Inter-genotypic differences in drought tolerance of maritime pine are modified by elevated [CO2]

Background and Aims Despite the importance of growth [CO2] and water availability for tree growth and survival, little information is available on how the interplay of these two factors can shape intraspecific patterns of functional variation in tree species, particularly for conifers. The main objective of the study was to test whether the range of realized drought tolerance within the species can be affected by elevated [CO2]. Methods Intraspecific variability in leaf gas exchange, growth rate and other leaf functional traits were studied in clones of maritime pine. A factorial experiment including water availability, growth [CO2] and four different genotypes was conducted in growth rooms. A 'water deficit' treatment was imposed by applying a cycle of progressive soil water depletion and recovery at two levels of growth [CO2] 'ambient [CO2]' (aCO2 400 lmol mol-1) and 'elevated [CO2]' (eCO2 800 lmol mol-1). Key Results eCO2 had a neutral effect on the impact of drought on growth and leaf gas exchange of the most drought-sensitive genotypes while it aggravated the impact of drought on the most drought-tolerant genotypes at aCO2. Thus, eCO2 attenuated genotypic differences in drought tolerance as compared with those observed at aCO2. Genotypic variation at both levels of growth [CO2] was found in specific leaf area and leaf nitrogen content but not in other physiological leaf traits such as intrinsic water use efficiency and leaf osmotic potential. eCO2 increased Δ13C but had no significant effect on δ18O. This effect did not interact with the impact of drought, which increased d18O and decreased Δ13C. Nevertheless, correlations between Δ13C and δ18O indicated the non-stomatal component of water use efficiency in this species can be particularly sensitive to drought. Conclusions Evidence from this study suggests elevated [CO2] can modify current ranges of drought tolerance within tree species. © The Author 2017.

Bibliographic Details

Main Authors:	Sánchez-Gómez, D., Mancha, J. A., Cervera, M. T., Aranda García, Ismael
Format:	artículo biblioteca
Language:	English
Published:	Oxford University Press 2017
Subjects:	Carbon isotope ratio, Chlorophyll fluorescence, Drought tolerance, Elevated [CO2], Intraspecific variability, Leaf nitrogen content, Oxygen isotope ratio, Photosynthetic rate, Pinus pinaster, Specific leaf area, Water deficit, Water use efficiency,
Online Access:	http://hdl.handle.net/20.500.12792/5467 http://hdl.handle.net/10261/293013
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