The hormonal control of wheat leaf unrolling.

The unrolling of etiolated wheat leaf sections in the dark is stimulated by the application of gibberellic acid (GA3). GA3 is most effective if applied for a short time at the beginning of incubation. Kinetin also stimulated leaf unrolling in the dark. AMO1618 and CCC inhibit red light and kinetin-stimulated unrolling. Gibberellin-like substances extracted from red light-treated leaf tissue are effective in stimulating leaf unrolling.Ethylene production in leaf sections is stimulated by IAA, GA3 and kinetin and inhibited by ABA. A brief exposure to red light decreases the ability of the tissue to produce ethylene. It is concluded that ethylene plays no important role in the control of leaf unrolling by red light or by the application of hormones.