The role of cis-abscisic acid (ABA) and gibberellins (GAs) in the induction of cell-cycle activities has been studied during imbibition and subsequent germination of tomato seeds. Using flow cytometry, nuclear replication activity was investigated in embryo root tips isolated from seeds of the ABA-deficient mutant sit(w), the GA-deficient mutant gib-1, and the wild-type (MM) tomato (Lycopersicon esculentum Mill, cv. Moneymaker) upon imbibition in water, 10 mu M GA(4+7), 5 mu M ABA or 5 mu M ABA + 10 mu M GA(4+7). The nuclei of fully matured dry MM, sit(w) and gib-1 seeds predominantly showed 2...
