Chlorophyll fluorescence evaluation of agrochemical interactions with propanil on propanil-resistant barnyardgrass (Echinochloa crus-galli)

Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Ronald E. Talbert ◽  
Robert E. Hoagland
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Synergistic Effects ◽  
Laboratory Studies ◽  
Photosynthetic Inhibition ◽  
Fluorescence Measurements ◽  
Transport Inhibition ◽  
Leaf Segments

Resistance to propanil by a barnyardgrass (BYG) biotype has been reported, and its occurrence is becoming widespread in U.S. rice-producing regions. Interactions between propanil and the herbicides anilofos, molinate, pendimethalin, piperophos, quinclorac, and thiobencarb and the insecticide carbaryl were evaluated in laboratory studies for improved control of propanil-resistant barnyardgrass (R-BYG). Chlorophyll fluorescence measurements of BYG leaf segments were used to ascertain electron transport inhibition and to assess the synergy/antagonism of propanil (100 μM) with the various additives (50 μM). Synergistic effects on photosynthetic inhibition were found with anilofos, carbaryl, pendimethalin, and piperophos in combination with propanil. Such synergistic actions of chemicals with propanil may lead to chemical combinations useful for R-BYG control.

Quantitative Mapping of Leaf Photosynthesis Using Chlorophyll Fluorescence Imaging

1995 ◽  
Vol 22 (2) ◽  
pp. 277 ◽  
Author(s):  
B Genty ◽  
S Meyer
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Quantum Yield ◽  
Co2 Assimilation ◽  
Linear Electron ◽  
Leaf Photosynthesis ◽  
Heterogeneous Distribution ◽  
Fluorescence Measurements ◽  
Wide Range ◽  
Photochemical Yield

A method has been developed for routine, non-invasive monitoring of the topography of leaf photochemistry. The method uses video images of leaf chlorophyll fluorescence, taken during steady-state photosynthesis and during a transitory saturation of photochemistry, to construct, pixel by pixel, an image of the photochemical yield of photosystem II (PSII). The photochemical yield of PSII was estimated according to Genty et al. (1989) (Biochimica et Biophysica Acta 990, 87-92). The effectiveness of the method was shown by mapping the heterogeneous distribution of photosynthetic activity after treatment with either a herbicide (DCMU), abscisic acid, or during the course of the induction of photosynthesis. Leaf CO2 assimilation was simultaneously monitored under non- photorespiratory conditions to estimate the average quantum yield of linear electron transport. A unique proportional relationship was found between the mean photochemical yield of PSII calculated from images of the photochemical yield of PSII, and the average quantum yield of linear electron transport in three plant species exposed to a wide range of treatments or conditions. This new ability to quantitatively visualise leaf photochemistry provides a powerful tool to probe the spatial distribution of leaf photosynthesis. Possible errors in estimating the photochemical yield of PSII from mean fluorescence measurements are discussed.

Decreased photosynthetic efficiency in plant species exposed to multiple airborne pollutants along the Russian-Norwegian border

2000 ◽  
Vol 78 (8) ◽  
pp. 1021-1033 ◽  
Author(s):  
Ann Marie Odasz-Albrigtsen ◽  
Hans Tømmervik ◽  
Patrick Murphy
Keyword(s):  
Chlorophyll Fluorescence ◽  
Plant Species ◽  
Photosynthetic Efficiency ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Plant Cover ◽  
Mixed Forest ◽  
Airborne Pollutants ◽  
Fluorescence Measurements ◽  
Study Sites

Photosynthetic efficiency was estimated by chlorophyll fluorescence measurements (Fv/Fm) in 11 plant species growing along a steep gradient of airborne pollution along the Russian-Norwegian border (70°N, 30°E). Photosynthetic efficiency was positively correlated with environmental variables including annual temperature and a maritime gradient and was negatively correlated with the airborne concentrations of Cu, Ni, and SO2 from the Cu-Ni smelters. Photosynthetic efficiency in six plant species from the mixed forest, but not pine (Pinus sylvestris L.), and three species from the birch forest was inversely correlated with SO2 and the concentrations of Ni and Cu in lichens. Measurement of fluorescence in these species was a sensitive indicator of pollutant impact. Plant cover at the 16 study sites and the photosynthetic efficiency of five target species correlated with normalized difference vegetation index (NDVI) values. This study demonstrated that it is possible to detect relations among field-measured ecophysiological responses in plants, levels of airborne pollutants, and satellite remote-sensed data.Key words: chlorophyll fluorescence, smelters, sulfur dioxide, nickel, copper, normalized difference vegetation index (NDVI).

scholarly journals The function of D1-H332 in Photosystem II electron transport studied by thermoluminescence and chlorophyll fluorescence in site-directed mutants of Synechocystis 6803

2004 ◽  
Vol 271 (17) ◽  
pp. 3523-3532 ◽  
Author(s):  
Yagut Allahverdiyeva ◽  
Zsuzsanna Deák ◽  
András Szilárd ◽  
Bruce A. Diner ◽  
Peter J. Nixon ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Photosystem Ii ◽  
Synechocystis 6803

Resistance to chlortoluron in a downy brome (Bromus tectorum) biotype

Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 237-245 ◽  
Author(s):  
Julio Menendez ◽  
Fernando Bastida ◽  
Rafael de Prado
Keyword(s):  
Electron Transport ◽  
Photosynthetic Electron Transport ◽  
Fold Increase ◽  
Downy Brome ◽  
Fresh Weight ◽  
Wheat Field ◽  
P450 Monooxygenases ◽  
Fluorescence Measurements ◽  
Higher Ed ◽  
Herbicide Metabolism

A downy brome population in a winter wheat field at Córdoba, Spain, survived use rates of chlortoluron (2.5 to 3.5 kg ai ha−1) over 2 consecutive yr, where wheat monoculture and multiple annual chlortoluron applications had been carried out. The resistant (CR) biotype showed a higher ED50value (7.4 kg ai ha−1; the concentration required for 50% reduction of fresh weight) than the susceptible (S) control (2.2 kg ai ha−1), with a 3.4-fold increase in chlortoluron tolerance. Chlortoluron resistance in the CR downy brome biotype was not caused by altered absorption, translocation, or modification of the herbicide target site but by enhanced detoxification. The inhibition of both the recovery of photosynthetic electron transport and chlortoluron metabolism in the CR biotype due to the presence of the Cyt P450 inhibitor 1-aminobenzotriazole (ABT) indicates that herbicide metabolism catalyzed by Cyt P450 monooxygenases is related to chlortoluron resistance in CR plants. Although both biotypes degraded chlortoluron byN-dealkylation and ring-methyl hydroxylation and seem to share the same ability to form polar conjugates, degradation in the resistant biotype is more efficacious as this biotype metabolizes the parent herbicide faster and to a greater extent than its susceptible counterpart. The ability of the susceptible biotype to ring-hydroxylate chlortoluron, albeit at much slower rate, probably explains its moderate tolerance to chlortoluron observed in the growth assays and its minor photosynthetic electron transport recovery observed in fluorescence measurements.

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