散孔材与环孔材树种枝干、叶水力学特性的比较研究  

Comparison of hydraulic traits in branches and leaves of diffuse-and ringporous species

作　　者：左力翔[1,2] 李俊辉[3] 李秧秧[2,3] 赵丽敏[1,2] 

机构地区：[1]西北农林科技大学资环学院,杨凌712100 [2]西北农林科技大学黄土高原土壤侵蚀与旱地农业国家重点实验室,杨凌712100 [3]中国科学院水利部水土保持研究所,杨凌712100

出　　处：《生态学报》2012年第16期5087-5094,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(3107054);中国科学院创新团队国际合作伙伴计划项目资助

摘　　要：为揭示散孔材与环孔材树种树木水分生理特性的差异,选取了常见的3种散孔材落叶树种(毛白杨、法国梧桐和樱花)和3种环孔材落叶树种(刺槐、合欢和白蜡),研究了其枝干与叶水力学性质的差异及其协调性。结果表明:3种环孔材树种枝干横截面积基础上的最大比导水率(Ks-max)大于3种散孔材树种,但其木质部对空穴化的脆弱性(P50branch)高于散孔材树种,6种树木枝干的水分传输能力和抵抗空穴化能力之间存在一种相互制约的权衡关系。3种散孔材与3种环孔材树种的叶最大水力导度(Kl-max)和水力脆弱性(P50leaf)并无显著差异;对于3种散孔材树种,叶的水力脆弱性要高于枝干,但对3种环孔材树种而言,枝干的水力脆弱性要高于叶。6种树木枝干和叶的水力学性质(Kmax、P50)之间并无相关关系。这些结果表明:散孔材与环孔材树种的枝干水力学特性有明显差异,但叶水力学特性无差异;枝干与叶水力学性质之间是相互独立的。Angiosperm tree species in temperate regions are broadly divided into diffuse-porous and ring-porous species based on their xylem anatomy.Diffuse-porous species show very little distinction between the diameter of vessel elements in early versus late wood,while ring-porous species have a bimodal distribution of vessel diameters associated with large,early season vessels and small late season vessels.These anatomical differences result in differences between these two kinds of tree species in stem water transport capacity and in the vulnerability to drought-induced cavitation.However,it is not clear if diffuse-porous and ring-porous species show differences in leaf hydraulic traits.Water transport resistance in leaves accounts for 30%—80% of the total hydraulic resistance of the whole-plant water transport pathway,and relatively few studies have focused on leaf hydraulics owing to methodological barriers;hence,elucidating the differences between diffuse-porous versus ring-porous species in leaf hydraulics and in leaf hydraulic trait coordination with stem hydraulic traits can be helpful in demonstrating the differences between diffuse-porous and ring-porous tree species in plant water use,geological distribution,leaf phenology and ecological adaptation. We compared hydraulic traits of branches and leaves in three diffuse-porous deciduous tree species（Populus tomentosa,Platanus hispanica,Prunus serrulata） and three ring-porous deciduous tree species（Robinia pseudoacacia,Albizia julibrissin,Fraxinus chinensis） growing in northwestern China.Branch and leaf water transport capacity was evaluated by their maximum hydraulic conductivities（Kmax）,and the hydraulic vulnerability was evaluated with P50,which corresponds to the branch or leaf water potential at 50% loss of maximum hydraulic conductivities.For stems,P50 was inferred from the vulnerability curves generated by air injection or bench dehydration method.For leaves,the curves were constructed by measuring hydraulic conductance（Kleaf） in leaves re

关 键 词：散孔材 环孔材 枝干和叶 水力学性质 

分 类 号：S718.4[农业科学—林学]