was gradually increased. Twenty-four-hr dark treatment immediately after illumination for 6 hrs and 12 hrs resulted in the increase of the Chl a/b ration and the CP I complex, otherwise the decrease of the LHCP-complex. The LHCP/CP I ratio was gradually decreased with further greening, and appeared no change after 48 hrs illumination. The investigation of the photosynthetic electron transport activity indicated that photosystem (PS) II activity (H2Olongrightarrowp-PD*＋FeCy**) did not change, but the activity of PS I was increased suddenly due to the dark treatment. The data suggests that the increase of CP I-complex may result in that of P-700, that is, the increase of PS I activity.

• Journal of Plant Biology
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• 제31권3호
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• pp.217-226
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• 1988

Effects of simazine [2-chloro-4,6-bis(methylamino)-s-triazine] on the photochemical reactions of isolaed spinach chloroplasts and crude thylakoids of Anabaena inequalis UTEX B-381 were compared. Simazine inhibited photosynthetic O2 evolution and increased the chlorophyll fluorescence in whole cells of Anabaena. The electron transfer from diphenylcarbazide to 2,6-dichlorophenolindophenol was inhibited by simazine treatment in spinach chloroplasts, but not in crude thylakoids of Anabaena. In spinach chloroplasts, the chlorophyll fluorescence was increased by simazine treatment in the presence of diphenylcarbazide and ferricyanide, but not in the presence of diphenylcarbazide and silicomolybdate. In crude thylakoids of Anabaena, simazine treatment did not increase the chlorophyll fluorescence in the presence of either diphenylcarbazide and silicomolybdate, or diphenylcarbazide and ferricyanide. There results suggest that the inhibitory site of simazine on photosynthetic electron transport chain of anabaena is different from that of spinach chloroplasts. And there may be a possiblity that the inhibition site of simazine in Anabaena lies on the donor side of photosystem II, before the site of electron donation by diphenylcarbazide.

• Journal of Plant Biology
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• 제34권3호
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• pp.215-221
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• 1991

Photoxynthetic properties of polyvinylalcohol (PVA)-immobilized chloroplast especially regarded to stability of photosynthetic electron transport and the fluorescence induction pattern were studied. When isolated spinach chloroplasts were immobilized with PVA, it showed good preservation of photosynthetic electron transport activity, especially PS II activity, during storage at -15$^{\circ}C$, 4$^{\circ}C$ and 2$0^{\circ}C$. And immobilized chloroplasts revealed similar thermostability of whole chain electron transport to free chloroplsts. And the absorption peak of red band of chloroplasts showed the blue-shift of 2-4 nm after immobilization. Fv/Fm ratio of chlorophyll fluorescence slightly decreased after immobilization. White light pulse after continuous light do not induced the additional fluorescence rise. This means chlorophyll fluorescence at room temperature reached to Fmax under continuous light in the immobilized chloroplasts. It seems that PVA may be a good candidate for immobilization matrix for the preservation of photosynthetic function of thylakoids and for the continuous use of chloroplast membranes of higher plants for solar energy storage and conversion.

• 한국환경과학회지
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• 제6권4호
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• pp.369-378
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• 1997

The effects of various intensity of W-B on barley seeding were investigated by PS I and II activities and chlorophyll fluorescence. The Inhibitory effect of UV-B radiation on electron transport activity was Increased as the intensity of UV-B Irradiation was increased. Especially, PS I is more sensitive to UV-B radiation than PS I is. By the addition of uncle electron donor, DPC, to the chloroplasts of the barley seedlings treated with UV-B, the photoreduction of DCPIP was recovered by only 1 IBI on electron transport activity. However, the activity of PS II was Inhibited by 45% by the treatment with UV-B, but recovered it only 11% by the addition of DPC. These suggest that other sites besides the oxidation site of PS II may be affected more by UV-B Irradiation. As the intensify of UV-B was Increased, Fo was Increased while Fv was decreased, and thus Fv/Fm was decreased. This means that photochemical efficiency was reduced. With this parameters, it might be that UV-B radiation affected adversely to around PS II.

• 한국토양비료학회지
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• 제46권6호
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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.

• ALGAE
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• 제25권2호
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• pp.89-97
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• 2010

To test the feasibility of using chlorophyll ${\alpha}$ fluorescence to assess the establishment success of seagrass transplants, photosynthetic characteristics of eelgrass Zostera marina transplants were measured using a Diving-pulsed amplitude modulation fluorometer in Jindong Bay on the southern coast of Korea. Maximum quantum yield ($F_v/F_m$), photosynthetic efficiency ($\alpha$), saturating irradiance ($E_k$) and maximum electron transport rate ($ETR_{max}$) of transplants and reference plants in a nearby transplant site were measured using the fluorometer for 5 months. Additionally, shoot morphology, individual shoot weight and productivity of transplants and reference plants were also monitored. Shoot height, leaf weight and productivity of transplants were significantly reduced during the first two or three months after transplantation compared to those of reference plants, and then increased to the levels of reference plants Characteristics of chlorophyll a fluorescence, including $F_v/F_m$, $\alpha$, $E_k$ and $ETR_{max}$ of transplants were also significantly reduced in the initial period, but recovered slightly sooner than shoot morphology or leaf productivity. These results indicated that after transplantation, Z. marina transplant photosynthesis recovered faster than shoot morphology, biomass or productivity. Thus, chlorophyll a fluorescence can be used as an indicator for early assessment of the status of eelgrass transplants without destructive sampling.

• Journal of Korean Society for Atmospheric Environment
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• 제22권E2호
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• pp.89-98
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• 2006

Two tobacco cultivars (Nicotiana tabacum L.), Bel-B and Bel-W3, tolerant and sensitive to ozone, respectively, were grown in a greenhouse supplied with charcoal filtered air and exposed to 200 ppb ozone for 4 hr. Effects on chlorophyll fluorescence, net photosynthesis, and stomatal conductance are described. Quantum yield was calculated from chlorophyll fluorescence and the initial slope of the assimilation-light curve measured by the gas exchange method. Only the sensitive cultivar, Bel-W3, developed visual injury symptoms on up to 50% of the $5^{th}$ leaf. The maximum net photosynthetic rate of ozone-treated plants was reduced 40% compared to control plants immediately after ozone fumigation in the tolerant cultivar; however, photosynthesis recovered by 24 hr post fumigation and remained at the same level as control plants. On the other hand, ozone exposure reduced maximum net photosynthesis up to 50%, with no recovery, in the sensitive cultivar apparently causing permanent damage to the photosystem. Reductions in apparent quantum efficiency, calculated from the assimilation-light curve, differed between cultivars. Bel-B showed an immediate depression of 14% compared to controls, whereas, Bel-W3 showed a 27% decline. Electron transport rate (ETR), at saturating light intensity, decreased 58% and 80% immediately after ozone treatment in Bel-B and Bel-W3, respectively. Quantum yield decreased 28% and 36% in Bel-B and Bel-W3, respectively. It can be concluded that ozone caused a greater relative decrease in linear electron transport than maximum net photosynthesis, suggesting greater damage to PSII than the carbon reduction cycle.