Abstract
Unravelling the complexities of transpiration can be assisted by understanding the oxygen isotope composition of transpired water vapour (δE). It is often assumed that δE is at steady state, thereby mirroring the oxygen isotope composition of source water (δsource), but this assumption has never been tested at the whole-tree scale. This study utilized the unique infrastructure of 12 whole-tree chambers enclosing Eucalyptus parramattensis E.C.Hall trees to measure δE along with concurrent temperature and gas exchange data. Six chambers tracked ambient air temperature and six were exposed to an ambient +3 ◦C warming treatment. Day time means for δE were within 1.2% of δsource (−3.3%) but varied considerably throughout the day. Our observations show that E. parramattensis trees are seldom transpiring at isotopic steady state over a diel period, but transpiration approaches source water isotopic composition over longer time periods.
Original language | English |
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Article number | tpae125 |
Number of pages | 13 |
Journal | Tree Physiology |
Volume | 44 |
Issue number | 11 |
DOIs | |
Publication status | Published - 1 Nov 2024 |
Bibliographical note
Publisher Copyright:© The Author(s) 2024. Published by Oxford University Press.
Keywords
- evapotranspiration
- organic material
- oxygen isotopes