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Photosynthesis

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Effects Of Elevated Temperature And Elevated Co2 On Leaf Carbon Fluxes In Boreal Conifers: Lab And Field Studies, Mirindi Eric Dusenge Oct 2019

Effects Of Elevated Temperature And Elevated Co2 On Leaf Carbon Fluxes In Boreal Conifers: Lab And Field Studies, Mirindi Eric Dusenge

Electronic Thesis and Dissertation Repository

Rising CO2 may warm northern latitudes up to 10 °C by the end of the century. However, responses of plant physiological processes (such as photosynthesis and respiration) and growth to climate change remain uncertain. Seedlings and mature trees of tamarack (a deciduous species) and black spruce (an evergreen species), North America dominant conifers, were exposed to combined warming (up to +9 ˚C) and elevated CO2 (up to +300 ppm). In seedlings, stomatal conductance (gs) tended to increase with warming in tamarack seedlings, while gsdeclined with warming in spruce. In both species, CO2 had …


Carbon And Nitrogen Dynamics In Plants Grown At Low Co2 Conditions Of The Past, Andre Galvao Duarte Sep 2019

Carbon And Nitrogen Dynamics In Plants Grown At Low Co2 Conditions Of The Past, Andre Galvao Duarte

Electronic Thesis and Dissertation Repository

For most of the recent evolutionary history of plants, atmospheric CO2 concentrations have been far below modern values. However, little is known about how plants grown in a low CO2 environment balance their carbon demand for growth while meeting their requirement for nitrogen acquisition, the establishment of mycorrhizal fungal associations, and the production of defense compounds. Here, I investigated how low CO2 affects Elymus canadensis and Picea mariana by comparing their growth at low and current CO2 concentrations. I found that reduced N availability exacerbated low CO2 effects on growth, and reduced stomatal index and …


Effects Of Elevated Temperature, Elevated Co2 And Photoperiod On Conifer Carbon Fluxes, Joseph R. Stinziano Apr 2018

Effects Of Elevated Temperature, Elevated Co2 And Photoperiod On Conifer Carbon Fluxes, Joseph R. Stinziano

Electronic Thesis and Dissertation Repository

Increasing temperatures due to rising atmospheric CO2 concentrations will have direct effects on plant physiology, specifically photosynthetic carbon uptake. Changes in photosynthetic carbon uptake will alter feedbacks between vegetation and atmospheric CO2, and changes in forest carbon dynamics will be important in determining whether vegetation amplifies or attenuates the effects of anthropogenic CO2 emissions on climate. Coniferous trees, which are a large component of the boreal forest, are understudied in relation to thermal acclimation of photosynthesis and temperature effects on growth. In the present work, I assess the impact of rising temperatures on carbon fluxes in …