Influence of fusicoccin and xylem wall adsorption on cation transport into maturing wheat (Triticum aestivum) ears

Detached wheat ears with 18 cm stem were incubated for 3 days standing in 2 mM RbCl + 2 mM SrCl2. Strontium was mainly translocated with the transpiration stream to the glumes while rubidium, similar to K, accumulated in the lower part of the stem. The selective elimination of Rb from the xylem was stimulated by fusicoccin. Our result suggest that the rapid transfer from the xylem to surrounding cells was driven by a membrane potential difference.