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Stress Response to Magnetic Levitation (Low-Gravity) and High Magnetic Fields in Transgenic Arabidopsis.   A.N. Morgan¹, J. Yowtak¹, R.J. Ferl³, J.S. Brooks², A.-L. Paul³, and M.W. Meisel¹. ¹Dept. of Physics and NHMFL, Univ. of Florida, Gainesville; ²Dept. of Physics and NHMFL, Florida State Univ., Tallahassee; and ³Dept. of Hort. Sci. and Biotech. Program, Univ. of Florida, Gainesville.

Genetically engineered Arabidopsis thaliana provides a means to examine the effects of low-gravity and strong magnetic fields at the cellular level. The plants are engineered with a transgene gene containing the Adh promoter and GUS reporter gene. The Adh gene is sensitive to a variety of environmental stresses and induces GUS expression in stressed tissues. GUS activity is evaluated qualitatively for cellular distribution by staining the plant with an appropriate substrate to produce a blue color in tissue regions where there are concentrations of the GUS enzyme. A quantitative measure of GUS activity in the plant tissue is obtained using spectrofluorometric assays. Arabidopsis plants were magnetically levitated in magnetic field gradients to simulate a milli-gravity     (» 10^-3g; g = 9.8 m/s²) environment. Control specimens were exposed to earth's gravity (i.e. 1 g) and 2.5 hours of a homogeneous magnetic field from 0 to 25 Tesla. High levels of GUS activity were found in both levitated plants and plants that experienced strong homogeneous magnetic fields. For the homogeneous field specimens, increased GUS activity is found above fields of 17 Tesla in both leaf and root tissue, with the GUS activity in the leaf tissue approaching the levels seen during hypoxic stress induction. Qualitative and quantitative data will be presented and the potential use of magnetic levitation as an earth-based low-gravity environment for staging preliminary experiments will be discussed.