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Performance of Rapid Cycling Dwarf Arabidopsis Grown In a Lunar Light Regimen.  R.N. Bowman and G-S. Sun, Lockheed Martin Mission Services, M/S 236-5, NASA Ames Research Center, Moffett Field, CA 94035.

   As a precursor to future NASA missions to the moon, Mars and beyond, we have developed dwarf Arabidopsis thaliana lines suitable for plant experiments that can be performed within the constraints of spaceflight hardware. We now report on the performance of these lines under conditions that might be encountered in a lunar surface experiment including severely altered daylength, limited humidity regulation and constrained temperature control as might be present in lunar surface experiments. Plants were grown in incubators with 14 continuous earth-day lighting (lunar day) alternating with 14 continuous earth-days of darkness (lunar night), the worst-case regimen that might be encountered on the moon. All lunar days were maintained at 22°C. When lunar nights were maintained at 22°C, all plants died after the first lunar day/night cycle. By lowering the lunar night temperature to 10°C or 4°C, we were able to grow healthy normal Arabidopsis plants to full sexual maturity in four lunar day/night cycles. Plants grown with 4°C lunar nights produced viable seeds in 62 earth days from initial seed germination.

   The ability to grow healthy plants in a lunar light regimen is a prerequisite to lunar experiments intended to explore the effects of 1/6 g and a harsh lunar radiation environment on living organisms. By successfully growing plants in the worst-case lighting conditions that might be encountered on the moon, we are now prepared to perform lunar plant experiments in proposed “hitchhiker” hardware that might be included on future lunar rover platforms. The plant habitat portions of these platforms could utilize incident moon lighting for plant growth and minimal above-freezing temperatures when the rover is power-limited during lunar nights. The results of this experiment demonstrate proof of concept for seed-to-seed plant growth experiments under lunar conditions.