Periderm is a well‐known structural feature with vital roles in protection of inner plant tissues and wound healing. Despite its importance to plant survival, knowledge of periderm occurrences outside the seed plants is limited and the evolutionary origins of periderm remain poorly explored. Here, we review the current knowledge of the taxonomic distribution of periderm in its two main forms – canonical periderm (periderm formed as a typical ontogenetic stage) and wound periderm (periderm produced as a self‐repair mechanism) – with a focus on major plant lineages, living and extinct. We supplement the published occurrences with data based on our own observations and experiments. This updated body of data reveals that the distribution of wound periderm is more widespread taxonomically than previously recognized and some living and extinct groups are capable of producing wound periderm, despite canonical periderm being absent from their normal developmental program. A critical review of canonical and wound periderms in extant and fossil lineages indicates that not all periderms are created equal. Their organisation is widely variable and the differences can be characterised in terms of variations in three structural features: (
We analyze the oldest fossil occurrences of wound‐response periderm to characterize the development of wound responses in early tracheophytes. The origin of periderm production by a cambium (phellogen), an innovation with key roles in protection of inner plant tissues, is poorly explored; understanding periderm development in early tracheophytes can illuminate key aspects of this process. Anatomy of wound‐response tissues is characterized in serial sections in a new Early Devonian (Emsian; Characterizing development in these oldest periderm occurrences allows us to propose a model for the development of wound‐response periderm in early tracheophytes: by phellogen activity that is poorly coordinated laterally but bifacial, producing secondary tissues initially outwardly and subsequently inwardly. The earliest occurrences of wound periderm pre‐date the oldest known periderm produced systemically as a regular ontogenetic stage (canonical periderm), suggesting that periderm evolved initially as a wound‐response mechanism. We hypothesize that canonical periderm evolved by exaptation of this wound sealing mechanism, whose deployment was triggered by tangential tensional stresses induced in the superficial tissues by vascular cambial growth from within.
- NSF-PAR ID:
- 10418421
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 239
- Issue:
- 1
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 388-398
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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