Sensitivity cycling in physically dormant seeds of the Neotropical tree Senna multijuga (Fabaceae)

A. G. Rodrigues-Junior, C. C. Baskin, J. M. Baskin, Q. S. Garcia

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Cycling of sensitivity to physical dormancy (PY) break has been documented in herbaceous species. However, it has not been reported in tree seeds, nor has the effect of seed size on sensitivity to PY-breaking been evaluated in any species. Thus, the aims of this study were to investigate how PY is broken in seeds of the tropical legume tree Senna multijuga, if seeds exhibit sensitivity cycling and if seed size affects induction into sensitivity. Dormancy and germination were evaluated in intact and scarified seeds from two collections of S. multijuga. The effects of temperature, moisture and seed size on induction of sensitivity to dormancy-breaking were assessed, and seasonal changes in germination and persistence of buried seeds were determined. Reversal of sensitivity was also investigated. Fresh seeds were insensitive to dormancy break at wet–high temperatures, and an increase in sensitivity occurred in buried seeds after they experienced low temperatures during winter (dry season). Temperatures ≤20 °C increased sensitivity, whereas temperatures ≥30 °C decreased it regardless of moisture conditions. Dormancy was broken in sensitive seeds by incubating them at 35 °C. Sensitivity could be reversed, and large seeds were more sensitive than small seeds to sensitivity induction. Seeds of S. multijuga exhibit sensitivity cycling to PY-breaking. Seeds become sensitive during winter and can germinate with the onset of the spring–summer rainy season in Brazil. Small seeds are slower to become sensitive than large ones, and this may be a mechanism by which germination is spread over time. Sensitive seeds that fail to germinate become insensitive during exposure to drought during summer. This is the first report of sensitivity cycling in a tree species.

Original languageEnglish
Pages (from-to)698-706
Number of pages9
JournalPlant Biology
Issue number4
StatePublished - Jul 2018

Bibliographical note

Publisher Copyright:
© 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands


  • Natural PY break
  • neotropical tree species
  • physical dormancy
  • seed size-mediated sensitivity
  • survival strategies

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science


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