Diquat enhancement of cupric ion toxicity

Swader, J. A.

doi:10.1016/0048-3575(78)90074-3

Cited by 3 publications

(6 citation statements)

References 22 publications

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“…Aliquots containing 19 X 10 5 algal cells with 18.9 J.1g chlorophyll were added to the oxygraph reaction cell and distilled water, pH 7.0, was used as the assay medium. These technqiues are similar to those reported previously (14). Isolation of leaf cells.…”

Section: Oxygraph Reactions Changes In O 2 Concentration Of the Reacsupporting

confidence: 89%

“…Evidence that R-24191 inhibited photosystem II was also provided by using DCIP as the electron acceptor to photosystem II (4,14,15). The photoreduction of DCIP by isolated chloroplasts was inhibited by lower concentrations of R-24191 (Table 4) than the O 2 evolution during CO 2 fixation by isolated leaf cells (Table 1), indicating the plasmalemma may have been a barrier to the movement of R-24191, or the phenylurea was binding to non-active sites in the leaf cells, or both.…”

Section: Resultsmentioning

confidence: 99%

“…Cblorella cultures. Chlorella was cultured and the cells counted as reported previously (3,14). The initial cell concentration in the growth experiment was 1 x 10 4 cells mr 1 .…”

Section: Methodsmentioning

confidence: 99%

“…Chlorophyll determination. Chlorophyll was extracted from Chlorella cells with hot 80% ethanol (3,14,15). Chlorophyll was extracted from chloroplasts with 80% (v/v) acetone.…”

Section: Oxygraph Reactions Changes In O 2 Concentration Of the Reacmentioning

confidence: 99%

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Inhibition of Photosystem II andChlorellaGrowth by 1-(m-t-butylacetamidophenyl)-3-methyl-3-methoxy urea

Swader¹,

Howe

1979

Weed sci.

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The experimental herbicide R-24191 [1-(m-t-butylacetamidophenyl)-3-methyl-3-methoxy urea] inhibited growth ofChlorella sorokinianaShihira and Kraus, O2evolution during CO2fixation byChlorellaand isolated leaf cells of spinach (Spinacia oleraceaL. ‘Winter Bloomsdale 769′), the photoreduction of NADP by isolated chloroplasts using water or hydroxylamine as the electron donor, the photoreduction of 2,6-dichloroindophenol by isolated chloroplasts, and O2uptake by isolated chloroplasts using paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) as the electron acceptor. The phenylurea herbicide had no effect on the last reaction when ascorbate plus 2,6-dichloroindophenol were used as the electron donor. The results indicate that the site of the phenylurea inhibition was in photosystem II between water-splitting and photosystem I.

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Section: Oxygraph Reactions Changes In O 2 Concentration Of the Reacsupporting

confidence: 89%

Section: Resultsmentioning

confidence: 99%

“…Cblorella cultures. Chlorella was cultured and the cells counted as reported previously (3,14). The initial cell concentration in the growth experiment was 1 x 10 4 cells mr 1 .…”

Section: Methodsmentioning

confidence: 99%

“…Chlorophyll determination. Chlorophyll was extracted from Chlorella cells with hot 80% ethanol (3,14,15). Chlorophyll was extracted from chloroplasts with 80% (v/v) acetone.…”

Section: Oxygraph Reactions Changes In O 2 Concentration Of the Reacmentioning

confidence: 99%

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Inhibition of Photosystem II andChlorellaGrowth by 1-(m-t-butylacetamidophenyl)-3-methyl-3-methoxy urea

Swader¹,

Howe

1979

Weed sci.

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“…The efficacy of the copper-diquat combinations in controlling aquatic plants is greater than that of either of the herbicides used singly [18-201. Diquat enhances the uptake of copper by hydrilla [2 11 and copper enhances the uptake of diquat [22,23]. In conducting laboratory toxicity tests, we used Cutrine-Plus, Komeen, diquat and combinations of these chelated copper formulations and diquat.…”

Section: Laboratory Toxicity Testsmentioning

confidence: 99%

Field and laboratory evaluation of the influence of copper-diquat on apple snails in Southern Florida

Winger

Imlay

McMillan

et al. 1984

Environmental Toxicology and Chemistry

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The recent decline of apple snail (Pomacea paludosa) populations in canals surrounding Loxahatchee National Wildlife Refuge in southern Florida coincided with the use of copper‐diquat for the control of the aquatic weed hydrilla (Hydrilla verticillata). Field and laboratory studies were designed to assess the effects of copper‐diquat on apple snails, which are the primary food of the endangered snail kite Rostrhamus sociabilis (formerly known as the Everglade kite). Acute toxicities (96‐h LC50 values) of Cutrine‐Plus and Komeen (chelated formulations of copper) to immature apple snails were 22 and 24 μg/L, respectively. Diquat was toxic at a concentration of 1,800 μg/L and did not increase the toxicity of copper when the chemicals were used in combination. Evaluation of field samples indicated that copper concentrations were higher in detritus than in water, plants and mud, and that there was a gradient of copper concentration from the canal to the interior, the highest residues being in samples from the canal. Copper associated with detritus (up to 150 μg/g) had no effect on growth or survival of apple snails in field cage and tank studies. Also, field applications of copper‐diquat to hydrilla had no effect on survival of caged adult and immature snails. Copper from field applications was rapidly taken out of solution by plants and organic material in the water and subsequently incorporated into the bottom detritus. Although the effects of repeated applications of copper‐diquat and high body burdens of copper (accumulated during exposure to herbicidal treatment) on survival and reproduction of apple snails are not known, the information available indicates that treatment of hydrilla with copper‐diquat was probably not responsible for the decline in the apple snail population. Application at recommended rates should pose no threat to these snails in the organically rich waters of southern Florida.

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Movements of Herbicides through Isolated American Pondweed (Potamogeton nodosus) Epidermal Tissues

Pringle

Anderson

1980

Weed sci.

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Enzymatically isolated American pondweed (Potamogeton nodosusPoir.) epidermal tissues were exposed to14C-labeled dichlobenil (2,6-dichlorobenzonitrile), diquat (6,7-dihydrodipyrido[1,2-α: 2′, 1′-c] pyrazinediium ion), silvex [2-(2,4,5-trichlorophenoxy) propionic acid] or 2,4-D [(2,4-dichlorophenoxy)acetic acid] at concentrations of 5 × 10−4, 5 × 10−5, and 5 × 10−610M, and the amount of herbicide crossing the tissue layer was measured. Rates of herbicide movement were compared to those found when copper sulfate pentahydrate was added as a potential synergist at concentrations of 5 × 10−5M (12.5 ppm), 5 × 10−6M (1.25 ppm), and 5 × 10−7M (0.125 ppm). Copper sulfate at 5 × 10−6M increased the rate of movement of all herbicides. However, diquat and dichlobenil exhibited the most enhanced movement in the presence of copper sulfate. Without copper sulfate, 0.1 nmoles of 5 × 10−6M14C diquat penetrated the tissue within 24 h, compared to 1.3 nmoles following the addition of 5 × 10−7M of copper sulfate.

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Diquat enhancement of cupric ion toxicity

Cited by 3 publications

References 22 publications

Inhibition of Photosystem II andChlorellaGrowth by 1-(m-t-butylacetamidophenyl)-3-methyl-3-methoxy urea

Inhibition of Photosystem II andChlorellaGrowth by 1-(m-t-butylacetamidophenyl)-3-methyl-3-methoxy urea

Field and laboratory evaluation of the influence of copper-diquat on apple snails in Southern Florida

Movements of Herbicides through Isolated American Pondweed (Potamogeton nodosus) Epidermal Tissues

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