Adaptation of barley roots to low oxygen supply and its relation to potassium and sodium uptake.

The uptake of Na(+) and K(+) by barley seedlings grown on aerated or non-aerated solutions was studied. Plants growing in culture solution took up K(+) with high selectivity whether the solution was aerated or not. Roots of plants grown on aerated CaSO(4) and transferred to a solution of KCl and NaCl had a lower preference for K(+) than roots of plants grown on non-aerated CaSO(4). Both kinds of low-salt roots were much less able to discriminate between K(+) and Na(+) than high-salt roots grown on a culture solution. The different levels of K(+) selectivity are suggested to be related to H(+) release from the tissue.