Graduated PhD 2018
The effects of drought, heat and elevated atmospheric CO2 on physiology and growth of Eucalyptus – Does climate-of-origin matter?
David Tissue, Sebastian Pfautsch, Victor Resco de Dios and Mark Tjoelker
Investigating genotypic responses of eucalypts to future climate conditions
Due to increased atmospheric carbon dioxide concentrations (eCO2), 2013 was the 37th year in a row that temperatures exceeded the annual global average of the last century, and was the hottest year on record in Australia. It is predicted that South East Australia will face increasing numbers of extreme climate events, including severe droughts and heat waves.
The Australian genus Eucalyptus is abundant in native forests and constitutes 10 % of the global forest plantation area. Thus, it is crucial to understand if a tree's climate of origin provides favorable characteristics that improve its tolerance to such climate events.
This project will address the role of genotypic (G) diversity in adjusting to variable environments (E) and their interaction (G X E) in response to soil water deficit and temperature stress.
Increased carbon assimilation and storage due to eCO2 can increase tree growth and reduce water loss via transpiration. On the other hand, higher temperatures can decrease photosynthesis and carbohydrate accumulation, and at the same time increase water use.
Genotypes of Eucalyptus originating from warmer climates may have a greater capacity to maintain productivity and physiological functioning in hot, dry environments compared with genotypes from cooler climates.
I will address the physiological mechanisms associated with this potential adjustment, and identify the genotypes that are most productive in future climates of eCO2, heat stress and drought. Potted tree seedlings will be grown under different stress environments in a greenhouse and compared regarding their gas exchange, leaf water potential, carbohydrate storage and tolerance-improving chemical solutes (osmolytes).
Results will be used to predict how climate change can impact native and plantation forests and evaluate potential shifts in plant communities.
Pfautsch S, Macfarlane C, Harbusch M, Wesolowski A, Smith RA, Boer MM, Tjoelker MG, Reich PB, Adams MA, (2016) 'Vessel diameter and related hydraulic traits of 31 Eucalyptus species arrayed along a gradient of water availability', Ecology (in press)
Pfautsch S, Harbusch M, Wesolowski A, Smith R, Macfarlane C, Tjoelker MG, Reich PB, Adams MA, (2016) 'Climate determines vascular traits in the ecologically diverse genus Eucalyptus', Ecology Letters, vol.19, no.3, pp 240-248