Designing Experiments for Direct Measurement of Wheat Photosynthesis in Microgravity

Procedures were developed for a future experiment to measure wheat (Triticum aestivum L.) photosynthesis in microgravity. Specific attention was given to growing and maintaining vigorous wheat plants relative to the challenging conditions predicted in microgravity. These ground-based tests included comparisons of different rooting media, media, wicking materials, and nutrient delivery system pressures. To facilitate seed germination in microgravity, several clinostat tests were conducted to characterize the importance of initial seed orientation. Following establishment of a vigorous crop canopy, photosynthesis rates were measured and found to be affected by mutual plant shading within the growth chambers.