Drought stress reactions of different populations of Quercus robur L. and tilia cordata Mill

Abstract

Locally adapted trees and shrubs are suggested to show higher fitness at their site of origin than non-locally adapted ones. The production in tree nurseries could take this into account to improve outplanting performance. However, separate production of specific ecotypes in nurseries increases the costs of production and may reduce the availability of a specific species. In this study, we investigated drought stress reactions of 2 year-old container-grown seedlings of Quercus robur L. and Tilia cordata Mill. from four and three different populations, respectively, each from a different site of origin. Slow- and fast-developing drought stress treatments were applied in a greenhouse study to determine any difference in drought tolerance. Control plants were well irrigated. Depending on the species and stress development, only marginal interpopulation differences in particular physiological (pre-dawn water potential, stomatal conductance, relative water content) and/or biochemical (glucose, fructose, sucrose, starch, proline) reactions to drought existed. These differences did not consistently reflect precipitation conditions at the population sites of origin, indicating only low level of local adaptation for populations of the target species.