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MICROGRAVITY EFFECTS ON WHEAT GROWTH AND PHOTOSYNTHESIS: PRELIMINARY RESULTS FROM PESTO EXPERIMENT.  G.W. Stutte, G.M. Monje, G.C. Goins, and D.C. Chapman.  Dynamac Corporation, Mail Code DYN-3, Kennedy Space Center, FL.

   The Photosynthesis Experiment Subsystem Testing and Operations (PESTO) experiment was conducted onboard the International Space Station (ISS) in the Biomass Production Chamber (BPS) during for 73 days during Increment IV.  Nine plant growth cycles (18 to 23 days in duration) were completed during this experiment.  Excellent germination (>97%) was obtained on each of six on orbit plantings.  Growth rates of germinated wheat of microgravity and ground plants were similar on each of the planting.  A total of over 300 plants were frozen on orbit for dry mass and chemical characterization.   Closed system and semi-closed system measurements of canopy level carbon exchange rates were obtained daily, and detailed characterization of CO₂ and light response curves were obtained at three stages of development for each cycle.  Preliminary analysis indicates that canopy level CER were similar between plants grown on ISS and on Earth under comparable environmental conditions.

 (This research was supported by grant from NASA Fundamental Biology Progroms (NCC10-0027)).

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