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seed PRODUCTION BY PLANTS GROWN IN A LUNAR THERMOPHOTOPERIOD. j. Blasiak and M.E. Musgrave. Department of Plant Science, University of Connecticut, Storrs, CT 06269.

   To establish an extra-terrestrial presence, it is necessary for organisms to not only survive, but reliably reproduce over multiple generations under non-earth-normal conditions.  The proposed long-term lunar expedition provides an ideal starting point for developing a sustainable life-support system for human habitation. While lack of atmosphere and thermal extremes make the surface of the moon inhospitable to life, sustained plant production could be achieved using incident light and minimal thermal regulation within a pressurized habitat.  A 708 hr photoperiod prevails on the moon except at the poles. These experiments were conducted to determine how compatible a range of horticultural crops and model plants would be with this regimen.  Flats of soil-less potting mix were seeded, watered, and placed in the dark at 3°C for 354 hr, followed by exposure to 354 hr of continuous light (300 mmol/m²/sec, PAR) at 22°C.  During the dark period, plants experienced short periods (<15 min total) of very low light (<0.5 mmol/m²/sec, PAR) during maintenance.  Onion (‘Long White Bunching’ and ‘Candy’), pea (‘Little Marvel’), radish (‘Early Scarlet Globe’), spinach (‘Winter Bloomsdale’), arugula (‘Agway’), lettuce (‘Black Seeded Simpson’ and ‘Polar Ice’), tah choy (‘Arctic Circle’), Rapid Cycling Brassica rapa (Crucifer Genetics Cooperative #1-33), Arabidopsis thaliana (‘Columbia’) and Draba verna were grown. All but the onion and lettuce had flowered by the end of the 4^th light period under the lunar regime.  B. rapa, A. thaliana and arugula, had produced mature, dry seeds by the end of 3 lunar cycles (84 Earth days).  Life cycles for these plants under a constant thermophotoperiod of 22°C range from 50-70 d, demonstrating that development proceeded during the 3°C dark periods.  The seeds produced in the lunar thermophotoperiod were 91% and 64% of the starting seeds’ weight for B. rapa and arugula respectively and both showed >80% germination.  Using incident light and minimal thermal input to support plant growth in a lunar setting can result in resource savings and pave the way for a sustainable lunar habitat that will serve as a model for further extra-terrestrial colonization.