2026/08/04 by Adam Miodek, Aldona Paulina Miodek, Paweł Kojs
paper · doi:10.1007/s00226-026-01791-6
crossref issued 2026/08/04 · crossref published 2026/08/04 · crossref published-online 2026/08/04 · crossref created 2026/08/04 · crossref deposited 2026/08/04 · crossref indexed 2026/08/04 · crossref published-print 2026/09/01
Abstract Radial stem growth in trees and shrubs is a fundamental process influencing their development and adaptation. Traditionally, radial growth has been attributed primarily to the radial expansion of cambial cells and their derivatives. In this study, we investigated the contributions of both the tips and bodies of wood fibers to radial growth in black locust. An anatomical and statistical approach was applied to the analysis of collected plant tissues, including the vascular cambium and secondary xylem, which were prepared using a Tesla ultramicrotome. Our study indicated that, beyond commonly recognized radial enlargement of cells associated with cell wall growth, secondary xylem radial enlargement within black locust is also driven by fiber development in two distinct ways: (1) axial intrusive growth coupled with transverse expansion of wood fiber tips, and (2) shape transformation of developing fiber bodies in the transverse plane, from rectangular to more circular forms. We hypothesize that this mechanism may provide an adaptive advantage by optimizing resource allocation while maintaining mechanical stability, since transverse enlargement of fiber bodies appears to occur without substantial structural carbon investment prior to secondary cell wall deposition. These findings offer a novel developmental perspective on wood formation in black locust by challenging the classical paradigm of symplastic growth in the secondary xylem differentiation zone. These new insights may have implications for optimizing wood production and for advancing our fundamental understanding of developmental mechanisms in angiosperm woody plants.