Developmental versus environmental control of early leaf phenology in juvenile Ohio buckeye (Aesculus glabra)

Carol K Augspurger

Research output: Contribution to journalArticle

Abstract

The spring phenology of juveniles of many canopy tree species in deciduous forests predates that of adult conspecifics. To determine whether the earlier phenology of seedlings of Aesculus glabra Willd. (Ohio buckeye) in Illinois, U.S.A., is developmentally or environmentally controlled, seedlings of five maternal parents were grown either in the understory or above a barn roof, simulating environmental conditions experienced at canopy height. Relative to canopy seedlings, understory seedlings had significantly earlier bud break (mean = 6 d), leaf expansion (8 d), leaf senescence (23 d), and leaf drop (18 d). Bud break and leaf expansion of canopy seedlings equalled that of canopy trees of Ohio buckeye, but senescence and leaf drop of canopy seedlings predated canopy trees by 45 and 67 d, respectively. Overall, results show evidence for environmental control over the spring phenology of juveniles. Thermal sums in spring accumulated more rapidly in the forest understory where nighttime temperatures were warmer than above the barn roof. Thus, the environmental control of spring phenology appears to be a non-stage-specific temperature cue that accumulates at different rates along the forest's vertical gradient. In contrast, senescence and leaf drop, while somewhat responsive to the environment, displayed strong developmental constraint.

Original languageEnglish (US)
Pages (from-to)31-36
Number of pages6
JournalCanadian Journal of Botany
Volume82
Issue number1
DOIs
StatePublished - Jan 1 2004

Keywords

  • Bud break
  • Developmental constraint
  • Leaf drop
  • Leaf expansion
  • Leaf senescence
  • Thermal sums

ASJC Scopus subject areas

  • Plant Science

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