Effect of tentoxin on K+transport in winter wheat seedlings of different K+-status |
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Authors: | Martin G Klotz László Erdei |
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Institution: | Dept of Biophysics, Section of Biology, Friedrich Schiller Univ. of Jena, GDR-6900 Jena;Inst. of Biophysics. Biological Research Center, Hungarian Academy of Sciences P. O. B. 521, H-6701 Szeged, Hungary. |
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Abstract: | Klotz, M. G. and Erdei, L. 1988. Effect of tentoxin on K+ transport in winter wheat seedlings of different K+-status. The influence of the phytoeffective mycotoxin, tentoxin, cyclo-(L-leucyl-N-methyltrans-dehydronhenyl-alanyl-glycyl-N-methyl-L-alanyl)] (in K+ uptake and on translocation of K+ from roots to shoot was studied in 14-day-old winter wheat plants (Triticum aestivum L. cv. Martonvásári-8) grown at different levels of K+ supply. For comparison, the effects of 2,4-dinilrophcnol and valinomycin were also investigated. In I-h experiments I pM tentoxin reduced K+ influx in the routs over the external K+ concentration range 0.1 to 1 mM (low-K+ plants), whereas stimulation was observed al lower and higher K+ concentrations. On the other hand, in plants grown at 0.3 mM K+, tentoxin stimulated the translocation of K+ from roots to shoots in 5-h experiments. Valinomycin affected K+ transport only al high K+-status (slight stimulation). In low-K+ plants 2,4-dinitrophenol (DNP) caused drastic inhibition of K+ uptake, but in high-K+ plants uptake was only slightly inhibited and translocation slightly stimulated, It is concluded that the opposite effects of tentoxin on K+ uptake and translocation agree1 with the directions of the H+-ATPases pumping H+ towards the apoplast and located at the cortex plasmalemma and the xylem parenchyma plasma-membrane, respectively. These effects should probably be attributed to the interaction between tentoxin and the K+-carrier protein rather than to a direct influence of tentoxin on H+-ATPase. |
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Keywords: | 2 4-Dinilrophcnol ion uptake potassium uptake tentoxin translocation Triticum aestivum valinomycin wheat |
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