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Peltier DMP, Carbone MS, McIntire CD, Robertson N, Thompson RA, Malone S, LeMoine J, Richardson AD, McDowell NG, Adams HD, Pockman WT, Trowbridge AM. Carbon starvation following a decade of experimental drought consumes old reserves in Pinus edulis. THE NEW PHYTOLOGIST 2023; 240:92-104. [PMID: 37430467 DOI: 10.1111/nph.19119] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 06/12/2023] [Indexed: 07/12/2023]
Abstract
Shifts in the age or turnover time of non-structural carbohydrates (NSC) may underlie changes in tree growth under long-term increases in drought stress associated with climate change. But NSC responses to drought are challenging to quantify, due in part to large NSC stores in trees and subsequently long response times of NSC to climate variation. We measured NSC age (Δ14 C) along with a suite of ecophysiological metrics in Pinus edulis trees experiencing either extreme short-term drought (-90% ambient precipitation plot, 2020-2021) or a decade of severe drought (-45% plot, 2010-2021). We tested the hypothesis that carbon starvation - consumption exceeding synthesis and storage - increases the age of sapwood NSC. One year of extreme drought had no impact on NSC pool size or age, despite significant reductions in predawn water potential, photosynthetic rates/capacity, and twig and needle growth. By contrast, long-term drought halved the age of the sapwood NSC pool, coupled with reductions in sapwood starch concentrations (-75%), basal area increment (-39%), and bole respiration rates (-28%). Our results suggest carbon starvation takes time, as tree carbon reserves appear resilient to extreme disturbance in the short term. However, after a decade of drought, trees apparently consumed old stored NSC to support metabolism.
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Affiliation(s)
- Drew M P Peltier
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Mariah S Carbone
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Cameron D McIntire
- Northeastern Area State, Private, and Tribal Forestry, USDA Forest Service, 271 Mast Road, Durham, NH, 03824, USA
| | - Nathan Robertson
- Biology Department, University of New Mexico, Albuquerque, NM, 87106, USA
| | - R Alex Thompson
- School of the Environment, Washington State University, Pullman, WA, 99163, USA
| | - Shealyn Malone
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Jim LeMoine
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Andrew D Richardson
- Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, 86011, USA
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Lab, PO Box 999, Richland, WA, 99352, USA
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA, 99164, USA
| | - Henry D Adams
- School of the Environment, Washington State University, Pullman, WA, 99163, USA
| | - William T Pockman
- Biology Department, University of New Mexico, Albuquerque, NM, 87106, USA
| | - Amy M Trowbridge
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI, 53706, USA
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