Physiological Responses of Lettuce ( <italic>Lactuca sativa</italic> ) to Reduced Atmospheric Pressure

Mars is likely the best candidate for future planetary exploration however the Martian atmosphere is at a pressure of ~0.6 kPa. This extremely low pressure demands that plant growth structures be isolated from the ambient environment. While it is clear that it is desirable to predict the contributions that plants will make to bioregenerative life support systems at reduced atmospheric pressures, research has been limited. This study examines carbon exchange and evapotranspiration in order to establish a baseline that will aid in the development of an atmospheric composition that allows for reduced pressure plant growth without compromising the plant production yields required for human life support.