Variation in the Rate of Cell Division in the Apical Meristem of Sinapis alba During Transition to Flowering

Rates of cell division in the central and the peripheral zonesof vegetative and evoked meristems of Sinapis alba have beenmeasured by accumulation of metaphases after colchicine treatment.The cells of the central zone had a longer cycle than the cellson the flanks of both kinds of meristems. The duration of thecell cycle was shortened in both zones of the meristem duringtransition to flowering. It was shown that the mitotic indicesof the two regions of the meristem were closely comparable totheir rates of cell division and therefore could be consideredrepresentative of the rates of cell division.