干旱胁迫下毛白杨和元宝槭的水力学调控  

Hydraulic regulation of Populus tomentosa and Acer truncatum under drought stress

作　　者：伍敏 田雨 樊大勇 张祥雪[1] WU Min;TIAN Yu;FAN Da-Yong;ZHANG Xiang-Xue(College of Science,Beijing Forestry University,Beijing 100083,China;College of Biological Science and Technology,Beijing Forestry University,Beijing 100083,China;Key Laboratory for Silviculture and Conservation of Ministry of Education,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学理学院,北京100083 [2]北京林业大学生物科学与技术学院,北京100083 [3]北京林业大学森林培育与保护教育部重点实验室,北京100083

出　　处：《植物生态学报》2022年第9期1086-1097,共12页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31670625)。

摘　　要：毛白杨(Populus tomentosa)和元宝槭(Acer truncatum)是华北平原人工林的主要树种,研究两者水力结构和干旱-复水过程中茎非结构性碳水化合物(NSC)含量动态,可揭示其水力学调控策略,为全球气候变化背景下华北人工林水分平衡的科学管理提供理论依据。该研究以相同生境下分布的毛白杨和元宝槭幼树为研究材料,测量两者的茎抗栓塞能力与水力安全阈、水力面积、叶膨压损失点等水力结构参数;开展干旱-复水实验,测定茎NSC含量动态以及干旱胁迫解除后复水阶段的木质部栓塞修复能力。结果表明:毛白杨导水率损失50%对应的水势(-1.289 MPa)高于元宝槭(-2.894 MPa),且膨压损失点时的渗透势低,水力安全阈小,木材密度小,气孔调节偏向于变水行为,表现为易栓塞的低水势忍耐脱水耐旱特性,水分调节对策趋于冒险;元宝槭则倾向于不易栓塞的高水势延迟脱水耐旱特性,水分调节对策趋于保守。在干旱-复水实验中,毛白杨可溶性糖、淀粉和茎NSC含量先减后增,元宝槭则先增后减;并且毛白杨表现出比元宝槭更高的栓塞修复能力,这与植物体内茎NSC含量变化差异具有一定联系。毛白杨较高的栓塞修复能力也为其易栓塞的低水势忍耐脱水耐旱特性及冒险的水分调节对策提供水力安全保障。两树种在水力学调控上表现出的较大差异可能与其生活史特性相关。Aims The tree decline and death caused by drought stress under global climate change is a topic of general interest in ecological research.Different tree species in the same habitat can adopt various hydraulic strategies to maintain water balance in order to deal with drought stress.Populus tomentosa and Acer truncatum are the main tree species in plantations in the North China Plain.Studies on their hydraulic structure and dynamics of non-structural carbohydrate(NSC)content during drought-rehydration can reveal their hydraulic regulation strategies and provide theoretical basis for scientific management of water balance in plantations in north China under the background of global climate change.Methods By using the saplings of P.tomentosa and A.truncatum distributed in the same habitat,we measured the hydraulic structure parameters,such as the resistance to embolism and hydraulic safety margin of stem,hydraulic areas,osmotic potential at leaf turgor pressure loss point,etc.Dehydration and rehydration were carried out to investigate the dynamics of stem NSC content,and to examine the repair capacity of xylem embolism in the rehydration stage after drought stress removel.Important findings The results showed that the water potential of P.tomentosa(-1.289 MPa)when xylem hydraulic conductivity lost 50%was higher than that of A.truncatum(-2.894 MPa).Populus tomentosa also presented lower osmotic potential at turgor pressure loss point,narrower hydraulic safety margin,smaller wood density,and tended to have anisohydry behavior of stomatal regulation,indicating that it was prone to embolism characterized with dehydration and drought tolerance at low water potential,and tended to have more risky water regulation strategies.Acer truncatum survived drought stress by“delayed dehydration”at high water potentials,and tended to have conservative water regulation strategy.In the dehydration-rehydration experiment,the contents of soluble sugar,starch and non-structural carbohydrate in stem of P.tomentosa decreased first and

关 键 词：水力学调控 水分调节对策 非结构性碳水化合物 栓塞修复 耐旱特性 

分 类 号：S718.5[农业科学—林学]