Potassium Absorption by Rice at Different Levels of Organization

Abstract

Abstract A study was made of the effects of temperature and calcium on the properties of K + transport in rice roots ( Oryza sativa L. cv. Dunghan Shali), in cell suspension culture of rice and in callus cultures. The rates of influx and efflux of K + were measured by using 86 Rb as tracer, and the net change in K + content was determined by atomic absorption spectrophotometry. In roots of low salt status the K + transport mechanism exhibits a positive temperature dependence and calcium exerts a stimulation. In cell and callus cultures a transport mechanism of this kind is lacking, and the K + fluxes are inhibited by calcium and independent of temperature. Chilling‐induced K + leakage is similar for both types of tissue, and can be characterized by a negative temperature‐coefficient and the inhibitory effect of calcium.