14C Fixation and Translocation in two Clones of Sugarcane with Contrasting Rates of Sucrose Uptake in vitro

The rates of ¹⁴CO₂ fixation and translocation of ¹⁴C labelledassimilates were measured in field experiments at two timesof the day in two sugar-cane clones known to have differentrates of sucrose uptake in vitro but the same weight of leafper unit weight of cane. The rate of ¹⁴CO₂ fixation and the velocity and rate of translocationwere significantly greater at both times in the clone with thehigher rate of sucrose uptake in vitro. The velocities of translocationwere 2.18 and 2.36 cm/min^–1 for the clone with high sucroseuptake and 1.46 cm min^–1 at both times in the clone withlow uptake. It is suggested that among sugar-cane clones the ability oftheir canes to store sugar may play a part in determining theirrates of photosynthesis and translocation.