濒危物种灰叶胡杨不同发育阶段枝系构型特征研究

The Branching Architecture Characteristic of Endangered Species Populus Pruinosa in Different Developmental Stages

以灰叶胡杨这种非常重要的濒危的荒漠植物为研究对象,以不同胸径代表不同发育阶段的灰叶胡杨,通过对其枝系构成指标的测定与分析,探明了:1.随着发育阶段的成熟,分枝的级别增加,枝系构型的中部分枝较为丰富,下部分枝较为疏松,促进通风透光,提高空间利用率;分枝长度随分枝级别增加而变短;2.分枝率随胸径增大而增大;在相同胸径范围内,逐步分枝率差异显著或极显著,不同发育阶段枝倾角差异显著,胸径越小,枝倾角越大,分枝构型越为上冲,随胸径增加,枝倾角减小;分枝级别越高,分枝角度越小,构型越紧凑,上部分枝枝倾角较小构型相对平展;3.灰叶胡杨叶片长大于宽,近乎圆形,随着胸径变大,叶面积有所增加,叶片数也增多,作为枝上的构建单元也作为辅助参数构成了分枝格局的一部分,反映了其枝系构型的结构特点,对光照等能源的利用及适应策略。

The very important and endangered desert plant Populus pruinosa was chosen as material, with DBH represent different de- velopmental stages, the branching architecture characteristic was investigated. The result showed that, with the developmental stage, the branching level increased, branching pattern in the middle branches are rich, the lower branches was loose, which could promote the ventilation, improve space utilization rate, and the length of branch decreased with the increasing of branch level. The branched rate increased with the DBH increasing, in the same diameter range, the stepwise bifurcation ratio was significantly or very significantly different, at different developmental stages, the branch angle was significant difference, the smaller diameter, the larger the branch an- gle, the higher the level of branches. The Populus pruinosa leaves were longer than wide, and were almost circular, with the increasing of the chest diameter, the leaf area increased, the number of leaves was also increased, and as a construction unit, as well as the auxil- iary parameters forming part of a branching pattern, it reflected the features of the branching pattern, the light energy Source utilization and adaptation strategies.