Mode of Action and Metabolism of Diquat and Paraquat

Funderburk, H. H.

doi:10.2307/4040748

Cited by 66 publications

(37 citation statements)

References 22 publications

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“…Maximum stimulation, which is two to three times RD (the control rate of dark respiration), is usually reached within 120 min, and at 500 min rates are still often double those of the control. Similar results are given by 5 X 1O-3 M diquat, but here the maximum stimulation is of the order of 5R D. Mees (1960) and Funderburk and Lawrence (1964) also reported stimulation of respiration of bean roots and Lemna fronds respectively by diquat in darkness. …”

Section: (A) Effect Of Diquat Treatment In Darkness On Oxygen Uptakesupporting

confidence: 73%

The Effects of the Dipyridyl Diquat on the Metabolism of Chlorella Vulgaris III. Dark Metabolism: Effects on Respiration Rate and the Path of Carbon

Stokes¹,

Turner²

1971

Aust. Jnl. Of Bio. Sci.

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When O. vulgaris is treated in complete darkness with diquat at concentrations which are toxic in the light, there is a rapid and large stimulation of oxygen uptake with no significant alteration in the R,Q. If the O. vulgaris has been darkened for some hours before the addition of diquat there is a two-to threefold stimulation of the rate of respiration, which subsequently remains constant or falls only slowly for up to 500 min. With pre-illuminated or glucose-treated O. vulgaris, diquat causes a much greater stimulation of dark respiration, rapidly declining to near the control rate. Tracer studies with 14C02 and [14C]glucose show that diquat when added in darkness to O. vulgaris accelerates the breakdown of starch and the loss of 14C from most intermediate substances of carbohydrate metabolism. The exception to this is the rapid accumulation of 14C counts in citric acid. These results are discussed and a mechanism for the action of diquat in darkness is proposed.

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Section: (A) Effect Of Diquat Treatment In Darkness On Oxygen Uptakesupporting

confidence: 73%

The Effects of the Dipyridyl Diquat on the Metabolism of Chlorella Vulgaris III. Dark Metabolism: Effects on Respiration Rate and the Path of Carbon

Stokes¹,

Turner²

1971

Aust. Jnl. Of Bio. Sci.

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“…a bipyridinium herbicide diquat and a diphenyl-ether herbicide oxyfluorfen) were considered in an attempt to confirm the effect of CmWE4 on the reduction of oxidative damage (Funderburk and Lawrence 1964;Sherman et al 1991). It was hypothesized that the mechanism of action of CmWE4 could be differentiated because PQ shares a mode of action with DQ but not with OF.…”

Section: Physical Properties Of Cmwe4mentioning

confidence: 99%

“…Paraquat (PQ) is a non-selective quaternary nitrogen herbicide that is used widely in crop fields as well as in non-arable areas because it works very fast on a broad range of photosynthesizing green plants (Dodge 1975;Funderburk and Lawrence 1964). In the presence of light, PQ targets photosystem I and inhibits the reduction of NADP to NADPH.…”

Section: Introductionmentioning

confidence: 99%

Ameliorative effects of squash (Cucurbita moschata Duchesne ex Poiret) leaf extracts on oxidative stress

et al. 2012

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This study screened paraquat-tolerant plants among 10 plant species, including monocots and dicots angiosperms. Squash (Cucurbita moschata Duchesne ex Poiret) and kidney bean (Phaseolus vulgaris L.) plants exhibited the highest photooxidation-tolerant phenotypes upon a foliar treatment with paraquat. A foliar treatment with paraquat pre-mixed with leaf water extracts from the squash plant significantly alleviated paraquat-induced oxidative damage in maize, but this was not the case after a treatment with the hydrophobic phase of the leaf extracts. In particular, the water extract from young leaves (4th true leaf) of squash plants conferred tenfold higher tolerance to oxidative damage in paraquat-treated leave tissues compared to paraquat-only treatment. This tolerance was tightly linked not only to the increased amounts of ascorbic acid and dehydroascorbate antioxidants in the damaged leaves, but also to the reduced chlorophyll loss, lipid peroxidation, and cellular electrolyte leakage. Moreover, the protective effects of the water extract were apparent when using another bipyridyl herbicide, diquat, but not with a diphenyl-ether herbicide, oxyfluorfen. On the other hand, pre-treatment with the extract prior to the onset of drought or cold stress had no significant antioxidative effect on the treated tissues.

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“…Paraquat should not be used in cassava during the first three months of growth due to the presence of photosynthetic tissue a t the base of the stems and the dangers of herbicide absorption and translocation leading to subsequent death of the tissues. The relationship between the mode of action of paraquat and photosynthesis has been discussed by (Mees, 1960;Funderburk and Lawrence, 1964;Calderbank, 1968). However, as soon as the basal 15-20 cms of the stems have become lignified (3 months of age), paraquat can be used with complete safety, as it does not penetrate lignified tissue.…”

Section: Introductionmentioning

confidence: 97%

Chemical Weed Control in Cassava using Paraquat

Harper

1974

PANS Pest Articles & News Summaries

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Paraquat applied as a directed inter-row spray gave economical control of weeds in cassava for a period of three months or more. Applications were made at rates of 0.2-0.4 kglha post-emergence in young cassava of 3 months or more with 15-20 cm of brown bark at the base of the stems; a repeat application was made after an interval of 10-14 days. Usually, one further spray was required to obtain acceptable weed control until harvesting, weed control being facilitated by the increased shade given by the developing crop canopy. PANS 20: 185 -189, 1974.

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Mode of Action and Metabolism of Diquat and Paraquat

Cited by 66 publications

References 22 publications

The Effects of the Dipyridyl Diquat on the Metabolism of Chlorella Vulgaris III. Dark Metabolism: Effects on Respiration Rate and the Path of Carbon

The Effects of the Dipyridyl Diquat on the Metabolism of Chlorella Vulgaris III. Dark Metabolism: Effects on Respiration Rate and the Path of Carbon

Ameliorative effects of squash (Cucurbita moschata Duchesne ex Poiret) leaf extracts on oxidative stress

Chemical Weed Control in Cassava using Paraquat

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