He J-S, Bazzaz F A
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138 USA.
New Phytol. 2003 Feb;157(2):229-239. doi: 10.1046/j.1469-8137.2003.00660.x.
• This study was conducted to determine whether elevated CO alters patterns of plant reproduction, and whether density affects population- and individual-level responses to elevated CO . • Phytolacca americana was grown in a glasshouse at three population densities under ambient and elevated CO environments, and harvested at both vegetative and seed mature stages. • CO did not affect the observed or estimated minimum size required for reproduction. At the population-level, elevated CO increased the total and above-ground biomass at both harvests. Density decreased both measurements at the second harvest. At the individual-level, elevated CO increased reproductive mass but decreased seed size, and the responses of reproductive allocation were density-dependent. Net photosynthesis at saturating light (P ) increased under elevated CO , but decreased with density, with a CO × density interaction. • hese results indicate that CO advances timing of flowering by changing growth rate rather than modifying minimum size required for reproduction, while density modifies the responses of reproductive allocations to elevated CO in P. americana .
• 本研究旨在确定二氧化碳浓度升高是否会改变植物繁殖模式，以及密度是否会影响种群和个体水平对二氧化碳浓度升高的响应。• 垂序商陆在温室中于三种种群密度下，分别在环境二氧化碳浓度和升高的二氧化碳浓度环境中生长，并在营养期和种子成熟期进行收获。• 二氧化碳浓度并未影响观察到的或估计的繁殖所需最小尺寸。在种群水平上，二氧化碳浓度升高在两次收获时均增加了总生物量和地上生物量。密度在第二次收获时降低了这两项测量值。在个体水平上，二氧化碳浓度升高增加了繁殖量但减小了种子大小，且繁殖分配的响应是密度依赖性的。饱和光强下的净光合速率（P）在二氧化碳浓度升高时增加，但随密度降低，存在二氧化碳浓度×密度的交互作用。• 这些结果表明，二氧化碳浓度升高通过改变生长速率而非改变繁殖所需最小尺寸来提前开花时间，而密度则改变了垂序商陆对二氧化碳浓度升高的繁殖分配响应。
