Stomatal conductance and intrinsic water use efficiency in the drought year 2003: a case study of European beech
Beech trees were able to cope with the drought of 2003. Harmful water shortage has been avoided by an effective stomatal closure while use of carbon storage pools may have prevented carbon starvation and growth reduction.
We applied hydrodynamic modeling together with a tree ring stable isotope approach to identify the physiological responses of beech trees to changing environmental conditions. The drought conditions of the extreme hot and dry summer in 2003 were hypothesized to significantly influence the radial growth of European beech mainly triggered by the stomatal response towards water scarcity leading, in turn, to a decline in carbon assimilation. The functional–structural single tree modeling approach applied, revealed in fact a strong limitation of water use and carbon gain during drought. However, tree ring width data did not show a clear drought response and no differentiation in radial growth during six subsequent years examined (2002–2007) has been observed. Using integrated results from mechanistic carbon–water balance simulations, tree ring carbon and oxygen isotope analysis and tree ring width measurements we postulate that the suggested drought-induced growth decline has been prevented by the remobilization of stored carbohydrates, an early onset in growth and the relatively late occurrence of the severe drought in 2003. Furthermore, we demonstrate that the stomatal response played a significant role in avoiding harmful water tension that would have caused xylem dysfunction. As a result of the combined investigation with physiological measurements (stable isotope approach) and hydrodynamic modeling of stomatal aperture, we could give insights into the physiological control of mature beech tree functioning under drought. We conclude that beech trees have been operating at their hydraulic limits and that the longer or repeated drought periods would have affected the growth considerably.
KeywordsFagus sylvatica Intrinsic water use efficiency Leaf physiology Stomatal conductance Carbon and oxygen stable isotopes Hydrodynamic modeling
This study was conducted as part of the joint research project ‘The carbon and water balance and the development of beech dominated forests—Physiological and competitive mechanisms on different scale levels’ with funding from the German Research Foundation (DFG) to AG under contract numbers GE 1090/8-1 and 9-1.
- Adams HD, Guardiola-Claramonte M, Barron-Gafford GA et al (2009) Temperature sensitivity of drought-induced tree mortality portends increased regional die-off under global-change-type drought. Proc Natl Acad Sci USA 106:7063–7066. doi: 10.1073/pnas.0901438106 PubMedCentralPubMedCrossRefGoogle Scholar
- Aranda I, Gil L, Pardos JA (2005) Seasonal changes in apparent hydraulic conductance and their implications for water use of European beech (Fagus sylvatica L.) and sessile oak [Quercus petraea (Matt.) Liebl.] in South Europe. Plant Ecol 179:155–167. doi: 10.1007/s11258-004-7007-1 CrossRefGoogle Scholar
- ASCE-EWRI (2005) The ASCE Standardized Reference Evapotranspiration Equation (1801) Technical Committee Report to the Environmental and Water Resources Institute of the American Society of Civil Engineers from the Task Committee on Standardization of Reference Evapotranspiration. ASCE-EWRI, Alexander Bell Drive, RestonGoogle Scholar
- Brandes E, Wenninger J, Koeniger P, Schindler D, Rennenberg H, Leibundgut C, Mayer H, Gessler A (2007) Assessing environmental and physiological controls over water relations in a Scots pine (Pinus sylvestris L.) stand through analyses of stable isotope composition of water and organic matter. Plant Cell Environ 30:113–127. doi: 10.1111/j.1365-3040.2006.01609.x PubMedCrossRefGoogle Scholar
- Development Core Team R (2010) R: A language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Farquhar GD, Lloyd J (1993) Carbon and oxygen isotope effects in the exchange of carbon dioxide between terrestrial plants and the atmosphere. In: JR Ehleringer, AE Hall, GD Farquhar (eds) Stable isotopes and plant carbon-water relations, pp. 47–70. Academic Press, Inc., San Diego, CA. doi: 10.1016/B978-0-08-091801-3.50011-8
- Fiala J, Cernikovsky L, Leeuw Fd, Kurfuerst P (eds) (2003) Air pollution by ozone in Europe in summer 2003. European Environment Agency, CopenhagenGoogle Scholar
- Gessler A, Rennenberg H, Keitel C (2004b) Stable isotope composition of organic compounds transported in the phloem of European beech—Evaluation of different methods of phloem sap collection and assessment of gradients in carbon isotope composition during leaf-to-stem transport. Plant Biol 6:721–729. doi: 10.1055/s-2004-830350 PubMedCrossRefGoogle Scholar
- Keitel C, Adams MA, Holst T et al (2003) Carbon and oxygen isotope composition of organic compounds in the phloem sap provides a short-term measure for stomatal conductance of European beech (Fagus sylvatica L.). Plant Cell Environ 26:1157–1168. doi: 10.1046/j.1365-3040.2003.01040.x CrossRefGoogle Scholar
- Korn S (2004) Experimentelle Untersuchung der Wasseraufnahme und der hydraulischen Eigenschaften des Wurzelsystems. Dissertation. University of GöttingenGoogle Scholar
- Nahm M, Radoglou K, Halyvopoulos G, Geßler A, Rennenberg H, Fotelli MN (2006) Physiological performance of beech (Fagus sylvatica L.) at its southeastern distribution limit in Europe: seasonal changes in nitrogen, carbon and water balance. Plant Biology 8:52–63. doi: 10.1055/s-2005-872988 PubMedCrossRefGoogle Scholar
- Nahm M, Matzarakis A, Rennenberg H, Geßler A (2007) Seasonal courses of key parameters of nitrogen, carbon and water balance in European beech (Fagus sylvatica L.) grown on four different study sites along a European North-South climate gradient during the 2003 drought. Trees-Structure and Function 21:79–92. doi: 10.1007/s00468-006-0098-7 CrossRefGoogle Scholar
- Peñuelas J, Hunt JM, Ogaya R, Jump AS (2008) Twentieth century changes of tree-ring δ 13C at the southern range-edge of Fagus sylvatica: increasing water-use efficiency does not avoid the growth decline induced by warming at low altitudes. Glob Chang Biol 14:1076–1088. doi: 10.1111/j.1365-2486.2008.01563.x CrossRefGoogle Scholar
- Priesack E (2006) Expert-N Dokumentation der Modellbibliothek. Forschungsverbund Agrarökosysteme München. FAM-Bericht 60. Hieronimus. MünchenGoogle Scholar
- Priesack E, Bauer C (2003) Expert-N Datenmanagement. Forschungsverbund Agrarökosysteme München. FAM-Bericht 59. Hieronimus. MünchenGoogle Scholar
- Thornley JHM (2002) Instantaneous canopy photosynthesis: analytical expressions for sun and shade leaves based on exponential light decay down the canopy and an acclimated non-rectangular hyperbola for leaf photosynthesis. Ann Bot 89:451–458. doi: 10.1093/aob/mcf071 PubMedCentralPubMedCrossRefGoogle Scholar
- Van der Werf GW, Sass-Klaassen UGW, Mohren GMJ (2007) The impact of the 2003 summer drought on the intra-annual growth pattern of beech (Fagus sylvatica L.) and oak (Quercus robur L.) on a dry site in the Netherlands. Dendrochronologia 25:103–112. doi: 10.1016/j.dendro.2007.03.004 CrossRefGoogle Scholar