Depth of dormancy in tomato (Lycopersicon esculentum Mill.) seeds is related to the progression of the cell cycle prior to the induction of dormancy

Cell cycle activities are initiated following imbibition of non-dormant see ds. However, it is not known whether cell cycle related events other than D NA replication also remain suppressed in imbibed dormant seeds. The objecti ve of this study was to demonstrate that the transitions between the non-do rmant and dormant (both primary and secondary) states are reflected in cell cycle events, such as DNA replication and the changing patterns of the mic rotubular cytoskeleton involved in the processes of growth and development. The present studies were conducted on seeds from tomato (Lycopersicon escu lentum cv. Moneymaker) that possessed primary dormancy or were manipulated to attain secondary dormancy. In addition, a non-dormant abscisic acid (ABA )-deficient mutant, sit(w), was used. DNA replication, as measured by flow cytometry, acid beta -tubulin accumulation, analysed by immunoblotting, wer e compared with immunocytological studies of active DNA synthesis and micro tubular cytoskeleton formation. It is shown that the depth of dormancy, whi ch distinguishes primary and secondary dormancy, may depend on the progress ion of the cell cycle prior to the induction of dormancy.