散孔材与环孔材树种枝干、叶水力学特性的比较研究

ISWC OpenIR > 水保所知识产出(1956---)

	散孔材与环孔材树种枝干、叶水力学特性的比较研究
其他题名	Comparison of hydraulic traits in branches and leaves of diffuse-and ringporous
	左力翔; 李俊辉; 李秧秧; 赵丽敏
	2012
发表期刊	生态学报
卷号	32 期号:16 页码:5087-5094
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。
其他摘要	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 diffuseporous 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 rehydrated from a range of water potentials ( ψleaf ) ． Kleaf was measured by assessing kinetics of ψleaf relaxation upon leaf rehydration． The results showed that branch cross-sectional area-based maximum specific conductivities ( Ks-max ) of the ring-porous species were greater than those of the diffuse-porous species． Ring-porous species were more vulnerable to cavitation ( P50 branch ) than diffuse-porous species and a tradeoff relationship was evident between Ks-max and P50branch in branches． No differences were found between leaf water transport capacities ( Kl-max ) or the vulnerability to hydraulic dysfunction ( P50leaf ) in the two species types，and there was no tradeoff relationship between Kl-max and P50leaf ． In the three diffuse-porous species，leaves were more vulnerable than branches to water stress-induced dysfunction，but in the ring-porous species， branches were more vulnerable than leaves． Pearson correlation analysis indicated that there was no correlation between branch and leaf hydraulic traits ( Kmax and P50) in the six investigated woody species． These results suggest that in our study: ( 1 ) diffuse-porous and ring-porous species diverged mainly in branch but not in leaf hydraulics，so that leaf hydraulics alone cannot be used to explain the differences between these two tree types in ecological function and adaptation． ( 2) Branch and leaf hydraulic traits were relatively independent and may be correlated with branch and leaf structure，respectively．
关键词	散孔材 Diffuse-porous Species 环孔材 Ring-porous Species 枝干和叶 Branch And Leaf 水力学性质 Hydraulic Traits
语种	中文
文献类型	期刊论文
条目标识符	sbir.nwafu.edu.cn/handle/361005/5416
专题	水保所知识产出(1956---)
推荐引用方式 GB/T 7714	左力翔,李俊辉,李秧秧,等. 散孔材与环孔材树种枝干、叶水力学特性的比较研究[J]. 生态学报,2012,32(16):5087-5094.
APA	左力翔,李俊辉,李秧秧,&赵丽敏.(2012).散孔材与环孔材树种枝干、叶水力学特性的比较研究.生态学报,32(16),5087-5094.
MLA	左力翔,et al."散孔材与环孔材树种枝干、叶水力学特性的比较研究".生态学报 32.16(2012):5087-5094.

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