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Leaf Shedding and Non-Stomatal Limitations of Photosynthesis Mitigate Hydraulic Conductance Losses in Scots Pine Saplings During Severe Drought Stress

Nadal-Sala, Daniel 1; Grote, Rüdiger ORCID iD icon 1; Birami, Benjamin 1; Knüver, Timo 1; Rehschuh, Romy 1; Schwarz, Selina ORCID iD icon 1; Ruehr, Nadine K. ORCID iD icon 1
1 Institut für Meteorologie und Klimaforschung – Atmosphärische Umweltforschung (IMK-IFU), Karlsruher Institut für Technologie (KIT)

Abstract (englisch):

During drought, trees reduce water loss and hydraulic failure by closing their stomata, which also limits photosynthesis. Under severe drought stress, other acclimation mechanisms are trigged to further reduce transpiration to prevent irreversible conductance loss. Here, we investigate two of them: the reversible impacts on the photosynthetic apparatus, lumped as non-stomatal limitations (NSL) of photosynthesis, and the irreversible effect of premature leaf shedding. We integrate NSL and leaf shedding with a state-of-the-art tree hydraulic simulation model (SOX+) and parameterize them with example field measurements to demonstrate the stress-mitigating impact of these processes. We measured xylem vulnerability, transpiration, and leaf litter fall dynamics in Pinus sylvestris (L.) saplings grown for 54 days under severe dry-down. The observations showed that, once transpiration stopped, the rate of leaf shedding strongly increased until about 30% of leaf area was lost on average. We trained the SOX+ model with the observations and simulated changes in root-to-canopy conductance with and without including NSL and leaf shedding. Accounting for NSL improved model representation of transpiration, while model projections about root-to-canopy conductance loss were reduced by an overall 6%. ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000137875
Veröffentlicht am 23.09.2021
DOI: 10.3389/fpls.2021.715127
Zitationen: 34
Web of Science
Zitationen: 32
Zitationen: 39
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung – Atmosphärische Umweltforschung (IMK-IFU)
Institut für Meteorologie und Klimaforschung (IMK)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 09.2021
Sprache Englisch
Identifikator ISSN: 1664-462X
KITopen-ID: 1000137875
HGF-Programm 12.11.24 (POF IV, LK 01) Adaptation of natural landscapes to climate change
Weitere HGF-Programme 12.11.22 (POF IV, LK 01) Managed ecosystems as sources and sinks of GHGs
Erschienen in Frontiers in plant science
Verlag Frontiers Media SA
Band 12
Seiten Art. Nr.: 715127
Projektinformation DFG, DFG EIN, RU 1657/2-1_I
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Vorab online veröffentlicht am 03.09.2021
Nachgewiesen in Web of Science
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