About the Cover
On the Cover: The glowing trichomes in this Arabidopsis plant are expressing Adh/GFP in response to an atmospheric environment of 10 kPa, roughly one-tenth of Earth atmospheric pressure at sea level. Paul et al. (pp. 215-223) have used GFP reporter genes and microarrays to characterize changes in Arabidopsis gene expression in hypobaric environments. Arabidopsis responds to hypobaria with the significant differential expression of over 200 genes. Less than half of these genes are similarly affected by hypoxia, indicating that the response to hypobaria is more complex than an adaptation to the reduced partial pressure of oxygen intrinsic to hypobaric environments. The gene expression patterns unique to hypobaria suggest that water movement is a paramount issue for plants at low pressure and that ABA signaling plays a central role in the adaptive response. Mars, as imaged by the Hubble telescope, looms in the background to represent NASA's interest in hypobaric plant physiology. Bioregenerative life support systems envisioned for long term missions, including those to Mars, seek to maximize production within structures designed to minimize mass, resource consumption and pressure differentials. Advancements on these engineering goals can be made through the utilization of reduced atmospheric pressures in greenhouses and other plant culture environments. Mars is an especially appropriate and current extraterrestrial focal point since the Mars Exploration Rovers Spirit and Opportunity will begin their exploration of the Martian surface this month. Cover design by Anna-Lisa Paul and Robert Ferl.
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Copyright © 2004 by the American Society of Plant Biologists
