White, Joseph Daniel.2017-06-052017-06-052017-052017-03-27May 2017http://hdl.handle.net/2104/10072An extant lycophyte, Huperzia lucidula, was studied to determine its response to higher atmospheric pressure and oxygen. This study answers two central questions: Do extant lycopsids respond to the atmospheric conditions of their ancestors? Is lycopsid gas exchange accurately modeled using current methods? By provides protocols for growing plants under the effect of various atmospheric conditions, this work demonstrates that atmospheric pressure is capable of effecting plants without changing the concentration of substrate active atmospheric gases and determines the effect of changed oxygen concentration on previously developed plants. Previous works have focused on the combined effect of pressure with increased CO₂ or on pressurizing plant products. This work furthers understanding of how ecosystem properties, such as canopy carbon assimilation, are likely heavily regulated by subsurface morphology. This research in terrestrial and synthetic atmospheres also suggests methods for growing plants more efficiently in water and light limited environments, potentially deep-space.application/pdfenClimate. Modeling. Morphology. Physiology. Lycophyte. Lycopsid. Oxygen. Pressure. Atmosphere.ThesisWorldwide accessAccess changed 8/24/222017-06-05