Effect of brassinosteroid on cell division and enlargement in cultured carrot (Daucus carota L.) cells

When added at 3.10^–6 mM to auxin-starved suspension cultured carrot (Daucus carota L.) cells, the steroid hormone 24-epibrassinolide (BR) induces cell enlargement but not cell division.This is at variance from the effect of 2,4-D which, in the same experimental conditions, restores cell division without having any effect on cell enlargement.Furthermore, in the tested experimental conditions, the effect of BR is dominant over the effect of 2,4-D when the two hormones are simultaneously supplied to the auxin-starved culture.Abbreviations BR brassinosteroid, 24-epibrassinolide - 2,4-D 2,4-dichlorophenoxyacetic acid - IAA indole-3-acetic acid - GA₃ gibberellic acid