Dissertation Research: Ecology and Evolution of Aquatic Sphagna: Functional Morphology, Physiology and Phylogeny

大的边界层和缓慢的二氧化氮在水中的扩散速率会限制水生和饱和植物的生长和光合作用。尽管研究人员试图描述促进水中碳吸收的生理机制，但很少有工作关注形态在减少水生栖息地边界层阻力中的作用。苔藓属Sphagnum的物种表现出形态变异，初步研究表明这种变异与沿水梯度的位置有关。因此，该属可作为研究其形态、边界层特性与生理生态关系的模式系统。此外，由于该属在分类学上得到了很好的研究，系统发育可以得到发展，现代比较生物学方法可以用来测试适应的假设。本研究的主要目的是：1)确定泥炭属植物形态与生境的相关程度；2)测量植物沿水梯度的边界层电导，并描述其与形态的关系；3)在淹没CO2水平下，边界层电导的差异导致了非水生藻的碳限制；4)利用构建的系统发育的历史证据来检验功能性状是否为适应性。

Large boundary layers and slow diffusion rates of dioxide in water can lead to limitations in growth and photosynthesis of aquatic and saturated plants. Although investigators have sought to characterize the physiological mechanisms that facilitate carbon uptake in water, little work has focused on the role of morphology in reducing boundary layer resistances in aquatic habitats. Species in the moss genus Sphagnum exhibit morphological variation that preliminary studies indicate is correlated with position along the water gradient. Thus, the genus can be used as a model system to investigate the relationship among morphology, boundary layer properties and physiological ecology. Also, because the genus is taxonomically well studied phylogeny can be developed and modern methods of comparative biology used to test hypotheses of adaptation. The major goals of this proposed study are as follows: 1) to determine the extent that morphology and habitat are correlated in Sphagnum; 2) to measure boundary layer conductance for plants along the water gradient and describe its relationships to morphology; 3) to demonstrate that differences in boundary layer conductance lead to carbon limitations for non-aquatic Sphagnum at submerged CO2 levels; and 4) to test whether functional characters are adaptations using historical evidence from a constructed phylogeny.