Transportprozesse in Vallisneria-Blättern und die Wirkung von Kinetin und Kolchizin: I. Aufnahme von α-Aminoisobuttersäure in Gewebe von Vallisneria und die Wirkung von Kinetin

Abstract

Summary The uptake of α-aminoisobutyric acid (AIB)—a metabolically inert amino acid—into the leaf tissue of Vallisneria spiralis L. was studied. These are the main results: 1. The uptake proceeds proportional with time over a period of 100 hours from a 1 mM AIB solution reaching an accumulation ratio of about 5 during this period. The time proportional uptake phase continues for 24 hours from a 20 mM solution. 2. The concentration dependence of the uptake shows saturation kinetics with half saturation at 1 mM. 3. The efflux of the amino acid is very low and can be neglected at a first approximation in the· uptake experiments. 4. Kinetin (1 μ M) shows typical effects on uptake and leakage. After the kinetin effect has developed, the uptake of amino acid from a 1 mM AlB solution proceeds with a higher rate but a constant velocity during a period of 100 hours. 5. The capacity for amino acid accumulation is enhanced under the influence of kinetin. 6. The maximal velocity of uptake (V max ) reached at saturating concentrations is increased by kinetin. 7. The leakage rate is reduced by kinetin, however, this effect does not explain the higher uptake rate and accumulation ratio.