University Of Tasmania

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Drought responses of two gymnosperm species with contrasting stomatal regulation strategies under elevated [CO2] and temperature

journal contribution
posted on 2023-05-19, 05:45 authored by Duan, H, Anthony O'GradyAnthony O'Grady, Duursma, RA, Choat, B, Huang, G, Smith, RA, Jiang, Y, Tissue, DT
Future climate regimes characterized by rising [CO2], rising temperatures and associated droughts may differentially affect tree growth and physiology. However, the interactive effects of these three factors are complex because elevated [CO2] and elevated temperature may generate differential physiological responses during drought. To date, the interactive effects of elevated [CO2] and elevated temperature on drought-induced tree mortality remain poorly understood in gymnosperm species that differ in stomatal regulation strategies. Water relations and carbon dynamics were examined in two species with contrasting stomatal regulation strategies: Pinus radiata D. Don (relatively isohydric gymnosperm; regulating stomata to maintain leaf water potential above critical thresholds) and Callitris rhomboidea R. Br (relatively anisohydric gymnosperm; allowing leaf water potential to decline as the soil dries), to assess response to drought as a function of [CO2] and temperature. Both species were grown in two [CO2] (Ca (ambient, 400 μl l−1) and Ce (elevated, 640 μl l−1)) and two temperature (Ta (ambient) and Te (ambient +4 °C)) treatments in a sun-lit glasshouse under well-watered conditions. Drought plants were then exposed to a progressive drought until mortality. Prior to mortality, extensive xylem cavitation occurred in both species, but significant depletion of non-structural carbohydrates was not observed in either species. Te resulted in faster mortality in P. radiata, but it did not modify the time-to-mortality in C. rhomboidea. Ce did not delay the time-to-mortality in either species under drought or Te treatments. In summary, elevated temperature (+4 °C) had greater influence than elevated [CO2] (+240 μl l−1) on drought responses of the two studied gymnosperm species, while stomatal regulation strategies did not generally affect the relative contributions of hydraulic failure and carbohydrate depletion to mortality under severe drought.


Publication title

Tree Physiology: An International Botanical Journal










School of Natural Sciences


Heron Publishing

Place of publication

202, 3994 Shelbourne St, Victoria, Canada, Bc, V8N 3E2

Rights statement

Copyright 2015 The Author

Repository Status

  • Restricted

Socio-economic Objectives

Ecosystem adaptation to climate change