Insight into Canary Island pine physiology provided by stable isotope patterns of water and plant tissues along an altitudinal gradient

0547820 - BÚ 2022 RIV GB eng J - Journal Article
Miranda, J. C. - Lehmann, M. M. - Saurer, M. - Altman, Jan - Treydte, K.
Insight into Canary Island pine physiology provided by stable isotope patterns of water and plant tissues along an altitudinal gradient.
Tree Physiology. Roč. 41, č. 9 (2021), s. 1611-1626. ISSN 0829-318X. E-ISSN 1758-4469
R&D Projects: GA ČR GJ20-05840Y; GA MŠMT(CZ) LTAUSA19137
Institutional support: RVO:67985939
Keywords : stable isotopes * tree rings * vapor pressure deficit
OECD category: Ecology
Impact factor: 4.561, year: 2021
Method of publishing: Limited access

We found a decreasing δ18 Oxygen trend in source water that was overridden by an increasing δ18 Oxygen trend in needle water, leaf assimilates and tree-ring cellulose with increasing altitude, suggesting site-specific tree physiological responses to relative humidity. Fog-influenced and fog-free sites showed similar δ13 Carbon values, suggesting photosynthetic activity to be limited by stomatal closure and irradiance at certain periods. In addition, we observed an 18 Oxygen-depletion (fog-free and timberline sites) and 13 Carbon-depletion (fog-influenced and fog-free sites) in latewood compared with earlywood caused by seasonal differences in: (i) water uptake (i.e., deeper ground water during summer drought, fog water frequency and interception) and (ii) meteorological conditions (stem radial growth and latewood δ18 Oxygen correlated with winter precipitation). In addition, we found evidence for foliar water uptake and strong isotopic gradients along the pine needle axis in water and assimilates. These gradients are likely the reason for an unexpected underestimation of pine needle water δ18 Oxygen when applying standard leaf water δ18 Oxygen models. Our results indicate that soil water availability and air humidity conditions are the main drivers of the physiological behavior of pine along the Canary Island’s altitudinal gradients.
Permanent Link: http://hdl.handle.net/11104/0323990