EXPERIMENTALLY DETERMINED TRANSLOCATION OF CS-134 IN POTATOES - COMPARISON WITH THE RADIOECOLOGICAL MODEL ECOSYS-87 AND LITERATURE DATA

The results of a greenhouse experiment on the translocation rate of Cs -134 from potato leaves to tubers were compared with calculations of t he radioecological model ECOSYS-87 and other literature values. The Cs activities applied at three development stages (three pinnate leaves fully developed, onset of flowering, onset of yellowing) to leaves of the plant were taken as starting points for the model to calculate the activity in the tubers at harvest. The default yield in the model was replaced by the experimentally obtained values. The translocation rat e measured in the greenhouse experiment was 4 to 14 times higher than the calculations of the model. Some possible reasons for such a high t ranslocation rate, compared with the literature data, are discussed. B ased on these comparisons, it is concluded that maximal translocation occurs at the growth stage of flowering of a crop and that the develop ment stage of a crop might be a stronger parameter to describe the tim e dependency of translocation than the usually applied parameter 'days before harvest'.