Cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads
Abstract We report a biophysical mechanism, termed cryocampsis (Greek cryo-, cold, + campsis, bending), that helps northern shrubs bend downward under a snow load. Subfreezing temperatures substantially increase the downward bending of cantilever-loaded branches of these shrubs, while allowing them...
Published in: | PNAS Nexus |
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Oxford University Press (OUP)
2022
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Online Access: | http://dx.doi.org/10.1093/pnasnexus/pgac131 https://academic.oup.com/pnasnexus/advance-article-pdf/doi/10.1093/pnasnexus/pgac131/45059906/pgac131.pdf https://academic.oup.com/pnasnexus/article-pdf/1/4/pgac131/48849425/pgac131.pdf |
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croxfordunivpr:10.1093/pnasnexus/pgac131 2024-02-11T10:01:01+01:00 Cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads Ray, Peter M Bret-Harte, M Syndonia Nelson, Karen E National Science Foundation 2022 http://dx.doi.org/10.1093/pnasnexus/pgac131 https://academic.oup.com/pnasnexus/advance-article-pdf/doi/10.1093/pnasnexus/pgac131/45059906/pgac131.pdf https://academic.oup.com/pnasnexus/article-pdf/1/4/pgac131/48849425/pgac131.pdf en eng Oxford University Press (OUP) https://creativecommons.org/licenses/by-nc-nd/4.0/ PNAS Nexus volume 1, issue 4 ISSN 2752-6542 journal-article 2022 croxfordunivpr https://doi.org/10.1093/pnasnexus/pgac131 2024-01-12T09:38:46Z Abstract We report a biophysical mechanism, termed cryocampsis (Greek cryo-, cold, + campsis, bending), that helps northern shrubs bend downward under a snow load. Subfreezing temperatures substantially increase the downward bending of cantilever-loaded branches of these shrubs, while allowing them to recover their summer elevation after thawing and becoming unloaded. This is counterintuitive, because biological materials (including branches that show cryocampsis) generally become stiffer when frozen, so should flex less, rather than more, under a given bending load. Cryocampsis involves straining of the cell walls of a branch’s xylem (wood), and depends upon the branch being hydrated. Among woody species tested, cryocampsis occurs in almost all Arctic, some boreal, only a few temperate and Mediterranean, and no tropical woody species that we have tested. It helps cold-winter climate shrubs reversibly get, and stay, below the snow surface, sheltering them from winter weather and predation hazards. This should be advantageous, because Arctic shrub bud winter mortality significantly increases if their shoots are forcibly kept above the snow surface. Our observations reveal a physically surprising behavior of biological materials at subfreezing temperatures, and a previously unrecognized mechanism of woody plant adaptation to cold-winter climates. We suggest that cryocampsis’ mechanism involves the movement of water between cell wall matrix polymers and cell lumens during freezing, analogous to that of frost-heave in soils or rocks. Article in Journal/Newspaper Arctic Oxford University Press Arctic PNAS Nexus |
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Open Polar |
collection |
Oxford University Press |
op_collection_id |
croxfordunivpr |
language |
English |
description |
Abstract We report a biophysical mechanism, termed cryocampsis (Greek cryo-, cold, + campsis, bending), that helps northern shrubs bend downward under a snow load. Subfreezing temperatures substantially increase the downward bending of cantilever-loaded branches of these shrubs, while allowing them to recover their summer elevation after thawing and becoming unloaded. This is counterintuitive, because biological materials (including branches that show cryocampsis) generally become stiffer when frozen, so should flex less, rather than more, under a given bending load. Cryocampsis involves straining of the cell walls of a branch’s xylem (wood), and depends upon the branch being hydrated. Among woody species tested, cryocampsis occurs in almost all Arctic, some boreal, only a few temperate and Mediterranean, and no tropical woody species that we have tested. It helps cold-winter climate shrubs reversibly get, and stay, below the snow surface, sheltering them from winter weather and predation hazards. This should be advantageous, because Arctic shrub bud winter mortality significantly increases if their shoots are forcibly kept above the snow surface. Our observations reveal a physically surprising behavior of biological materials at subfreezing temperatures, and a previously unrecognized mechanism of woody plant adaptation to cold-winter climates. We suggest that cryocampsis’ mechanism involves the movement of water between cell wall matrix polymers and cell lumens during freezing, analogous to that of frost-heave in soils or rocks. |
author2 |
Nelson, Karen E National Science Foundation |
format |
Article in Journal/Newspaper |
author |
Ray, Peter M Bret-Harte, M Syndonia |
spellingShingle |
Ray, Peter M Bret-Harte, M Syndonia Cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads |
author_facet |
Ray, Peter M Bret-Harte, M Syndonia |
author_sort |
Ray, Peter M |
title |
Cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads |
title_short |
Cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads |
title_full |
Cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads |
title_fullStr |
Cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads |
title_full_unstemmed |
Cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads |
title_sort |
cryocampsis: a biophysical freeze-bending response of shrubs and trees under snow loads |
publisher |
Oxford University Press (OUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1093/pnasnexus/pgac131 https://academic.oup.com/pnasnexus/advance-article-pdf/doi/10.1093/pnasnexus/pgac131/45059906/pgac131.pdf https://academic.oup.com/pnasnexus/article-pdf/1/4/pgac131/48849425/pgac131.pdf |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
PNAS Nexus volume 1, issue 4 ISSN 2752-6542 |
op_rights |
https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1093/pnasnexus/pgac131 |
container_title |
PNAS Nexus |
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1790596741351866368 |