Consistent spectral reflectance signatures of photosystem II thermal tolerance in contrasting foundation tree species

Consistent spectral reflectance signatures of photosystem II thermal tolerance in contrasting foundation tree species | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 19 September 2025 V1 Latest version Share on Consistent spectral reflectance signatures of photosystem II thermal tolerance in contrasting foundation tree species Authors : Benjamin Wiebe 0000-0002-9325-1540 [email protected] , Madeline E Moran 0000-0002-4464-8795 , Megan Seeley , Rebecca Senft , Alexandra Schuessler 0009-0007-4265-559X , Eleanor Thomson , Luiza Aparecido 0000-0001-8642-6632 , … Show All … , Hillary F Cooper 0000-0003-2634-1404 , Catherine Gehring , Kevin Hultine 0000-0001-9747-6037 , Dan F. Koepke 0009-0008-5728-1655 , Roberta E. Martin 0000-0003-3509-8530 , Bradley C Posch 0000-0003-0924-6608 , Andrew Richardson 0000-0002-0148-6714 , Thomas G Whitham , Gerard J Allan , Gregory P. Asner 0000-0001-7893-6421 , and Christopher Doughty 0000-0003-3985-7960 Show Fewer Authors Info & Affiliations https://doi.org/10.22541/au.175829691.15185387/v1 Published Journal of Geophysical Research: Biogeosciences Version of record Peer review timeline 190 views 177 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Photosystem II (PSII) is among the most thermally sensitive components of photosynthesis, and emerging evidence suggests that that plants in diverse biomes face increasing risk of PSII damage under future climate change. However, uncertainties in the distribution and drivers of PSII thermal tolerance (Tcrit) limit our ability to predict thermal risk in plant communities across spatial scales. Here, we evaluate whether intraspecific variation in Tcrit corresponds to leaf reflectance spectra (400-2500nm) to identify mechanisms associated with Tcrit in field conditions and evaluate the potential of its remote estimation using novel remote sensing platforms. We measured Tcrit using temperature response curves of minimal fluorescence (Fo) along with corresponding leaf reflectance spectra in two foundation tree species: Populus fremontii (US Southwest) and Metrosideros polymorpha (Hawai‘i). P. fremontii was sampled under both moderate (45ºC) heat. Consistent spectral signatures of Tcrit emerged across species and sampling conditions, with the strongest signatures in P. fremontii under extreme heat. These signatures allowed Tcrit estimation (R²=0.24-0.30; RMSE<1.0ºC) and classification of high- versus low-Tcrit (71-77% accuracy) in P. fremontii. Across both species, Tcrit tended to increase with spectral indices reflecting higher chlorophyll content and lower carotenoids, nonphotochemical quenching, and leaf water content. These findings suggest that variation in PSII thermal tolerance is linked to fundamental biochemical properties of leaves, which are reflected in their optical traits. As climate extremes intensify, spectral screening and scaling of Tcrit via remote sensing may support improved conservation, management, and thermal risk assessment in vulnerable ecosystems. Supplementary Material File (1043980_0_merged_1754342999.pdf) Download 1.37 MB File (wiebe_jgr_tcrit_spectroscopy.docx) Download 2.42 MB File (wiebe_jgr_tcrit_spectroscopy_supplemental_info.pdf) Download 1.10 MB Information & Authors Information Version history V1 Version 1 19 September 2025 Peer review timeline Published Journal of Geophysical Research: Biogeosciences Version of Record 27 Feb 2026 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Keywords leaf spectroscopy photosynthetic heat stress pigments psii thermal tolerance remote sensing Authors Affiliations Benjamin Wiebe 0000-0002-9325-1540 [email protected] Northern Arizona University View all articles by this author Madeline E Moran 0000-0002-4464-8795 Arizona State University View all articles by this author Megan Seeley Unknown View all articles by this author Rebecca Senft University of Utah View all articles by this author Alexandra Schuessler 0009-0007-4265-559X Desert Botanical Garden View all articles by this author Eleanor Thomson University of Oxford View all articles by this author Luiza Aparecido 0000-0001-8642-6632 University of Utah View all articles by this author Hillary F Cooper 0000-0003-2634-1404 Northern Arizona University View all articles by this author Catherine Gehring Northern Arizona University View all articles by this author Kevin Hultine 0000-0001-9747-6037 Desert Botanical Garden View all articles by this author Dan F. Koepke 0009-0008-5728-1655 Desert Botanical Garden View all articles by this author Roberta E. Martin 0000-0003-3509-8530 Arizona State University View all articles by this author Bradley C Posch 0000-0003-0924-6608 Desert Botanical Garden View all articles by this author Andrew Richardson 0000-0002-0148-6714 Northern Arizona University View all articles by this author Thomas G Whitham Northern Arizona University View all articles by this author Gerard J Allan Northern Arizona University View all articles by this author Gregory P. Asner 0000-0001-7893-6421 Arizona State University View all articles by this author Christopher Doughty 0000-0003-3985-7960 Northern Arizona University View all articles by this author Funding Information National Science Foundation DEB-2017877 Christopher Doughty Metrics & Citations Metrics Article Usage 190 views 177 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Benjamin Wiebe, Madeline E Moran, Megan Seeley, et al. Consistent spectral reflectance signatures of photosystem II thermal tolerance in contrasting foundation tree species. Authorea . 19 September 2025. DOI: https://doi.org/10.22541/au.175829691.15185387/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . 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