Just read What's the effect of oxygen deficit on plants? ; and wondered whether the opposite would have any effect on a plant.
That is to say, if a potted plant were placed under a bell-jar and the air within replaced by pure oxygen would the plant starve? If the environment/soil were loosely radioactive, would it make a difference?
As hinted in other answers, the key problem with a pure oxygen environment would be the inability to photosynthesise caused by the absence of carbon dioxide.
The overall equation for photosynthesis (the process in which energy from the sun is harnessed to fix inorganic carbon dioxide into organic molecules that are of use to the plant) is:
The carbon dioxide required for photosynthesis is obtained from the atmosphere by diffusion through stomata on the leaves. Therefore if the atmosphere contains no carbon dioxide (i.e. in the scenario you suggest) photosynthesis would not progress, meaning glucose used by the plant in respiration would not be replaced.
This would eventually lead to the cessation of cellular respiration due to a lack of reactant. This would cause the plant to die.
Ask yourself, where would the plant take the carbon for construction of all kind of molecules, most important the cell membrane and cell wall of newly divided cells. Plants do not eat! So they have to get their carbon from somewhere else.
Keep in mind, there is a chance that a growing plant in a sealed environment with pure oxygen WOULD SURVIVE because of the carbon dioxide discharge of aerobic bacteria in the soil. Consider that by the time a seed would sprout, the soil bacteria would have already had days to a week to metabolize CO2 as a waste product. This question depends on manifold variables (chiefest of which dealing with the environment and especially the size of the biome).
