Experimentally determined translocation of 134Cs in potatoes. Comparison with the radioecological model ECOSYS-87 and...

The results of a greenhouse experiment on the translocation rate of 134Cs from potato leaves to tubers were compared with calculations of the radioecological model ECOSYS-87 and other literature values. The 134Cs 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 rate measured in the greenhouse experiment was 4 to 14 times higher than the calculations of the model. Some possible reasons for such a high translocation rate, compared with the literature data, are discussed. Based on these comparisons, it is concluded that maximal translocation occurs at the growth stage of flowering of a crop and that the development stage of a crop might be a stronger parameter to describe the time dependency of translocation than the usually applied parameter 'days before harvest'.