Standardsignatur
Titel
Responses of Norway spruce (Picea abies (L.) Karst.) to water deficiency : 3rd EUROSILVA Workshop, Obergurgl, Austria, September, 10-14, 1998
Verfasser
Erscheinungsjahr
1999
Seiten
S. 183-190
Illustrationen
5 Abb., 11 Lit.
Material
Unselbständiges Werk
Datensatznummer
200086145
Quelle
Abstract
The aim of the investigations was to comprehensively characterise the tree water regime of spruce trees in locations of higher elevation in Eastern Ore Mountains and its modification resulting from water deficiency and decline. By means of an experimental simulation of water deficiency, concerning three 40-year-old spruce trees, physiological changes which occurred under long-term and extreme drought stress could be observed. Since the beginning of this experiment in spring of 1996 a continuously decreasing water supply has been detected by diminshing values of the pre-dawn water potential. This fact causes higher values of diurnal water potential diminution (from pre-dawn until noon) in 1996 in comparison to the reference trees. During the subsequent growing season these values decreased, while drought stress continued to occur. The decreasing sap flow rate and changing values of pre-dawn water potential, osmotic potential and turgor during the whole period from 1996 indicated different degrees of stress. The continued physiological activity and the obvious recovery of the experimental trees in spite of long-term drought conditions with extinct water supply from the soil suggest absorption of dew by needles as explanation. This hypothesis is supported by a respective laboratory experiment. These results emphasize the importance of dew, mist and short showers during drought periods for the water balance of trees.