Impact of freeze–thaw-induced pit aspiration on stem water transport in the subalpine conifer Abies veitchii

编号 040037301

推送时间 20221212

研究领域 森林培育 

年份 2022 

类型 期刊 

语种 英语

标题 Impact of freeze–thaw-induced pit aspiration on stem water transport in the subalpine conifer Abies veitchii

来源期刊 Plant Physiology

期 第373期

发表时间 20220823

关键词 Abies veitchii;  freeze–thaw-induced;  embolism;  pit aspiration;  drought stress;  stem water transport; 

摘要 During winter, subalpine conifers experience frequent freeze–thaw cycles in stem xylem that may cause embolism and pit aspiration due to increased water volume during the sap to ice transition. This study examined the occurrence and ecological impacts of a combination of freeze–thaw-induced pit aspiration and embolism triggered by natural and artificial stem freezing. In subalpine Veitch’s fir (Abies veitchii) trees, the fraction of closed pits and embolized tracheids as well as conductivity losses were measured to examine pit aspiration and its effects. When trees incurred mild drought stress in February and early March, 70%–80% of stem conductivity was lost. Cryo-scanning electron microscopy indicated <20% embolized tracheids but ～90% closed pits. Severe drought stress in late March caused 96%?±?1.2% (mean?±?standard error) loss of stem conductivity, while the fraction of embolized tracheids increased to 64%?±?6.6%, and aspirated pit fraction decreased to 23%?±?5.6%. Experimental freeze–thaw cycles also increased pit aspiration from 7.1%?±?0.89% to 49%?±?10%, and the fraction of closed pits was positively correlated to the percent loss of stem hydraulic conductivity. The results indicated that freezing-induced pit aspiration is an important factor for stem xylem dysfunction under mild drought, and upon severe drought in winter; stem water transport is predominantly inhibited by xylem embolism.

服务人员 孙小满

服务院士 尹伟伦

PDF文件 浏览全文