Analysis of Plant Water Relations Under Variable Pressure: Technical Challenges

Future space exploration will require advanced life support (ALS) systems capable of in situ resource recycling. Hypobaric, bioregenerative life support systems have been proposed to address this requirement. The need to explore the limits of plant tolerance to hypobaric conditions is clear, however, research has been limited due to the difficulties and costs associated with this field. The Controlled Environment Systems Research Facility (CESRF), at the University of Guelph, Canada, has been designed to address the issues surrounding plant production under reduced pressure conditions. The measurement of plant physiological responses to hypobaric conditions is the subject of this study. Measurements of whole plant water relations, in terms of transpiration and plant water potential, are the ultimate goal. This phase of the work includes development and testing of the variable pressure plant growth chamber, and calibration of the in situ stem psychrometer for measuring plant water potential.