沙柳(Salix psammophila)丛生枝生物量最优分配与异速生长

摘要： 茎叶生物量分配的权衡关系是植物生活史研究的重要内容。以毛乌素沙地南缘的优势灌木沙柳(Salix psammophila)为对象,用生物量分配份数的方法分析了沙柳丛生枝尺度上茎、小枝、叶生物量分配与个体大小的依赖关系,并用标准主轴回归(SMA)检验茎、小枝、叶生物量的异速生长关系。结果表明:(1)随着沙柳丛生枝的增大,茎、小枝、叶各构件生物量积累明显,基径比枝长能更好地反映生物量随个体大小的变化规律;丛生枝茎、小枝、叶和总生物量随基径变化的幂函数分别为y=0.1861x2.2950、y=0.0194x2.9794、y=0.0875x2.1421和y=0.1863x2.5454。(2)随着沙柳丛生枝个体的增大,总资源中分配到茎和叶的份数下降,分配到枝的份数增加;基径能更好地解释茎和小枝生物量分配份数的变化,枝长能更好地反映叶生物量分配份数的变化。(3)沙柳丛生枝茎、小枝、叶生物量相互间均存在显著的异速生长关系,异速指数αT-S、αL-S和αL-T分别为1.557、1.087和0.6916,随个体大小的变化,小枝生物量的变化速度最快,叶生物量的变化次之,茎生物量的变化速度最慢。最优分配理论和异速生长分配理论能互为补充,较好地解释沙柳丛生枝构件的生物量权衡关系。

关键词: 沙柳(Salix psammophila), 生物量分配, 个体大小, 异速生长, 毛乌素沙地

Abstract: Data on tree biomass are essential for evaluating carbon sequestration cycling, plant adaptations to the environment and also for studying impacts of silvicultural practices on forest productivity. We determined biomass accumulation and allometric relationships in the partitioning of above ground biomass between stems, twig, and leaves in Salix psammophila, a sandy shrub, it not only protects environment, but also has economic value. The biomass allocation patterns were studied by fitting allometric functions in biomass partitioning between leaves (ML), stems (MS) and twigs (MT). The results showed that: (1) Biomass accumulation varied with branch basal diameter (BBD) and branch lengths (BL) increased, and BBD has a higher coefficient of determination in the form of power functions, and the allometric biomass equations for stems, twigs, leaves and of all were y=0.1861x2.2950, y=0.0194x2.9794, y=0.0875x2.1421 and y=0.1863x2.5454, respectively. (2) The number of the resources allocated to stem, twigs and leaves were changed with branches growing. There showed the power functions better with BBD than BL which the percentages of resource allocated to stem and leaves, and the percentages of twigs biomass to total biomass was better with BL. (3)There existed an allometric relationship between the MS, MT and ML, with the standardized major axis slopes were 1.557 (αT-S), 1.087 (αL-S) and 0.6916 (αL-T), respectively. The twigs have the highest values which increasing with the branches growing, and the stem has the lowest values of that. Therefore, our results indicated that the optimal partitioning theory and metabolic scaling theory complement each other, and it can explain the biomass changed and the scaling relationship for stem, twigs and leaves in S. psammophila branches.

Key words: Salix psammophila, biomass allocation, body size, allometric growth, Mu Us Sandy Land

中图分类号: 

Q945.3

Q948.1

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