Quantitative Morphology of Stump Sprouts Reveals a Common Growth Axis and a Reproducible Basal Longitudinal Cavity in an Ornamental Cherry
Stump sprouts may originate from pre-existing preventitious buds or adventitious buds, but whether these developmental origins produce distinguishable whole-shoot phenotypes remains unclear. We examined all visible sprouts on a single stump of an ornamental cherry (Prunus sp.) and measured four preselected traits: fresh weight, basal diameter, shoot length, and node number. The initial census comprised 35 sprouts. These traits were strongly correlated and were dominated by a common multivariate growth axis. Unsupervised mixture modelling identified statistical components within the morphological distribution, but these components could not be assigned to preventitious or adventitious developmental origins. During subsequent examination, we identified an unexpected basal longitudinal cavity and recorded its presence and axial length. The cavity occurred in 23 of 31 sectioned sprouts (74%). After complete removal of the initial sprout population, all visible sprouts were collected again seven days later. This second cohort comprised 22 substantially smaller sprouts but reproduced the coordinated whole-shoot growth structure. Remarkably, the basal longitudinal cavity occurred in 16 of 22 sprouts (73%), nearly identical to its initial frequency despite the marked difference in shoot size. Cavity presence was largely independent of overall shoot size, whereas cavity length increased with size among cavity-positive sprouts. Thus, gross quantitative morphology did not discriminate the hypothesized developmental origins, whereas basal anatomy revealed a reproducible feature potentially informative of developmental history. Direct anatomical and ontogenetic analyses are required to determine whether the basal longitudinal cavity is associated with sprout origin.