UPTAKE AND TRANSLOCATION OF CALCIUM IN CUCUMBER

Uptake and translocation of Ca2+ (45Ca) were compared with water translocation in 12 day old intact plants and excised roots of cucumber (C. sativus L. cv. Cilla), which had been cultivated in nutrient solution. No immediate reduction of Ca2+ uptake occurred when water translocation was reduced by excision of the shoot. In the presence of 2,4-dinitrophenol [DNP], Ca2+ translocation was reduced in the intact plants while water translocation was unchanged. Evidently regulation of Ca2+ uptake is primarily achieved in the root. The DNP-sensitive mechanism of Ca2+ uptake was associated with the root and probably represented transport through the endoderms into the stele.