[Alteration of the nucleoprotein in pea epicotyls by synthetic auxins during induction of root formation].

Root initiation in etiolated pea epicotyls induced by NAA and 2,4-D is inhibited by application of 5-BU in the same way as root initiation induced with IAA. The time of 5-BU action is regulated by auxin concentration. Binding of auxins to carefully extracted nucleoproteins from pea epicotyls at pH 8 resulted in a decrease of the melting point (T m) of the nucleoproteins. From the results it is concluded that auxins act by direct binding to the nucleoprotein (probably by ionic bonds) and that this binding induces a decrease in binding capacity of histone to DNA, which represents the first step in the initiation of RNA synthesis.