Increasing air humidity influences hydraulic efficiency but not functional vulnerability of xylem in hybrid aspen.

摘要: Abstract Climate models predict greater increases in the frequency than amount of precipitation and a consequent rise atmospheric humidity at high latitudes by end century. We investigated responses hydraulic relevant anatomical traits xylem to elevated relative air on 1-yr-old coppice hybrid aspen ( Populus  ×  wettsteinii ) growing experimental stand Free Air Humidity Manipulation site Eastern Estonia. The conductivity stems was measured with pressure flow meter; artificial cavitation stem segments induced injection method. Specific decreased from 4.42 control 3.94 kg m −1  s  MPa humidification treatment, while trend well correlated increasing wood density. Humidified trees exhibited smaller leaf area same cross-sectional area, resulting 34% higher average Huber values compared control. Control humidity-treated differed neither native embolism level nor susceptibility dehydration-induced cavitation. Increasing reduces efficiency expressed basis causes substantial changes resource allocation between photosynthetic water transport tissues. This climate does not influence vulnerability