Growth Responses of Peach Roots and Shoots to Soil and Foliar-applied Paclobutrazol

Abstract

Abstract Paclobutrazol applied at 37 mg per plant to container-grown, own-rooted peach [ Prunus persica (L.) Batsch ‘Redhaven’] trees reduced vegetative growth (compared with no treatment) as measured by shoot extension, leaf size, and shoot dry weight. All paclobutrazol treatments (foliar and/or soil) increased root tip diameter and reduced unsuberized root length. Paclobutrazol increased the size of the cortex parenchyma cells and resulted in radial rather than longitudinal elongation of the innermost layer of cortex cells. These changes in cell shape and size were primarily responsible for increasing root tip diameter. Chemical name used: ( R *, R *)-(±)-β-[(4-chlorophenyl)methy]-α-(l,l-dimethylethyl)-1 H- 1,2,4-triazole-l-ethanol (paclobutrazol).