Dry Matter Distribution Between the Shoot and Storage Root of Carrot (Daucus carota L.)

The effects of foliar sprays of gibberellic acid (GA) on dry matter distribution in carrots were investigated in three field experiments between 1977 and 1979. The results were interpreted by using a simple quantitative model of assimilate partitioning between storage root and shoot. Although the response to GA varied depending on the year in which the experiment was done, the model successfully described the effects of spraying time, GA concentration, planting density, plant age and cultivar. The maximum effects on repartitioning were achieved with concentrations of 100–500 mg 1−1 GA and, except for very early or late sprays, the effect was constant with time over a roughly 4-week period. The multiplicative nature of the model was useful in that despite the occurrence of various interactions, a similar assimilate partitioning response to GA in all four cultivars was demonstrated. The model did not suggest an explanation for the seasonal effects.