@article{0c025377be524c00813381a6ef7a4b5a,
title = "Insights into source/sink controls on wood formation and photosynthesis from a stem chilling experiment in mature red maple",
abstract = "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.",
keywords = "anatomy, growth, nonstructural carbon, phloem, sink, source, wood, xylogenesis",
author = "Tim Rademacher and Patrick Fonti and LeMoine, {James M.} and Fonti, {Marina V.} and Francis Bowles and Yizhao Chen and Eckes-Shephard, {Annemarie H.} and Friend, {Andrew D.} and Richardson, {Andrew D.}",
note = "Funding Information: TR, ADR, ADF and YC acknowledge support from the Natural Environment Research Council – National Science Foundation International Collaboration program under grant nos. NE/P011462/1 and DEB‐1741585. ADR and TR also acknowledge the support from the National Science Foundation under grants DEB‐1237491 and DEB‐1832210. The authors thank David Basler, Teemu H{\"o}llt{\"a}, Henrik Hartmann and Christian K{\"o}rner for discussion of the ideas, Mark von Scoy, Elise Miller, and Shawna Greyeyes for help in the field, and Shawna Greyeyes, Amberlee Pavey and Angelina Valenzuela for help in the laboratory. The authors also thank David Basler for sharing the orthomosaics of the site. AHE‐S acknowledges support from the European Research Council under the European Union Horizon 2020 programme (758873). This study contributes to the strategic research areas BECC and MERGE. Funding Information: TR, ADR, ADF and YC acknowledge support from the Natural Environment Research Council – National Science Foundation International Collaboration program under grant nos. NE/P011462/1 and DEB-1741585. ADR and TR also acknowledge the support from the National Science Foundation under grants DEB-1237491 and DEB-1832210. The authors thank David Basler, Teemu H{\"o}llt{\"a}, Henrik Hartmann and Christian K{\"o}rner for discussion of the ideas, Mark von Scoy, Elise Miller, and Shawna Greyeyes for help in the field, and Shawna Greyeyes, Amberlee Pavey and Angelina Valenzuela for help in the laboratory. The authors also thank David Basler for sharing the orthomosaics of the site. AHE-S acknowledges support from the European Research Council under the European Union Horizon 2020 programme (758873). This study contributes to the strategic research areas BECC and MERGE. Publisher Copyright: {\textcopyright} 2022 The Authors. New Phytologist {\textcopyright} 2022 New Phytologist Foundation.",
year = "2022",
month = nov,
doi = "10.1111/nph.18421",
language = "English (US)",
volume = "236",
pages = "1296--1309",
journal = "New Phytologist",
issn = "0028-646X",
publisher = "Wiley-Blackwell",
number = "4",
}