Effect of Substituted Uracil Herbicides on Photosynthesis

Hoffmann, C. E.; McGahen, J. W.; Sweetser, Philip B.

doi:10.1038/202577a0

Cited by 23 publications

(9 citation statements)

References 7 publications

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“…The inhibition by DCMU would eliminate light-driven nitrogenase activity by epiphytic cyanobacteria and would probably reduce algal excretion products which might serve as energy sources for the heterotrophic diazotrophs. The AR activity which remained after treatment with DCMU was possibly due to diazotrophic members of the Rhodospirillaceae in the epiphytic microbial community since they are reported to be relatively insensitive to DCMU (7). It may also have been due in part to the heterotrophic population utilizing carbon substrates leaked by the duckweed plants and in part to "dark" heterotrophic N2 fixation by cyanobacteria.…”

Section: Discussionmentioning

confidence: 98%

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Nitrogen Fixation (Acetylene Reduction) Associated with Duckweed ( Lemnaceae ) Mats

Zuberer

1982

Appl Environ Microbiol

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Duckweed (Lemnaceae) mats in Texas and Florida were investigated, using the acetylene reduction assay, to determine whether nitrogen fixation occurred in these floating aquatic macrophyte communities. N2-fixing microorganisms were enumerated by plating or most-probable-number techniques, using appropriate Nfree media. Results of the investigations indicated that substantial N2-fixation (C2H2) was associated with duckweed mats in Texas and Florida. Acetylene reduction values ranged from 1 to 18 ,umol of C2H4 g (dry weight)-' day-' for samples incubated aerobically in light. Dark N2 fixation was always twoto fivefold lower. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (7 to 10 ,uM) reduced acetylene reduction to levels intermediate between light and dark incubation. Acetylene reduction was generally greatest for samples incubated anaerobically in the light. It was estimated that 15 to 20% of the N requirement of the duckweed could be supplied through biological nitrogen fixation. N2-fixing heterotrophic bacteria (10' cells g [wet weight]-' and cyanobacteria (105 propagules g [wet weight]-1 were associated with the duckweed mats. Azotobacter sp. was not detected in these investigations. One diazotrophic isolate was classified as Klebsiella.

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Section: Discussionmentioning

confidence: 98%

“…These mats may range from a few millimeters to several centimeters in thickness, and substantial biomass production is associated with the mats. Productivity values as high as 7,100 kg ha-' year-' have been reported (6).…”

mentioning

confidence: 99%

Nitrogen Fixation (Acetylene Reduction) Associated with Duckweed ( Lemnaceae ) Mats

Zuberer

1982

Appl Environ Microbiol

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“…In agreement with previous findings (2), direct application of isocil to the bud faile(d to inhibit flowering. It is conclu(led that isocil, in contrast to 6-AU, prevents flowering through its potent and specific anitiplhotosynthetic activity (6,7). Neither comlpoundI can be considered to block floxwerilng specifically.…”

Section: Resultsmentioning

confidence: 99%

Bioassay of Floral Stimulus in Xanthium

Searle

1965

Plant Physiol.

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“…Bromacil is a powerful and selective inhibitor of photosynthesis (Hilton et al 1964;Hoffman et al 1964;Hoffman 1971). It inhibits photosynthesis in vascular plants, algae and blue-green bacteria by blocking a step in the electron transport chain of photosystem II (Scott 1987).…”

Section: Bromacilmentioning

confidence: 99%