Estimating the equilibrium position by measuring growth stress in weeping branches of Prunus spachiana Kitamura f. spachiana cv. Plenarosea

Abstract

The equilibrium position of a current-year branch of the weeping Japanese cherry, Prunus spachiana Kitamura f. spachiana cv. Plenarosea, was estimated by measuring the released strains of growth stresses. In current-year branches that were supported with wires to prevent weeping as soon as the branches first budded, tensile growth stresses on the upper side were smaller than those of the control branches. Gelatinous fibers were rarely found on the upper part of the cross section of the supported branches, whereas the control branches had many gelatinous fibers on the upper part. The upright orientation of the supported branches was closer to the equilibrium position than the weeping orientation of the control branches. The equilibrium position of the branches was thought to be in the initial bud direction, above the horizontal plane; and the weeping style of branch was not the preferred angular orientation for P. spachiana.