14C fixation and translocation in two clones of sugar-cane with contrasting rates of sucrose uptake in vitro

The rates of 14CO2 fixation and translocation of 14C labelled assimilates were measured in field experiments at two times of the day in two sugar-cane clones known to have different rates of sucrose uptake in vitro but the same weight of leaf per unit weight of cane. The rate of 14CO2 fixation and the velocity and rate of translocation were significantly greater at both times in the clone with the higher rate of sucrose uptake in vitro. The velocities of translocation were 2.18 and 2.36 cm/min-1 for the clone with high sucrose uptake and 1.46 cm min-1 at both times in the clone with low uptake. It is suggested that among sugar-cane clones the ability of their canes to store sugar may play a part in determining their rates of photosynthesis and translocation. (author)