Mechanisms of Action of Herbicides

Moreland, Donald E.

doi:10.1146/annurev.pp.18.060167.002053

Cited by 156 publications

(113 citation statements)

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“…Some precaution should be taken when using DBMIB, because site of action is concentration dependent, as well as redox sensitive, where DBMIB becomes reduced under light and oxidised in the dark (Bukhov et al 2003). At low concentrations, DBMIB inhibits electron transport on the reducing side of the PQ, but at higher concentrations excess DBMIB will inhibit the Q B site of PSII, located on the oxidising side of the PQ (Moreland 1980;Rich et al 1991). To prevent fluorescence quenching from oxidised DBMIB, it can be used in conjunction with an excess of sodium ascorbate (Kufryk and Vermaas 2006).…”

Section: Inhibitors Of Linear Electron Transportmentioning

confidence: 99%

“…Uncouplers function by dissociating electron transport from ATP synthesis during photosynthetic phosphorylation (Moreland 1980;McCauley et al 1987). This is accomplished by dissipating the energised state (H + ) of the membrane (DpH) before the energy can be utilised in ADP phosphorylation (Moreland 1980) and thus prevent the formation of the trans-thylakoid DpH gradient.…”

Section: Electron Transport Uncouplersmentioning

confidence: 99%

“…This is accomplished by dissipating the energised state (H + ) of the membrane (DpH) before the energy can be utilised in ADP phosphorylation (Moreland 1980) and thus prevent the formation of the trans-thylakoid DpH gradient. In addition to this major effect on the energy budget of the cell, the electron flow continues but the collapsed proton gradient no longer regulates electron transport rate.…”

Section: Electron Transport Uncouplersmentioning

confidence: 99%

“…5) (Dan Hess 2000). MV 2+ is an extremely powerful electron acceptor, due to the nature of the bipyridinium salts, which temporarily become a stable radical with the addition of an electron, neutralising the positive charge of the cation (Moreland 1980;Peon et al 2001). MV 2+ oxidizes the primary acceptor (ferrodoxin) of linear electron transport, allowing a DpH to become established.…”

Section: Electron Acceptorsmentioning

confidence: 99%

See 3 more Smart Citations

Fluorescence as a Tool to Understand Changes in Photosynthetic Electron Flow Regulation

Ralph

Wilhelm

Lavaud

et al. 2010

Chlorophyll a Fluorescence in Aquatic Sciences: Methods and Applications

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Section: Inhibitors Of Linear Electron Transportmentioning

confidence: 99%

Section: Electron Transport Uncouplersmentioning

confidence: 99%

Section: Electron Transport Uncouplersmentioning

confidence: 99%

Section: Electron Acceptorsmentioning

confidence: 99%

See 2 more Smart Citations

Fluorescence as a Tool to Understand Changes in Photosynthetic Electron Flow Regulation

Ralph

Wilhelm

Lavaud

et al. 2010

Chlorophyll a Fluorescence in Aquatic Sciences: Methods and Applications

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“…Les herbicides inhibant le PS II en bloquant le transfert d'électrons, l'oxygène singulet va rester actif et entraînera la destruction oxydative des constituants du thylakoïde, dont les pigments. De plus, l'arrêt du transfert non-cyclique entraîne celui de la nitrite-réductase, ce qui génère une accumulation de nitrites toxiques (DUCRUET, 1991 ;MORELAND, 1967 ;TISSUT et SEVERIN, 1984).…”

Section: Mode D'actionunclassified

Les herbicides inhibateurs du photosystème II, effets sur les communautés algales et leur dynamique

Bérard¹,

Pelte

2005

rseau

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Nous présentons une revue bibliographique à propos des effets des herbicides inhibiteurs du Photosystème II (PS II) sur les communautés algales. Ces herbicides sont abondamment utilisés dans les pratiques phytosanitaires. Ils sont susceptibles de contaminer les milieux aquatiques et, étant donné leur mode d'action inhibitrice de la photosynthèse, ils peuvent agir directement sur les algues. De nombreuses études ont été réalisées afin d'évaluer l'impact des contaminations par ces herbicides sur les microphytes, en particulier leur effet sur la croissance et la physiologie de certaines algues (monocultures en laboratoire). D'autres études expérimentales et quelques rares in situ, ont porté sur l'impact des herbicides inhibiteurs de la photosynthèse sur la structure des peuplements algaux. Certaines tendances ont pu être ainsi dégagées quant à la sensibilité et la résistance aux herbicides des différentes espèces étudiées soit isolément, soit au sein des peuplements. Les herbicides inhibiteurs du PS II perturbent effectivement la structure des peuplements phytoplanctoniques de façon plus ou moins marquée. L'impact des herbicides sur les algues est variable selon la structure des peuplements (liée aux successions) et les paramètres environnementaux, notamment liés à la saison. Nous devons donc développer nos connaissances à propos des interactions entre toxiques et facteurs environnementaux sur des pas de temps correspondant non seulement aux rythmes des contaminations mais aussi aux rythmes des succesions alagles, car ces interactions sont susceptibles de réduire ou d'amplifier les conséquences d'une pollution par ces toxiques dans les milieux aquatiques.The aim of this paper is to present a review about the impact of Photo system II (PS II) inhibitors on algae communities. A brief discussion of the use in agriculture, the different chemical families, the photosynthetic inhibition effect and the occurrence of these compounds in aquatics systems is followed by the presentation of the impacts these herbicides have on algae. Many studies investigate the effects of PS II inhibitors on algae growth and physiology. The response to pollutants were studied by monitoring changes in terms of different parameters : chlorophyll fluorescence induction usually increases with PS II inhibitors. Concentration of pigments decreases with PS II inhibitors, but increases sometimes with low contaminations of these toxicants (it is probably an homeostasis effect). Pigment ratio can change with herbicide exposure. Primary production (measured by 14C incorporation or dissolved O2) usually decreases with PS II inhibitors. But, the " excretion " of dissolved organic compounds may increase with PS II inhibitors. These herbicides may alter or change cell morphology of algae. In consequence algae growth is inhibited by PS II inhibitors exposure. But growth inhibition varies, depending on each species' (and strain) sensibility or resistance to each herbicide. By this way, PS II inhibitors can affect the algae community structure. In consequence, ...

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Behavioural and histological effects of atrazine on freshwater molluscs (Physa acuta drap. andAncylus fluviatilis Müll. gastropoda)

1999

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This study examines the direct and indirect effects of atrazine on two grazer species— Physa acuta and Ancylus fluviatilis —as assessed by changes in mortality rates, biomass, searching behaviour and histological properties. No direct effects were observed in the acute toxicity test (48 h) with 0.02, 0.2, 2, 10 and 20 mg l−1 of atrazine. A chronic toxicity test (18 days) performed in six experimental channels with 15 μg l−1 of atrazine showed significant changes in grazer behaviour, increased searching velocity and different movement patterns in animals exposed to herbicide. No significant effects were observed in rates of mortality and biomass. Kidney cells of Physa acuta displayed an important cell lysis when animals were exposed to 0.1 mg l−1 of atrazine for 10 days, and this effect was not reversed after a decontamination process. These results provide evidence of behavioural and structural changes in freshwater molluscs due to a subacute atrazine concentration. Copyright © 1999 John Wiley & Sons, Ltd.

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Mechanisms of Action of Herbicides

Cited by 156 publications

References 0 publications

Fluorescence as a Tool to Understand Changes in Photosynthetic Electron Flow Regulation

Fluorescence as a Tool to Understand Changes in Photosynthetic Electron Flow Regulation

Les herbicides inhibateurs du photosystème II, effets sur les communautés algales et leur dynamique

Behavioural and histological effects of atrazine on freshwater molluscs (Physa acuta drap. andAncylus fluviatilis Müll. gastropoda)

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