水保所知识产出(1956---)知识库

植物水力学特性是当前植物水分关系研究的重要内容，直接决定着树木的抗旱
性和水分利用。本文通过对黄土高原丘陵区典型落叶木本植物的叶性状与 PV 曲线
参数之间关系、不同演替阶段的群落优势种山杨、白桦以及辽东栎水力学结构特性
以及典型灌木水力结构特性与木质部解剖结构的关系进行研究，试图揭示该区域典
型植物叶功能性状变化与植物生理耐旱性间的关系，阐明该区典型乔灌木的水力结
构差异及其结构基础，以为黄土高原退化生态系统恢复和重建提供理论基础。主要
研究结论如下：
（1）11 种供试树种的比叶质量与叶密度呈极显著正相关，叶密度与叶厚度呈
显著负相关；膨压损失点对应的渗透势（Ψ tlp ）和饱和渗透势（Ψ sat ）呈极显著正相
关关系，且 Ψ tlp 和束缚水含量（B）呈显著负相关关系。典范相关分析和 Pearson 相
关分析表明：叶性状和 PV 曲线参数两组变量间有一定的相关性，比叶质量与膨压
损失点对应的相对含水量呈显著负相关，而与叶密度之间的负相关关系也接近显
著。这些结果表明影响该区植物比叶质量的主要因素为叶密度，叶密度与厚度之间
存在一定的制约关系；渗透物质的积累和束缚水含量的增加是造成该区物种 Ψ tlp 降
低的主要原因；高比叶质量的物种 RWC tlp 低，耐旱性相对较强，从而揭示了比叶质
量高的物种抗旱的生理机制。
（2）辽东栎叶片的饱和渗透势（Ψ sat ）、膨压损失点对应的渗透势（Ψ tlp ）和相
对含水量（RWC tlp ）明显低于山杨和白桦，且有高的叶水容。辽东栎的的最大 K s
高于山杨和白桦，但 HV 值低于山杨和白桦，导致 3 种树种的最大 K l 差异不大。无
论是叶还是枝干，辽东栎抵抗栓塞的能力均大于山杨和白桦，其水分传输安全距离
（旱季叶最低水势 Ψ min 与导水率损失 50%时对应的叶或枝干木质部水势 Ψ 50 之差）
和叶对枝干的水力保护作用（叶与枝干的 Ψ 50 之差）也明显大于山杨和白桦。两种
演替早期树种山杨和白桦的水力结构特性差异不大。这些结果从水力学角度揭示了
演替顶极种辽东栎高的耐脱水能力、大的叶水容、相对强的抵抗栓塞能力和高的水
分传输安全性是其耐旱性强于演替早期种山杨和白桦的重要原因。
（3）子午岭林区 4 种典型灌木小枝枝干的最大比导水率（K s-max ）以狼牙刺为最大，其次为沙棘、山桃和黄刺玫，枝干木质部抵抗空穴化形成的能力为：黄刺玫>
山桃>沙棘>狼牙刺。4 种典型灌木枝干的最大比导水率与木质部导管平均直径和水
力直径呈显著正相关关系，与导管密度和木材密度呈显著负相关关系。4 种典型灌
木的抵抗空穴化能力与其木质部导管平均直径和木材密度呈显著负相关关系。表
明：导管直径和木材密度是影响黄土丘陵区典型灌木水分传输能力以及抵抗空穴化
形成能力的重要因素。
关键词：黄土丘陵区；落叶乔灌木；PV 参数；叶性状；水力结构

Plant hydraulic traits is an important aspect of plant water relations, and directly
determine plant drought-tolerance and whole-plant water use. In this paper, taking the
typical native deciduous woody plants growing on the Loess hilly region as the materials,
we explored the relationship between leaf traits and Pressure-Volume curve parameters
of eleven woody species, the hydraulic architecture traits of three tree species from
different successional stages and of four shrubs. The main purposes were to reveal the
relationship between the leaf functional traits and the physiological drought tolerance of
the typical woody plants in this area and to clarify the hydraulic architecture differences
of the typical trees and shrubs and their anatomical basis, thus to provide certain
theoretical basis for the restoration and reconstruction of degraded ecosystems on the
Loess Plateau. The main results were as follows:
（1）Among the leaf traits of the eleven tested species, leaf mass per area（LMA）
was positively correlated with leaf density （LD）but uncorrelated with leaf thickness （LT）,
LD was negatively correlated with LT. Osmotic potential at turgor loss point（Ψ tlp ）was
positively correlated with saturated osmotic potential （Ψ sat ）and negatively correlated with
binding water proportion（B）across tested species. Canonical correlation and Pearson
correlation indicated that there was relation between leaf traits group and PV parameters
group, LMA was negatively correlated with relative water content at turgor loss point
（RWC tlp ）and close to negatively correlated with LD. All these showed that LMA
variation was caused by LD rather than LT, there was a tradeoff relationship between LD
and LT. Solutes accumulation was the major reason of decreased Ψ tlp . Higher LMA was  was associated with lower RWC tlp , demonstrating the physiological basis of species with
higher LMA also have stronger drought-tolerance.
（2）Quercus liaotungensis had lower Ψ sat , Ψ tlp , RWC tlp and higher leaf capacitance
（C leaf ）than Populus davidiana and Betula platyphylla. Quercus liaotungensis had
higher maximum K s and lower HV than early succession species Populus davidiana and
Betula platyphylla, thus maximum K l for these three species was the same. For both leaf
and branch, Quercus liaotungensis was more resistant to embolism than Populus
davidiana and Betula platyphylla, meanwhile, Quercus liaotungensis also had a larger
hydraulic safety margin when balanced by the difference of minimum leaf water
potential during dry season （Ψ min ）and xylem water potential corresponding to 50% loss
of conductivities （Ψ 50 ）, and larger leaf hydraulic protection for branch when estimated by
the difference between leaf Ψ 50 and branch Ψ 50 . No hydraulic architecture difference was
found for two early succession species Populus davidiana and Betula platyphylla. These
results demonstrated from plant hydraulics that higher dehydration tolerance, larger leaf
capitance, stronger leaf and branch embolism resistance, higher hydraulic safety at
Quercus liaotungensis may be responsible for its higher drought tolerance than erarly
succession species Populus davidiana and Betula platyphylla.
（3）The twig branches of Sophora viciifolia had the largest maximum hydraulic
conductivity（K s-max ）among the four typical shrubs in Ziwuling forest zone, followed by
Hippophae rhamnoides, Prunus davidiana and Rosa xanthina. Rosa xanthina had the
strongest xylem cavitation resistance, followed by Prunus davidiana, Hippophae
rhamnoides and Sophora viciifolia. Across the four tested shrubs, K s-max was positively
correlated with the mean diameter of vessel lumen and hydraulic diameter of vessel
lumen and negatively correlated with conduit density and wood density. Meanwhile, the
cavitation resistance was negatively correlated with the mean diameter of vessel lumen
and wood density. All these results indicated that: conduit diameter and wood density
were key factors affecting the hydraulic conductivity and the cavitation resistance of the
typical shrubs on the Loess Hilly Area.
Key Words：Loess hilly region; deciduous trees and shrubs; PV parameters; leaf traits;
hydraulic architecture