Meristem Initiation, Persistence and Reconstitution as Developmental Foundations of Life-history Diversity in Vascular Land Plants

Meristems create the developmental capacity for repeated organ production, architectural modification and recovery after damage in vascular land plants. Yet the frequently invoked connection between meristem organisation and plant ‘life style’ requires clearer separation of developmental mechanism from ecological consequence. This critical narrative review examines how shoot, root, axillary, intercalary and vascular meristems are initiated, maintained, recruited and reconstituted, and asks how these processes contribute to contrasting life histories and growth forms. Peer-reviewed molecular, genetic, anatomical, palaeobotanical, modelling and ecological literature was selected through targeted scholarly searching and citation-based examination, with emphasis on mechanistic and comparative evidence. A central finding is that stem-cell maintenance, meristem formation, bud persistence and post-disturbance organ regeneration are related but non-equivalent processes. The CLAVATA–WUSCHEL feedback system, auxin-dependent root patterning, KNOTTED-like meristem regulators and peptide-mediated cambial signalling establish persuasive mechanistic examples, although their evolutionary generality varies among vascular plant lineages. Comparative studies of lycophytes and fossils challenge simple narratives of a single ancestral root meristem, while studies of perennial flowering, seasonal dormancy and below-ground bud banks show how meristem persistence can sustain repeated reproduction or disturbance recovery. Causal links from molecular networks to lifetime fitness, however, remain less directly tested than developmental phenotypes. The review proposes an explicitly provisional framework in which meristem establishment, protected persistence, conditional activation and regenerative replacement constitute distinct components of a plant's developmental opportunity set. It identifies major gaps in phylogenetic sampling, cell-lineage resolution, long-term fitness measurement and integration of developmental dynamics with demographic and environmental models. Meristem biology offers a strong explanation for the potential range of plant architectures, but growth habit and ecological strategy emerge from interactions between meristem capacity, resource allocation, disturbance regimes and developmental history rather than from meristem identity alone.