Export of 14C- and 11C-labelled assimilate from wheat and maize leaves: effects of parachloromercurobenzylsulphonic acid and fusicoccin and of potassium deficiency

Abstract

Tracer exported from wheat and maize leaves after photosynthetic fixation was resolved into theoretical pools by mathematical analysis of the rate of loss of either 14C or 11C from the leaf. Fusicoccin, known to stimulate the proton–sucrose symport, had no effect on the rate constants of exchange between pools or loading into the translocation stream of normal plants. K+-deficient plants showed an increased transfer of C into the storage pool when treated with fusicoccin. Parachloromercurobenzylsulphonic acid known to inhibit export not only reduced the rate constant for export but also increased the exchange from the export pool to the storage pool.