Abscisic Acid Facilitates Sucrose Import by Strawberry Fruit Explants and Cortex Disks in Vitro

Abstract

Strawberry (Fragaria × ananassa Duch. cv. Tristar) fruit explants and tissue disks were used for short term in vitro studies of [14C] sucrose import. An aqueous feeding solution of 50 mm Mes, 10 mm CaCl2, 10 mm EDTA, and 600 mm [14C] sucrose at pH 5.5 resulted in maximum accumulation of sucrose by fruit expiants during 2 hr. Young fruit exhibit the highest sink activity (sucrose imported per mg fruit dry weight), a value that declined as fruit aged. Sink strength (total sucrose accumulated per fruit) was positively correlated to fruit dry weight at 13 to 15 days after pollination. Inclusion of abscisic acid (ABA) in the incubation solution of fruit expiants and cortex disks increased sucrose accumulation 45% and 37%, respectively, above control values.