Role of Assimilate Translocation and Carbohydrate Accumulation in Fruit Set of Strawberry

Soluble sugar and starch levels and translocation of 14 C-Iabeled photoassimilates in receptacles of pollinated, nonpollinated, and auxin-treated strawberry flowers ( Fragaria × ananassa Duch. ‘Fern’) were examined from 0 to 144 hr after anthesis and correlated with fruit set and initial growth. Receptacle dry weight of nonpollinated flowers increased very little during the experimental period, whereas receptacles of pollinated and auxin-treated flowers showed a gain in dry weight within 24 hr, which continued throughout the experimental period. However, 14 C accumulation in flower receptacles did not reflect the initial differences in growth, indicating that recently fixed 14 C-labeled photosynthate was not the source for the observed dry weight increases. Analysis of carbohydrate pool sizes in treated receptacles indicated no consistent correlation between pool sizes and fruit set and initial growth. Thus, fruit set and initial growth in strawberry is not limited by the capacity of receptacles either to mobilize current source leaf assimilates or accumulate carbohydrates.