Physiological maturation and hormonal profiles associated with rooting performance and root system architecture of leafy cuttings in Prunus subhirtella ‘Autumnalis’

The success of vegetative propagation in woody ornamentals is strongly influenced by the physiological age and positional origin of donor shoots, yet the underlying mechanisms linking topophytic origin, hormonal dynamics, and root system quality remain unclear. This study examined adventitious rooting, root system morphology, and endogenous phytohormone profiles in basal (inner/lower crown) and terminal (outer/upper crown) leafy cuttings of Prunus subhirtella ‘Autumnalis’ from a mature 60-year-old tree. Despite similar rooting success between cutting types (66.7%), basal cuttings produced more extensive root systems, with greater total length, surface area, and numbers of tips and forks, whereas terminal cuttings formed thicker roots and a higher proportion of coarse roots (> 2 mm). Free indole-3-acetic acid (IAA) peaked at 4 hours post-severance in both types. However, terminal cuttings exhibited elevated levels of IAA conjugates and oxidative metabolites, as well as transiently higher jasmonic acid immediately after excision indicating that they exhibited stronger stress after wounding compared with basal cuttings. In contrast, the basal cuttings maintained higher indole-3-butyric acid (IBA) and distinct 4-chloro-indole-acetic acid (4-Cl-IAA) dynamics. These results suggest that differences in auxin metabolism and jasmonate dynamics shape root system morphology and quality. Integrating topophytic origin and hormonal profiling provides valuable insights for optimizing clonal propagation and improving root system performance in woody ornamentals.