Fluorometric Detection of Photosystem II Herbicide Penetration and Detoxification in Whole Leaves

Abstract

The applicability of fluorescence measurements for the detection of herbicide effects in whole leaves was analyzed. Based on the results known for isolated chloroplasts, normalized variable fluorescence of the initial rise was shown to be an appropriate tool for monitoring effects of photosystem II (PS II) herbicides. Equipment is described for monitoring the degree of inhibition by fluorescence induction measurements and microcomputer data analysis. The method is used to study the effect of pyrazon [5-amino-4-chloro-2-phenyl-3(2H)-pyridazinone], BAY DRW 1139 [4-amino-3-methyl-6-phenyl-1,2,4-triazin-5(4H)-one], and phenmedipham {3-[(methoxycarbonyl)amino] phenyl (3-methyl-phenyl)carbamate} after foliar application to different species. A rapid decrease of normalized variable fluorescence indicates penetration into leaf cells of all species tested. During a 5- to 7-day experiment, the apparent variable fluorescence decreased continuously in herbicide-susceptible plants, while it recovered in resistant plants due to an internal detoxification mechanism. The described method provides a rapid, simple, and nondestructive tool for analyzing the kinetics of penetration and detoxification of PS II herbicides in whole leaves.

Utilization of Chlorophyll Fluorescence Imaging Technology to Detect Plant Injury by Herbicides in Sugar Beet and Soybean

“…The F v / F m values of the treated plants were equal to those of the nontreated control plants (100%) at 3 to 6 DAT (Table 4). Similar results were reported by Voss et al (1984), Abbaspoor and Streibig (2007), and Roeb et al (2015). Herbicide stress in sugar beet was strongest 1 DAT with desmedipham plus phenmedipham plus ethofumesate plus lenacil in the cultivar ‘Capella’, with an F v / F m of only 34%.…”

THE PHOTOSYNTHETIC APPARATUS OF Acetabularia mediterranea GROWN UNDER RED OR BLUE LIGHT. BIOPHYSICAL QUANTIFICATION and CHARACTERIZATION OF PHOTOSYSTEM II and ITS CORE COMPONENTS

“…Transient light-induced changes of the relative fluorescence quantum yield were measured at room temperature with a setup analogous to that described by Voss et al (1984). Instead of the sample holder a cuvette with a translucent bottom was used and the fiber optics for the excitation and monitoring beams were mounted at the bottom face.…”

Studies on the protolytic reactions coupled with water cleavage in photosystem II membrane fragments from spinach

“…The redox state of acceptor component Q~ was determined by measuring fluorescence induction curves (Ikegami and Katoh 1973) with an equipment similar to that described by Voss et al (1984) except for a different sample holder for the cuvette. The redox potential was varied by changing the ratio of K 3 [Fe(CN)6]/K 4 [Fe(CN)6 ] and measured with a combined platinum-calomel electrode (Schott P65) and a Knick-pH-voltmeter.…”