不同生境对雅安市老板山水麻枝叶构件特征的影响

为探究植物（种群）生存及其对环境的适应对策和进化机制，以四川省雅安市老板山林内、林缘、沟边丛生以及林内单株水麻Debregeasia orientalis为研究对象，对其分枝数、分枝长度、分枝角度、枝径比、逐级分枝率以及叶片数、叶面积等构件特征进行调查分析。结果表明:①不同生境下，水麻分枝数以一级枝为主，沟边丛生水麻分枝长度优于其他生境，但无三四级枝生长，其分枝角度整体表现为收敛型，空间拓展能力较其他生境强；②同一生境下，二三级枝枝径比（R_BD3:2）最大，三四级枝逐级分枝率（S_BR3:4） < 一二级枝逐级分枝率（S_BR1:2） < 二三级枝枝逐级分枝率（S_BR2:3），二三级枝之间水分、养分运输效率高，分枝能力最强；③叶片数与分枝数变化规律一致，林缘丛生水麻叶片数最多，其叶面积与沟边丛生都大于其他生境，同一生境中，叶面积二级枝>一级枝>三级枝；④林缘生境更适合水麻聚集生长，沟边丛生水麻护坡、固土效果明显。表明不同生境水麻对光照、空间等环境条件响应不同，可采取措施以最大限度获取生境资源，更好地发挥水土保持功能。

Effect of different habitats on the branch and leaf module characteristics of Debregeasia orientalis in Laoban Mountain,Ya'an,Sichuan

By analyzing the branch and leaf module characteristics, including branch number, branch length, branch angle, the ratio of branch diameter, branch ratio, leaf number and area of Debregeasia orientalis from the forest plant, forest edge cluster, river bank cluster and forest cluster in Laoban Mountain, Ya'an, the research tried to understood mechanism how the plant (population) survived and adapted to environment. The results showed that:(1) Under different habitats, the first class branch of D. orientalis had the largest number of branches. The branch lengths of D. orientalis in river bank cluster were higher than those in other habitats and the branch angles were small, forming a convergence and having a great space expansion capacity; but it had no third and fourth class branch. (2) The R_BD3:2 was bigger and the branch ratio showed S_BR3:4 < S_BR1:2 < S_BR2:3 under the same habitat. They indicated that the transportation of moisture and nutrient as well as the branch capacity between the second and third class branches were higher. (3) Leaf numbers changed with the branch numbers. The D. orientalis in forest edge had a lot of leaves, and their areas were larger than those in other habitats as well as river bank. The leaf areas showed the second class branch > the first class branch > the third class branch. (4) Forest edge cluster was more suitable for Debregeasia orientalis having an aggregation growth and the D. orientalis in river bank had an obvious effect on slope protection and soil fixation. It indicates that D. orientalis in different habitats has different response to environmental conditions including light as well as space, and we can take measures to obtain the maximum habitat resources, play better functions of soil and water conservation.