Partial floral evocation by exogenous cytokinin in the long‐day plant Sinapis alba

A single application of benzyladenine (BA) at 4.3 × 10−5M to the shoot apex of vegetative plants of Sinapis alba L. causes an increase of the import of [14C]‐assimilates in the apical bud and of the starch content. BA also produces the breakdown of the vacuoles into smaller vacuolar units and an increase of the mitotic index leading to nearsynchronization of the meristem cell population in G1. All these changes normally occur in the meristem of Sinapis plants during the transition to flowering (full evocation). Other events normally associated with full evocation are not caused by BA which thus produces only partial evocation. The part of evocation produced by BA is different from that caused by high irradiance.