caa a22 4500 397522754 CHVBK 20180308164637.0 cr unu---uuuuu 161202e199509 xx s 000 0 eng 10.1093/jxb/46.9.1177 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.9.1177 Vulnerability of xylem to embolism in relation to leaf water potential and stomatal conductance in Fagus sylvatica f. purpurea and Populus balsamifera [Elektronische Daten] [U. Hacke, J.J. Sauter] The vulnerability of xylem vessels to water stress-induced cavitation was studied by measuring hydraulic conductivity and ultrasound acoustic emissions (AEs) in Fagus sylvatica L. f. purpurea (Ait.) Schneid. and Populus balsamifera L. The occurrence of xylem embolism in summer was investigated in relation to leaf water potential and stomatal conductance. Populus was extremely vulnerable to cavitation, losing functional vessels due to embolism at water potentials lower than −0.7 MPa. Fagus experienced embolism when water potential fell below −1.9 MPa. Midday water potentials often approached these threshold values. When evaporative demand increased rapidly on sunny days, water loss became limited by low stomatal conductance. Thus water potentials fell only slightly below the threshold values inducing cavitation. Despite the differences in vulnerability, both species tolerated a similar embolism rate of about 10% in the summer. There was no embolism reversal during prolonged periods of rain. AEs were predictive of loss in hydraulic conductivity, indicating that AEs were mainly confined to vessels. Finally, vessel length distribution, vessel diameter (tangential axis), vessel density, and vessel wall thickness had been determined for both species investigated. Populus had longer and wider vessels than Fagus, whereas vessel wall thickness was similar in both species. © Oxford University Press RESEARCH PAPERS nationallicence Acoustic emissions nationallicence Fagus nationallicence Populus nationallicence stomatal closure nationallicence xylem embolism nationallicence Hacke U. Botanisches Institut der Christian-Albrechts-Universität zu Kiel, Oishausenstraβe 40, D-24098 Kiel, Germany aut Sauter J.J. Botanisches Institut der Christian-Albrechts-Universität zu Kiel, Oishausenstraβe 40, D-24098 Kiel, Germany aut Journal of Experimental Botany Oxford University Press 46/9(1995-09), 1177-1183 0022-0957 46:9<1177 1995 46 exbotj https://doi.org/10.1093/jxb/46.9.1177 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.9.1177 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hacke U. Botanisches Institut der Christian-Albrechts-Universität zu Kiel, Oishausenstraβe 40, D-24098 Kiel, Germany aut NATIONALLICENCE 700 1- Sauter J.J. Botanisches Institut der Christian-Albrechts-Universität zu Kiel, Oishausenstraβe 40, D-24098 Kiel, Germany aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/9(1995-09), 1177-1183 0022-0957 46:9<1177 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford