The Role of Light in Leaf and Flower Bud Break of the Peach (<i>Prunus persica</i>)

Abstract

Abstract The effect of light on peach leaf and flower bud break was examined. It was found that leafless dormant shoots were light‐perceptive organs. Darkness, after light preconditioning during dormancy, reduced leaf bud opening; however, light was obligatory when the shoots were preconditioned in the dark. Relatively short exposures to light were sufficient to stimulate leaf bud break. Terminal buds were less inhibited by darkness than were laterals. Flower bud break was inhibited in light after dark preconditioning. The red region of the spectrum was found to be active; the phytochorome system seems to be involved in the light reactions, as the red light effect was reversible with subsequent far‐red illumination. Supplementary light, producing long‐day conditions, could partly compensate for insufficient chilling. A possible sequence of reactions in the plant is suggested.