Sulphur dioxide effects on cell structure and photosynthetic performance in the liverwort Frullania dilatata

2000 ◽  
Vol 78 (1) ◽  
pp. 98-104 ◽  
Author(s):  
Cristina Gimeno ◽  
Vicente I Deltoro
Keyword(s):  
Sulphur Dioxide ◽  
Cell Injury ◽  
Cell Structure ◽  
Electron Flow ◽  
Photosynthetic Performance ◽  
Fluorescence Induction ◽  
Visible Injury ◽  
Induction Kinetics ◽  
Direct Exposure ◽  
Flow Through

The effects of SO2 exposure, carried out in controlled-environment cuvettes, on the photosynthetic performance of the liverwort Frullania dilatata (L.) Dum. were investigated by means of chorophyll a fluorescence induction kinetics and gas-exchange measurements. Additionally, visible-injury symptoms developing in leaves as a result of exposure to the pollutant were quantified and described. The adverse effects of SO2 on photosynthesis could be seen as (i) a decreased electron flow through photosystem II (PSII), (ii) an increased degree of closure of PSII centres, (iii) a lowered capacity for dissipative processes, and (iv) reduced net CO2 assimilation rates. Additionally, SO2 induced severe cell injury that ranged from cells without oil bodies to cells with collapsed plasma membrane and disorganized organelles. The distribution pattern of injuries in the shoots ofF. dilatata suggests that SO2-induced damage is related to the degree of direct exposure to the pollutant. It is possible that, because this liverwort grows in dense patches with overlapping branches, some protection is conferred to basal leaves.Key words: Frullania dilatata, chlorophyll fluorescence, sulphur dioxide, fumigation, cellular injury.

Photosynthetic Characteristics of Three Strains of Cyanobacteria Grown under Low-or High-C02 Conditions

1996 ◽  
Vol 51 (1-2) ◽  
pp. 40-46 ◽  
Author(s):  
Shigetoh Miyachi ◽  
Joachim Bürger ◽  
Kiriakos Kotzabasis ◽  
Jens Thielmann ◽  
Horst Senger
Keyword(s):  
Oxygen Evolution ◽  
Dissolved Inorganic Carbon ◽  
Electron Flow ◽  
Liquid Nitrogen Temperature ◽  
Fluorescence Induction ◽  
Anabaena Variabilis ◽  
Photosynthetic Oxygen Evolution ◽  
Induction Kinetics ◽  
Fluorescence Induction Kinetics ◽  
Photosynthetic Oxygen

Abstract Quantum requirements of photosynthetic oxygen evolution at 679 nm, fluorescence emis­sion spectra at liquid nitrogen temperature (77 K) and fluorescence induction kinetics in the presence of DCM U, were measured in the cyanobacteria Anabaena variabilis M3, Anabaena variabilis ATCC 29413 and A nacystis nidulans R2, each grown under low-or high-CO2 conditions. Low -CO2 grown cells of the cyanobacteria showed a higher quantum requirement of photosynthetic oxygen evolution and a higher ratio o F710-740 to F680-700 fluorescence and a lower variable fluorescence in the presence of DCMU than high-CO2 grown cells. These findings indicate a change in excitation energy distribution in favour of photosystem I. The result might be an enhancement in ATP formation caused by cyclic electron flow which in turn provokes dissolved inorganic carbon (DIC) accumulation in these low-CO2 grown cells.

Action of Methylthiopyrimidine Experimental Herbicides as Diuron-Like Inhibitors of Photosynthesis

1985 ◽  
Vol 40 (5-6) ◽  
pp. 388-390 ◽  
Author(s):  
Jean-M arc Ducruet ◽  
René Scalla
Keyword(s):  
Binding Site ◽  
Electron Flow ◽  
Fluorescence Induction ◽  
Site Structure ◽  
Structure Activity Relationships ◽  
Induction Kinetics ◽  
Fluorescence Induction Kinetics ◽  
Structure Activity ◽  
Derivatives Of ◽  
Steric Hindrances

Abstract Derivatives of 6-chloro-5-methylthiopyrimidines provide potent inhibitors of the photosynthe­tic electron flow, which act like Diuron on fluorescence induction kinetics and competitively displace it from its binding site. Structure-activity relationships show that, unlike triazines, ac­tivities of 2-or 4-alkylamino derivatives are restricted by steric hindrances. Decreases in inhibit­ory activities of these compounds observed in triazine-resistant chloroplasts are lower than de­creases reported for triazines themselves.

scholarly journals Increased CO2 Relevant to Future Ocean Acidification Alleviates the Sensitivity of a Red Macroalgae to Solar Ultraviolet Irradiance by Modulating the Synergy Between Photosystems II and I

2021 ◽  
Vol 12 ◽  
Author(s):  
Di Zhang ◽  
Juntian Xu ◽  
Sven Beer ◽  
John Beardall ◽  
Cong Zhou ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Ocean Acidification ◽  
Electron Flow ◽  
Photosynthetic Performance ◽  
Red Macroalgae ◽  
Flow Through ◽  
Commercially Important ◽  
Ultraviolet Irradiance ◽  
Algal Thalli

While intertidal macroalgae are exposed to drastic changes in solar photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) during a diel cycle, and to ocean acidification (OA) associated with increasing CO2 levels, little is known about their photosynthetic performance under the combined influences of these drivers. In this work, we examined the photoprotective strategies controlling electron flow through photosystems II (PSII) and photosystem I (PSI) in response to solar radiation with or without UVR and an elevated CO2 concentration in the intertidal, commercially important, red macroalgae Pyropia (previously Porphyra) yezoensis. By using chlorophyll fluorescence techniques, we found that high levels of PAR alone induced photoinhibition of the inter-photosystem electron transport carriers, as evidenced by the increase of chlorophyll fluorescence in both the J- and I-steps of Kautsky curves. In the presence of UVR, photoinduced inhibition was mainly identified in the O2-evolving complex (OEC) and PSII, as evidenced by a significant increase in the variable fluorescence at the K-step (Fk) of Kautsky curves relative to the amplitude of FJ−Fo (Wk) and a decrease of the maximum quantum yield of PSII (Fv/Fm). Such inhibition appeared to ameliorate the function of downstream electron acceptors, protecting PSI from over-reduction. In turn, the stable PSI activity increased the efficiency of cyclic electron transport (CET) around PSI, dissipating excess energy and supplying ATP for CO2 assimilation. When the algal thalli were grown under increased CO2 and OA conditions, the CET activity became further enhanced, which maintained the OEC stability and thus markedly alleviating the UVR-induced photoinhibition. In conclusion, the well-established coordination between PSII and PSI endows P. yezoensis with a highly efficient photochemical performance in response to UVR, especially under the scenario of future increased CO2 levels and OA.

Non-Invasive Monitoring of the Light-Induced Cyclic Photosynthetic Electron Flow during Cold Hardening in Wheat Leaves

2006 ◽  
Vol 61 (9-10) ◽  
pp. 734-740 ◽  
Author(s):  
Simona Apostol ◽  
Gabriella Szalai ◽  
László Sujbert ◽  
Losanka P. Popova ◽  
Tibor Janda
Keyword(s):  
Winter Wheat ◽  
Electron Flow ◽  
Wheat Variety ◽  
Fluorescence Induction ◽  
Chlorophyll Fluorescence Induction ◽  
Light Conditions ◽  
Non Invasive ◽  
Photosynthetic Electron Flow ◽  
Temperature Hardening ◽  
Wheat Leaves

AbstractThe effect of irradiance during low temperature hardening was studied in a winter wheat variety. Ten-day-old winter wheat plants were cold-hardened at 5 °C for 11 days under light (250 μmol m-2 s-1) or dark (20 μmol m-2 s-1) conditions. The effectiveness of hardening was significantly lower in the dark, in spite of a slight decrease in the Fv/Fm chlorophyll fluorescence induction parameter, indicating the occurrence of photoinhibition during the hardening period in the light. Hardening in the light caused a downshift in the far-red induced AG (afterglow) thermoluminescence band. The faster dark re-reduction of P700+, monitored by 820-nm absorbance, could also be observed in these plants. These results suggest that the induction of cyclic photosynthetic electron flow may also contribute to the advantage of frost hardening under light conditions in wheat plants.

scholarly journals The C Termini of Constitutive Nitric-oxide Synthases Control Electron Flow through the Flavin and Heme Domains and Affect Modulation by Calmodulin

2000 ◽  
Vol 275 (38) ◽  
pp. 29225-29232 ◽  
Author(s):  
Linda J. Roman ◽  
Pavel Martásek ◽  
R. Timothy Miller ◽  
Dawn E. Harris ◽  
Melissa A. de la Garza ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Electron Flow ◽  
Nitric Oxide Synthases ◽  
Flow Through

Electron Flow through Geometrical Discontinuity in Coaxial Magnetically Insulated Transmission Lines

2000 ◽  
Vol 39 (Part 1, No. 9A) ◽  
pp. 5280-5286 ◽  
Author(s):  
Kazuki Hiraoka ◽  
Mitsuo Nakajima ◽  
Makoto Shiho ◽  
Kazuhiko Horioka
Keyword(s):  
Transmission Lines ◽  
Electron Flow ◽  
Flow Through ◽  
Geometrical Discontinuity
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