Nature and magnitude of calcium uptake by excised roots of Vetch and Barley

Summary Generally, Ca uptakes were higher and K uptakes lower for excised vetch roots as opposed to those of barley under similar conditions. This behavior was considered to be related to root ion exchange properties and Dorman theory, since the ion exchange capacity of vetch roots is considerably higher than that of barley. Metabolic inhibitors were very effective against K uptakes in contrast to Ca uptakes by both vetch and barley indicating that Ca uptake was primarily non-metabolic under these experimental conditions. The rapidity with which most of the Ca previously taken up was removed by a Ba solution suggests that, for short time periods, a quasi-reversible ion exchange relationship existed between Ba and Ca. Fundamental differences between Ca and K washout curves are attributed to this primarily non-metabolic process. It was concluded that uptake of Ca by excised vetch and barley roots is basically of a surface nature.Senior author currently Assistant Plant Physiologist at the Connecticut Agricultural Experiment Station, New Haven, CT, 06504.