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Annemarie Eckes-Shephard

Annemarie Eckes-Shephard

Researcher

Annemarie Eckes-Shephard

Insights into source/sink controls on wood formation and photosynthesis from a stem chilling experiment in mature red maple

Author

  • Tim Rademacher
  • Patrick Fonti
  • James M LeMoine
  • Marina V Fonti
  • Francis Bowles
  • Yizhao Chen
  • Annemarie H Eckes-Shephard
  • Andrew D Friend
  • Andrew D Richardson

Summary, in English

Whether sources or sinks control wood growth remains debated with a paucity of evidence from mature trees in natural settings. Here, we altered carbon supply rate in stems of mature red maples (Acer rubrum) within the growing season by restricting phloem transport using stem chilling; thereby increasing carbon supply above and decreasing carbon supply below the restrictions, respectively. Chilling successfully altered nonstructural carbon (NSC) concentrations in the phloem without detectable repercussions on bulk NSC in stems and roots. Ring width responded strongly to local variations in carbon supply with up to seven-fold differences along the stem of chilled trees; however, concurrent changes in the structural carbon were inconclusive at high carbon supply due to large local variability of wood growth. Above chilling-induced bottlenecks, we also observed higher leaf NSC concentrations, reduced photosynthetic capacity, and earlier leaf coloration and fall. Our results indicate that the cambial sink is affected by carbon supply, but within-tree feedbacks can downregulate source activity, when carbon supply exceeds demand. Such feedbacks have only been hypothesized in mature trees. Consequently, these findings constitute an important advance in understanding source-sink dynamics, suggesting that mature red maples operate close to both source- and sink-limitation in the early growing season.

Department/s

  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • MERGE: ModElling the Regional and Global Earth system
  • Dept of Physical Geography and Ecosystem Science

Publishing year

2022-11

Language

English

Pages

1296-1309

Publication/Series

New Phytologist

Volume

236

Issue

4

Document type

Journal article

Publisher

Wiley-Blackwell

Topic

  • Environmental Sciences
  • Other Biological Topics

Keywords

  • anatomy
  • growth
  • nonstructural carbon
  • phloem
  • sink
  • source
  • wood
  • xylogenesis

Status

Published

Project

  • Redefining the carbon sink capacity of global forests: The driving role of tree mortality

ISBN/ISSN/Other

  • ISSN: 1469-8137