ISWC OpenIR  > 水保所知识产出(1956---)
立地条件和树龄对刺槐和小叶杨叶水力 学特性的影响
李俊辉
Subtype硕士
Thesis Advisor李秧秧
2012-05
Degree Grantor中国科学院研究生院
Place of Conferral北京
Keyword刺槐 小叶杨 立地条件 树龄 叶水力学特性 叶生理生态性状
Abstract

立地条件和树龄是影响黄土高原“小老树”形成的主要因素。为此,本文以形成
黄土高原“小老树”的两个典型树种刺槐和小叶杨为对象,研究了不同立地条件(水
分好的沟谷台地和水分相对差的峁坡坡地)和树龄对两种树木叶水力学性质,叶形态
和生理特性及抗旱性的影响,目的在于揭示“小老树”形成的水力生理机制。主要结
论如下:
(1)水分好的台地上生长的两种树木叶最大水力导度明显大于水分差的坡地,
且随树龄增加,两种树木的叶最大水力导度明显下降。台地上生长的两种树木的叶表
皮导度和PV 曲线参数(膨压损失点时的相对含水量RWCtlp、膨压损失点时的水势ψtlp、
饱和含水量时的渗透势ψsat)均大于坡地;随树龄增加,两种树木的叶表皮导度显著下
降,PV 曲线参数出现不同程度的下降。两种树木叶最大水力导度和ψtlp 呈显著正相关,
表明叶最大水力导度和抗旱性之间存在一种制约关系。
(2)水分好的台地上生长的两种树木叶水力脆弱性(P50)和水分传输的安全性
更高;但随树龄增加,水力脆弱性差异不大,水分传输的安全性降低。两种树木叶P50
和PV 曲线参数之间存在一定的相关性,表明叶水力脆弱性是两种树木不同树龄阶段
重要的抗旱性特征之一。
(3)坡地刺槐和小叶杨具有小的叶面积,高的比叶质量和叶厚度,低的比叶水
力导度、净光合速率和气孔导度,而水分利用效率和N、P 养分含量均增加。随树龄
增加,两种树种的形态和生理特性表现出干旱生境中的特点,叶水分关系的恶化和分
配到光合器官中的N 含量比例的减少是随树龄增加净光合速率降低的重要原因。立地
条件和树龄对两种树种的一些重要的叶形态和生理特性表现出显著的交互作用,表明
干旱与树龄增加相互作用导致的光合面积的减少、叶片结构和建造成本的上升及净光
合速率的下降是黄土高原“小老树”形成的重要原因。
关键词:刺槐小叶杨立地条件树龄叶水力学特性叶生理生态性状

Other Abstract

Site and tree age are major factors of forming small dwarf tree on the Loess Plateau.
Thus, taking two typical tree species of small dwarf trees on the Loess Plateau, Robinia
pseudoacacia and Populus simonii as objects, , this paper studied the impact of sites (gully
tableland with good water supply and slopeland with low water supply) and tree age on leaf
hydraulic traits, leaf morpho-physiological traits and drought resistance aimed to elucidate
the related hydraulic mechanism of small dwarf tree-forming. The main results obtained
from this study were as follows:
(1) For both trees growing on tableland had larger leaf maximum hydraulic
conductance than those trees on slopeland, leaf maximum hydraulic conductance decreased
with the increase of tree age. Tableland-growing trees had higher leaf epidermal
conductance and PV curve parameters (including relative water content at turgor pressure
loss point RWCtlp, water potential at turgor pressure loss point ψtlp, and osmotic potential at
saturated water content ψsat) than those on slopeland; leaf epidermal conductance decreased
with the increase of tree age, and the PV curve parameters decreased to a different extent
for the two species. Leaf maximum hydraulic conductance was positively related with ψtlp,
suggesting there existed a tradeoff relationship between leaf flux capacity and
drought-resistance.
(2) The results indicated that for both species, trees growing on tableland had higher
hydraulic vulnerability (P50) and safety margin of water transport than those trees on
slopeland, but the vulnerability was almost the same with the increase of tree age. Safety
margin of water transport decreased with the increase of tree age. P50 was positively related
with some PV curve parameters, indicating for both trees at different age P50 was an
important drought-resistant trait.
(3) Black locust growing on the slopeland had smaller leaf area, higher specific leaf
mass and leaf thickness, lower whole-tree hydraulic conductance, decreased net
photosynthetic rate and stomatal conductance ,increased water use efficiency and N、P  nutrient content. Changes of leaf morpho-physiological traits of two species with tree age
showed the same trend as in drought habitat. Worse leaf water status and decreased
proportion of N in photosynthetic apparatus contributed to the decrease of photosynthetic
rate in old-aged trees. Site and tree age showed significant interaction for some important
leaf traits, indicating decreased photosynthetic area, raised leaf construction cost and lower
net photosynthetic rate are major reasons of forming small dwarf tree on the Loess Plateau.
Key Words:Robinia pseudoacacia; Populus simonii; site; tree age; leaf hydraulic traits;
leaf morph-physiological traits

Language中文
Document Type学位论文
Identifierhttp://ir.iswc.ac.cn/handle/361005/8924
Collection水保所知识产出(1956---)
Recommended Citation
GB/T 7714
李俊辉. 立地条件和树龄对刺槐和小叶杨叶水力 学特性的影响[D]. 北京. 中国科学院研究生院,2012.
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