| | 1 | Author
| Angela Weber, Elke Fischer, Helmut Schipp Von Branitz, Ulrich Lüttge | Requires cookie* | | | Title
| The Effects of the Herbicide Sethoxydim on Transport Processes in Sensitive and Tolerant Grass Species I. Effects on the Electrical Membrane Potential and Alanine Uptake  | | | | Abstract
| Sethoxydim is a postemergence herbicide used to control grass weeds. Application at concen-trations higher than 0.1 mM to leaf segments of the sensitive grass species Poa pratensis and Festuca ovina and the tolerant species Poa annua and Festuca rubra, caused a reduction of the electrical membrane potential (AE). The depolarization was reversible and depended linearly on the herbicide concentration. The passive diffusion component of AE was not affected by sethoxy-dim indicating that the herbicide did not change passive permeability characteristics of the plas-malemma. Consequently sethoxydim reduced the active component of AE that depended on primary active transport processes across the plasmalemma. Moreover, sethoxydim increased the reduction of AE of grass leaf cells that was associated with the onset of H + -amino acid cotrans-port. Simultaneously the uptake of alanine into leaf segments was reduced. From these results it had to be concluded that the plasmalemma-bound H + -ATPase was inhibited by sethoxydim in sensitive and tolerant grasses. In vitro ATP hydrolysis of plasmalemma vesicles isolated from grass leaves by polymer phase partitioning, however, was not inhibited by sethoxydim. Apparent-ly another primary active transport mechanism that may contribute to an electrochemical H + -gradient across the plasmalemma, i.e. a plasmalemma-bound redox system, should be the site of inhibition responsible for the membrane effects of sethoxydim observed in vivo. | | | |
Reference
| Z. Naturforsch. 43c, 249—256 (1988); received December 23 1987 | | | |
Published
| 1988 | | | |
Keywords
| Plasmalemma, Membrane ATPase, Herbicide, Sethoxydim, Amino Acid Uptake | | | |
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| default:Reihe_C/43/ZNC-1988-43c-0249.pdf | | | | Identifier
| ZNC-1988-43c-0249 | | | | Volume
| 43 | |
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