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Analysis of canopy structure of multi-species plant communities

多物种植物群落冠层结构分析

基本信息

批准号：
06454007
负责人：
HIROSE Tadaki
金额：
$ 4.35万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

A plant communty consists of a range of species different in plant height. Tall dominant species occupying upper layrs in the canopy receive a large fraction of photon flux density, while small subordinate species occupying lower layrs receive small fractions of available photons. Tall species, however, invest relatively more biomass to supporting tissues to position their leaves high in the canopy. Thus photon absorption per unit aboveground biomass is similar between tall dominant and small subordinate species. Through the two-year study, we found : (1) In the Miscanthus sinensis stand at Kawatabi, photon absorption per unit aboveground biomass of subordinate species such as Lysimachia japonica was high early in the growing season, while that of dominant Miscanthus sinensis was high late in the growing season. This enables subordinate species to coexist with dominant Miscanthus sinensis. (2) Mixed stands of rice (C3) and millet (C4) were established in a greenhouse and competition be … More tween these species was analyzed. Although millet germinating later than rice, its growth rate was larger than rice plants. Rice reduced the growth of millet by 5%, while millet reduced the growth rate of rice up to 30%. (3) We developed a model to estimate photosynthesis of individuals in a dense stand and analyzed factors involved in the development of size hierarchy. Tall dominant plants had larger photon absorption per unit aboveground biomass and larger photosynthetic rates per unit absorbed photon flux density than suppressed plants, intensiflying the size hierarchy of the stand. (4) A model was made to analyze the effect on photosynthetic capacity of different nitrogen partitioning among photosynthetic proteins. The optimal partitioning, depending on light conditions, lead to up to 20% increase in photosynthetic efficiency. (5) We compared protein partitioning between sun (Chenopodium album) and shade (Alocasia macrorrhiza) plants. Both species had protein partitioning close to the theoretical optimum. Less

植物群落由一系列不同植物高度的物种组成。占据冠层上层的高优势种接收到大部分的光子通量密度，而占据下层的小从属种接收到少量的有效光子。然而，高大的物种投入了相对更多的生物量来支持组织，使它们的叶子在冠层中处于高位。因此，每单位地上生物量的光子吸收在高优势种和小从属种之间是相似的。通过2年的研究，我们发现：(1)川边芒草林分单位地上生物量的光子吸收在生长季前期以小野菜（Lysimachia japonica）为主，而优势芒草在生长季后期以高光子吸收为主。这使得从属种与优势种芒草共存。(2)在温室内建立了水稻（C3）和谷子（C4）混交林，并分析了两种间的竞争情况。谷子虽然发芽晚于水稻，但其生长速度大于水稻植株。水稻使谷子的生长速率降低了5%，而谷子使水稻的生长速率降低了30%。(3)建立了密集林分个体光合作用估算模型，分析了影响林分大小等级发展的因素。高优势株的单位地上生物量光子吸收和单位吸收光子通量密度的光合速率均大于受抑制株，加剧了林分的大小等级。(4)建立了不同光合蛋白间氮分配对光合能力的影响模型。根据光照条件进行最佳分配，可使光合效率提高20%。(5)比较了日光植物（Chenopodium album）和遮荫植物（Alocasia macrorrhiza）的蛋白质分配。两个物种的蛋白质分配都接近理论最佳。少