Penetration, retention and transport of foliar applied single salts of Na, K, Rb and Cs

Abstract The penetration, retention and transport of foliar applied chloride salts of Na‐22, K‐43, Rb‐86, and Cs‐134 were studied under controlled environmental conditions. Penetration although occurring at different rates was found to be non‐selective and appears to be a passive free diffusion process. Retention in the treated area is similar for Na, K and Rb and greater for Cs. Transport of these elements away from that area and in the plant was greatest and fastest for Na and Rb and slower for Cs and K. Distribution in the plants following leaf treatment was similar for K, Rb and Cs but no significant upward transport was noted for Na. Losses from roots were greatest for Na. No significant K could be detected in the culture medium 4 days after treatment of the leaves.