ZfN: Search Results

1	Author	H. Artm, K. L. Ichtenthaler	Requires cookie*
	Title	Chloroplast Biogenesis, Its Inhibition and Modification by New Herbicide Compounds
	Abstract	Biogenesis and developm ent o f chloroplasts are sum m arized in the light o f new findings; the interactions o f different groups o f photosynthetic herbicides with chloroplast developm ent are indicated. The effect o f two new active ingredients, m evin olin* and sethoxydim **, on chloroplast m odification and biogenesis are described. M evinolin blocks the cytoplasm ic HMG-CoA reductase and sterol accum ulation and m odifies chloroplast differentiation via the formation o f a sun-type chloroplast. Sethoxydim inhibits leaf growth in grasses and gram ineous crop plants and strongly affects chloroplast biogenesis and differentiation at all stages o f development from proplastids via prochloroplasts to young and mature chloroplasts. This applies to thylakoid formation and m ultiplication, grana form ation as well as chloroplast division and chlorophyll and carotenoid accumulation. The chlorophyll fluorescence induction kinetics (Kautsky effect) indicate that photosynthesis is not affected. At higher doses sethoxydim stops all growth responses o f maize plants and induces the accum ulation o f anthocyanins.
	Reference	Z. Naturforsch. 39c, 492 (1984); received N ovem ber 29 1983
	Published	1984
	Keywords	Chloroplast Biogenesis, Herbicide Action, M evinolin, Prochloroplast, Sethoxydim
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	TEI-XML for	default:Reihe_C/39/ZNC-1984-39c-0492.pdf
	Identifier	ZNC-1984-39c-0492
	Volume	39

2	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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	TEI-XML for	default:Reihe_C/43/ZNC-1988-43c-0249.pdf
	Identifier	ZNC-1988-43c-0249
	Volume	43

3	Author	Angela Weber, Ulrich Lüttge	Requires cookie*
	Title	The Effects of the Herbicide Sethoxydim on Transport Processes in Sensitive and Tolerant Grass Species II. Effects on Membrane-Bound Redox Systems in Plant Cells
	Abstract	Leaf slices of sethoxydim-sensitive (Poa pratensis, Festuca ovina) and tolerant (Poa annua, Festuca rubra) grass species were found to be able to reduce extracellular ferricyanide by electron transport across the plasmalemma. This reduction was inhibited by the herbicide sethoxydim, and the sensitive species were much more strongly affected than the tolerant ones. The inhibition was concentration dependent. Sethoxydim affected the electron transport in isolated Poo chloroplasts. Polarographic and photometric measurements of ferricyanide reduction suggested photosystem II to be the site of action. Inhibition occurred only in the sensitive species Poa pratensis and was linearly dependent on concentration. In isolated mitochondria from sensitive Zea mays coleop-tiles sethoxydim also acted as an inhibitor of electron transport. Only slight inhibition was meas-ured with mitochondria from tubers of tolerant potato (Solanum tuberosum). It is concluded that sethoxydim generally acts as inhibitor of membrane-bound redox systems. The specific inhibition of the plasmalemma-bound redox system of sethoxydim-sensitive plants could contribute to a selective action of the herbicide.
	Reference	Z. Naturforsch. 43c, 257—263 (1988); received December 23 1987
	Published	1988
	Keywords	Sethoxydim, Herbicide, Redox Systems, Isolated Organelles, Plasmalemma
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	TEI-XML for	default:Reihe_C/43/ZNC-1988-43c-0257.pdf
	Identifier	ZNC-1988-43c-0257
	Volume	43

4	Author	I. Struve, B. Golle, U. Lüttge	Requires cookie*
	Title	Sethoxydim-Uptake by Leaf Slices of Sethoxydim Resistant and Sensitive Grasses
	Abstract	Leaf slices o f the sethoxydim sensitive grasses Poa pratensis and Festuca ovina and the sethoxy dim resistant grasses Poa annua and Festuca rubra take up the herbicide at similar rates. U ptake is alm ost linear with concentration up to 2 m M , independent o f light and little affected by tem pera ture betw een 0 and 25 °C. U ptake is highly pH sensitive. A t pH 7.0 rates o f uptake are only about 20% o f the rates observed at pH 3.5. Tim e course o f uptake suggests a rapid equilibration o f the com partm ents taking up the herbicide within 2 h. It is suggested that sethoxydim uptake by the grass-leaf tissue is a nonspecific process involving passive lipid diffusion and lipid equilibration of the non-dissociated weak acid sethoxydim (pK a = 4 .6).
	Reference	Z. Naturforsch. 42c, 279 (1987); received August 6/N ovem ber 24 1986
	Published	1987
	Keywords	Sethoxydim, H erbicide, Lipid D iffusion, Poa annua, P oa pratensis
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	TEI-XML for	default:Reihe_C/42/ZNC-1987-42c-0279.pdf
	Identifier	ZNC-1987-42c-0279
	Volume	42