The flowering is the crucial moment in plant life cycle demanding the compiling of the shoot apical meristem from leave to flower formation. The whole mechanism of the day-neutral plants flowering onset still not have been known.
Tobacco plants transformed with cdc25 gene from S. pombe flowered dramatically earlier (among others characteristics e.g. smaller root system). Grafting experiments and anatomical study showed that the shoot apical meristem was preferentially influenced in the onset to flowering in Spcdc25 tobacco plants.