Further analysis of the moving strand model of translocation, using a numerical calculation

Abstract

Numerical computer results for the moving strand model of phloem translocation are in excellent agreement with the analytical results of Canny and Phillips. Numerical results are presented for the case of constant loading of radioactive sugar, for which Canny and Phillips failed to specify the appropriate boundary condition. Numerical results are obtained for a pulse time variation of loading and for a pulse time variation of sugar in the loading region reservoir, cases which were not solved by Canny and Phillips, and the results are compared with experimental data. We show that the moving strand model does not predict the kind of moving pulse of tracer observed in morning glory (Fisher 1975) after pulse labeling a source leaf with 14CO2 except when transport parameters are specified that clearly conflict with those measured and proposed by Canny. We see little theoretical justification for retaining the moving strand model.