| Autor: |
Erdei, László, Oláh, Zoltán, Bérezi, Alajos |
| Předmět: |
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| Zdroj: |
Physiologia Plantarum; Jan1984, Vol. 60 Issue 1, p81-85, 5p |
| Abstrakt: |
Potassium uptake and release in roots and translocation to the shoots were studied in 14-day-old winter wheat (Triticum aestivum L. cv. Martonvásári 8 ) of different K status. Transport processes were measured in the growth solution for 5 h ensuring near-equilibrium conditions. The uptake showed three phases: (1) at low external K+ concentration it increased with increasing concentration and culminated at 0.1 mM;(2) between 0.1 and 1 mM it decreased and (3) it increased again above 1 mM. The release of K+ showed a constant low level below 1 mM while paralleling the uptake above that. The uncoupler 2,4-dinitrophenol inhibited uptake phases (1) and (2) , whereas it did not affect either phase (3) or K+ release. Translocation showed similar patterns. It is concluded that phases (1) and 2 depend on metabolic energy while phase (3) is mostly passive. It is emphasized that different types of regulation seem to operate in the transport mechanism: i.e. limitation by transport sites control by negative feedback and by K+/K + exchange, respectively. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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