Ion Absorption by Shoot Tissue: Kinetics of Potassium and Rubidium Absorption by Corn Leaf Tissue.

The relative impermeability of the surfaces of leaves to water and mineral ions in solution is a condition upon which the life of terrestrial higher plants depends. However, for the investigator this feature imposes difficulties on attempts to make quantitative studies of the process of ion absorption by leaf tissue. The importance of this absorption process in the physiology of leaf cells has recently been discussed, and a technique has been described for experiments on ion absorption by excised leaf tissue (6). As demonstrated there, this technique avoids passage of the ions through the epidermis as a rate-limiting step in the absorption process, by exposing the mesophyll cells directly to the solution from which absorption takes place. This method has now been used in the experiments described here. These experiments deal with the absorption of potassium and rubidium by excised leaf tissue of corn.