关键词: 渗透势, 耐旱性, 叶片水力特性, 永久萎蔫点, 树木死亡率, 木本物种, 气候变化

Abstract:

The last years, Central European forests have suffered from drought as a direct consequence of climate change. All these forests have a long management history and it lies in the landowner’s responsibility to replant damaged forests. Hence, landowners and the government are searching currently for species suitable to replant in areas affected by tree die-offs. It is a matter of fact that good knowledge of drought resistance of species is a critical measure for the current replanting efforts. We determined a widely recognized trait for leaf drought tolerance (leaf water potential at turgor loss point at full hydration, π_tlp) in 41 woody species native or introduced in Central Europe. The osmometric rapid assessment method was used to measure the leaf osmotic potential at full hydration (π_osm) of sun-exposed leaves and converted to π_tlp. Mean π_tlp of the native species was −2.33 ± 0.33 MPa. The less negative π_tlp was found in the introduced species Aesculus hypocastania and was at −1.70 ± 0.11 MPa. The most negative π_tlp, and thus the potentially highest drought tolerance, were found in the introduced species Pseudotsuga menzesii and was at −3.02 ± 0.14 MPa. High or less negative π_tlp is associated with lower drought tolerance, whereas low or more negative π_tlp stands for higher resistance to drought stress. For example, the two native species Illex aquifolium and Alnus glustinosa are species naturally associated with moist habitats and are characterized by the least negative π_tlp of −1.75 ± 0.02 and −1.76 ± 0.03 MPa, respectively.

Key words: osmotic potential, drought tolerance, leaf hydraulic trait, permanent wilting point, tree mortality, woody species, climate change