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Dying by drying: Timing of physiological stress thresholds related to tree death is not significantly altered by highly elevated CO 2
Author(s) -
Gattmann Marielle,
Birami Benjamin,
Nadal Sala Daniel,
Ruehr Nadine Katrin
Publication year - 2021
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13937
Subject(s) - acclimatization , water stress , turgor pressure , horticulture , stress (linguistics) , environmental science , chemistry , zoology , biology , botany , linguistics , philosophy
Abstract Drought‐induced tree mortality is expected to occur more frequently under predicted climate change. However, the extent of a possibly mitigating effect of simultaneously rising atmospheric [CO 2 ] on stress thresholds leading to tree death is not fully understood, yet. Here, we studied the drought response, the time until critical stress thresholds were reached and mortality occurrence of Pinus halepensis (Miller). In order to observe a large potential benefit from eCO 2 , the seedlings were grown with ample of water and nutrient supply under either highly elevated [CO 2 ] (eCO 2 , c . 936 ppm) or ambient (aCO 2 , c . 407 ppm) during 2 years. The subsequent exposure to a fast or a slow lethal drought was monitored using whole‐tree gas exchange chambers, measured leaf water potential and non‐structural carbohydrates. Using logistic regressions to derive probabilities for physiological parameters to reach critical drought stress thresholds, indicated a longer period for halving needle starch storage under eCO 2 than aCO 2 . Stomatal closure, turgor loss, the duration until the daily tree C balance turned negative, leaf water potential at thresholds and time‐of‐death were unaffected by eCO 2 . Overall, our study provides for the first‐time insights into the chronological interplay of physiological drought thresholds under long‐term acclimation to elevated [CO 2 ].