Uptake of Carrier-free 137Cs by Ramalina reticulata

Abstract

The uptake of carrier-free ¹³⁷Cs by Ramalina reticulata Kremp. does not appear to be directly linked to metabolism. The results indicate the presence of a barrier to entry of ¹³⁷Cs. The barrier is stabilized by Ca ions. Removal of Ca by pretreatment of the tissue in monovalent salt solutions increases the uptake of ¹³⁷Cs. Uptake under anaerobiosis is also greater than normal, but in this case, Ca displaced from the barrier membrane is not lost from the tissue and normal permeability is rapidly re-established when aerobic conditions are restored. Under anaerobiosis Ca²⁺ increases damage to the respiratory mechanism presumably by increasing retention of toxic products.