Disentangling the effects of atmospheric CO2 and climate on intrinsic water-use efficiency in South Asian tropical moist forest trees
Rahman M, Islam M, Gebrekirstos A, Bräuning A (2020)
Publication Type: Journal article
Publication year: 2020
Journal
Book Volume: 40
Pages Range: 904-916
Journal Issue: 7
Abstract
Due to the increase in atmospheric CO2 concentrations, the ratio of carbon fixed by assimilation to water lost by transpiration through stomatal conductance (intrinsic water-use efficiency, iWUE) shows a long-term increasing trend globally. However, the drivers of short-term (inter-annual) variability in iWUE of tropical trees are poorly understood. We studied the inter-annual variability in iWUE of three South Asian tropical moist forest tree species (Chukrasia tabularis A.Juss., Toona ciliata M. Roem. and Lagerstroemia speciosa L.) derived from tree-ring stable carbon isotope ratio (δ13C) in response to variations of environmental conditions. We found a significantly decreasing trend in carbon discrimination (Δ13C) and an increasing trend in iWUE in all the three species, with a species-specific long-term trend in intercellular CO2 concentration (Ci). Growing season temperatures were the main driver of inter-annual variability of iWUE in C. tabularis and L. speciosa, whereas previous year temperatures determined the iWUE variability in T. ciliata. Vapor pressure deficit was linked with iWUE only in C. tabularis. Differences in shade tolerance, tree stature and canopy position might have caused this species-specific variation in iWUE response to climate. Linear mixed effect modeling successfully simulated iWUE variability, explaining 41-51% of the total variance varying with species. Commonality analysis revealed that temperatures had a dominant influence on the inter-annual iWUE variability (64-77%) over precipitation (7-22%) and atmospheric CO2 concentration (3-6%). However, the long-term variations in iWUE were explicitly determined by the atmospheric CO2 increase (83-94%). Our results suggest that the elevated CO2 and concomitant global warming might have detrimental effects on gas exchange and other physiological processes in South Asian tropical moist forest trees.
Authors with CRIS profile
Mizanur Rahman
Lehrstuhl für Geographie (Physische Geographie)
Mahmuda Islam
Institut für Geographie
Achim Bräuning
Lehrstuhl für Geographie (Physische Geographie)
Involved external institutions
Kenya (KE)How to cite
APA:
Rahman, M., Islam, M., Gebrekirstos, A., & Bräuning, A. (2020). Disentangling the effects of atmospheric CO2 and climate on intrinsic water-use efficiency in South Asian tropical moist forest trees. Tree Physiology, 40(7), 904-916. https://dx.doi.org/10.1093/treephys/tpaa043
MLA:
Rahman, Mizanur, et al. "Disentangling the effects of atmospheric CO2 and climate on intrinsic water-use efficiency in South Asian tropical moist forest trees." Tree Physiology 40.7 (2020): 904-916.
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