The pleurogram, an under-investigated functional trait in seeds

Ailton G. Rodrigues-Junior, Carol C. Baskin, Jerry M. Baskin, Orlando C. De-Paula

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Background: A structure called the pleurogram makes up a large part of the seed coat of some species in subfamilies Caesalpinioideae and Mimosoideae of Fabaceae, but little is known about its function. It has been hypothesized that this structure acts as a hygroscopic valve during the maturation drying of seeds. However, a new hypothesis has recently emerged that proposes a distinct function for the pleurogram. Scope: Here, we provide an overview of the structure and function of the pleurogram, which is diverse and complex. This large structure can be dislodged, thereby creating a pathway for water entry into water-impermeable seeds. However, the pleurogram is non-functional as a pathway of water into the seed of some species. Thus, the evolutionary history of species with a pleurogram may be related to a loss/gain in its function. A complete model for the function of the pleurogram is proposed. Conclusions: The pleurogram may act on several stages of the seed, from maturation to germination. As a hygroscopic valve, it regulates dehydration of the seed during maturation. As a pathway for water entry into the seed, the pleurogram acts as a water gap in seeds with physical dormancy, thereby regulating dormancy break/germination. The occurrence of a pleurogram in several genera of legumes and Cucurbitaceae is confirmed. Single or multiple pleurograms can serve as (the) point(s) of water entry into seeds that do not otherwise have a hilar water gap.

Original languageEnglish
Pages (from-to)167-174
Number of pages8
JournalAnnals of Botany
Issue number2
StatePublished - Feb 1 2021

Bibliographical note

Publisher Copyright:
© 2020 The Author(s) 2020. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail:


  • Functional seed trait
  • legumes
  • physical dormancy break
  • seed drying
  • seed germination
  • water gap

ASJC Scopus subject areas

  • Plant Science


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