Drought-induced changes in photosynthetic electron transport in maize probed by prompt fluorescence, delayed fluorescence, P700 and cyclic electron flow signals

2019 ◽  
Vol 158 ◽  
pp. 51-62 ◽  
Author(s):  
Ronghua Zhou ◽  
Xin Kan ◽  
Jianjian Chen ◽  
Heliang Hua ◽  
Yue Li ◽  
...  
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Delayed Fluorescence ◽  
Cyclic Electron Flow ◽  
Prompt Fluorescence ◽  
Induced Changes

Inhibition of Photosynthetic Electron Transport by Halogenated 4-Hydroxy-pyridines

1985 ◽  
Vol 40 (5-6) ◽  
pp. 391-399 ◽  
Author(s):  
A. Trebst ◽  
B. Depka ◽  
S. M. Ridley ◽  
A. F. Hawkins
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Electron Flow ◽  
Essential Element ◽  
Photosynthetic Electron Transport ◽  
Cyclic Electron Flow ◽  
Acceptor Side

Abstract Herbicidal halogen substituted 4-hydroxypyridines are inhibitors of photosynthetic electron flow in isolated thylakoid membranes by interfering with the acceptor side of photosystem II. Tetrabromo-4-hydroxypyridine, the most active compound found, has a pI50-value of 7.6 in the inhibition of oxygen evolution in both the reduction of an acceptor of photosystem I and an acceptor of photosystem II. The new inhibitors displace both metribuzin and ioxynil from the membrane. The 4-hydroxypyridines, like ioxynil, have unimpaired inhibitor potency in Tristreated chloroplasts, whereas the DCMU-type family of herbicides does not. It is suggested that 4-hydroxypyridines are complementary to phenol-type inhibitors, and a common essential element is proposed. The 4-hydroxypyridines do not inhibit photosystem I or non-cyclic electron flow through the cytochrome b/f complex. But they do have a second inhibition site in photosynthetic electron transport since they inhibit ferredoxin-catalyzed cyclic electron flow, indicating an antimycin-like property. A comparison of the in vitro potency of the compounds with the in vivo potency shows no correlation. A major herbicidal mode of action of the group is related to the inhibition of carotenoid synthesis, and access to the chloroplast lamellae in vivo for inhibition of electron transport may be restricted.

Interaction of Photosystem II Herbicides with Bicarbonate and Formate in Their Effects on Photosynthetic Electron Flow

1984 ◽  
Vol 39 (5) ◽  
pp. 374-377 ◽  
Author(s):  
J. J. S. van Rensen
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Hill Reaction ◽  
Amaranthus Hybridus ◽  
Apparent Affinity ◽  
Photosynthetic Electron Flow ◽  
Different Characteristics ◽  
The Hill

The reactivation of the Hill reaction in CO2-depleted broken chloroplasts by various concentrations of bicarbonate was measured in the absence and in the presence of photosystem II herbicides. It appears that these herbicides decrease the apparent affinity of the thylakoid membrane for bicarbonate. Different characteristics of bicarbonate binding were observed in chloroplasts of triazine-resistant Amaranthus hybridus compared to the triazine-sensitive biotype. It is concluded that photosystem II herbicides, bicarbonate and formate interact with each other in their binding to the Qв-protein and their interference with photosynthetic electron transport.

Rewiring photosynthesis: a photosystem I-hydrogenase chimera that makes H2in vivo

2020 ◽  
Vol 13 (9) ◽  
pp. 2903-2914 ◽  
Author(s):  
Andrey Kanygin ◽  
Yuval Milrad ◽  
Chandrasekhar Thummala ◽  
Kiera Reifschneider ◽  
Patricia Baker ◽  
...  
Keyword(s):  
Electron Transport ◽  
Hydrogen Production ◽  
Photosystem I ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

Photosystem I-hydrogenase chimera intercepts electron flow directly from the photosynthetic electron transport chain and directs it to hydrogen production.

Inhibition by Tetranitromethane of Photosynthetic Electron Transport from Water to Photosystem II in Chloroplasts

1980 ◽  
Vol 35 (3-4) ◽  
pp. 293-297 ◽  
Author(s):  
P. V. Sane ◽  
Udo Johanningmeier
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Electron Flow ◽  
Ph Dependence ◽  
Photosynthetic Electron Transport ◽  
Donor Side ◽  
Ps Ii ◽  
Diphenyl Carbazide ◽  
Low Concentrations ◽  
Sh Group

Abstract Low concentrations (10 µM) of tetranitromethane inhibit noncyclic electron transport in spinach chloroplasts. A study of different partial electron transport reactions shows that tetranitromethane primarily interferes with the electron flow from water to PS II. At higher concentrations the oxidation of plastohydroquinone is also inhibited. Because diphenyl carbazide but not Mn2+ ions can donate electrons efficiently to PS II in the presence of tetranitromethane it is suggested that it blocks the donor side of PS II prior to donation of electrons by diphenyl carbazide. The pH dependence of the inhibition by this protein modifying reagent may indicate that a functional-SH group is essential for a protein, which mediates electron transport between the water splitting complex and the reaction center of PS II.

scholarly journals Photosynthesis Regulation in Response to Fluctuating Light in the Secondary Endosymbiont Alga Nannochloropsis gaditana

2019 ◽  
Vol 61 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Alessandra Bellan ◽  
Francesca Bucci ◽  
Giorgio Perin ◽  
Alessandro Alboresi ◽  
Tomas Morosinotto
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Incident Light ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Nannochloropsis Gaditana ◽  
Fluctuating Light ◽  
Light Fluctuations

Abstract In nature, photosynthetic organisms are exposed to highly dynamic environmental conditions where the excitation energy and electron flow in the photosynthetic apparatus need to be continuously modulated. Fluctuations in incident light are particularly challenging because they drive oversaturation of photosynthesis with consequent oxidative stress and photoinhibition. Plants and algae have evolved several mechanisms to modulate their photosynthetic machinery to cope with light dynamics, such as thermal dissipation of excited chlorophyll states (non-photochemical quenching, NPQ) and regulation of electron transport. The regulatory mechanisms involved in the response to light dynamics have adapted during evolution, and exploring biodiversity is a valuable strategy for expanding our understanding of their biological roles. In this work, we investigated the response to fluctuating light in Nannochloropsis gaditana, a eukaryotic microalga of the phylum Heterokonta originating from a secondary endosymbiotic event. Nannochloropsis gaditana is negatively affected by light fluctuations, leading to large reductions in growth and photosynthetic electron transport. Exposure to light fluctuations specifically damages photosystem I, likely because of the ineffective regulation of electron transport in this species. The role of NPQ, also assessed using a mutant strain specifically depleted of this response, was instead found to be minor, especially in responding to the fastest light fluctuations.

Mode of Inhibition of Photosynthetic Electron Transport by Substituted Diphenylethers

1981 ◽  
Vol 36 (9-10) ◽  
pp. 848-852 ◽  
Author(s):  
W. Draber ◽  
H. J. Knops ◽  
A. Trebst
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Thylakoid Membranes ◽  
Photosynthetic Electron Flow ◽  
Spinach Chloroplasts

Abstract Several substituted diphenylethers were found to be effective inhibitors of photosynthetic electron flow in isolated thylakoid membranes from spinach chloroplasts. T heir site of inhibition was localized with artificial acceptor and donor systems. The phenylether of an alkyl substituted nitrophenol is prim arely inhibiting electron flow after plastoquinone function whereas a dinitro-phenylether of a phenyl substituted nitrophenol is inhibiting before plastoquinone function. Therefore certain diphenylethers interfere with plastoquinone function at the oxidation or reduction site, depending on the substitution.

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