ASGSB 1999 Annual Meeting Abstracts

QUANTIFICATION OF EPIPHYTIC BACTERIAL POPULATIONS ON THE PHYLLOSPHERE OF SPINACH PLANTS GROWN UNDER EXPERIMENTAL LIGHTING CONDITIONS. D.M. Salvay¹, J.L. Adams², J.L. Garland², G.D. Goins². ¹Department of Biology and Biomedical Sciences, Washington University, St. Louis, Missouri; ²Dynamac Corporation, Kennedy Space Center, Florida.

Due to the limited capacity and enormous cost of carrying, transporting, and restocking items in-flight, long-term space missions will require the implementation of advanced life support systems to provide food to astronaut crews. Because of space and energy constraints, systems used to grow food must be very efficient and require a minimal amount of energy. One such candidate system utilizes light emitting diodes (LEDs) to provide photosynthetically active radiation (PAR) to growing plants. It is currently unknown how such lighting systems will affect epiphytic bacterial populations on the phyllosphere of salad crops. Because salad crops are not cooked, thereby killing any bacteria, prior to being eaten, it is important to understand whether such lighting systems will affect epiphytic bacterial populations of possibly pathogenic microorganisms. In this baseline study, we examined how total epiphytic bacterial concentrations varied over the life-cycle of spinach plants and whether the use of lighting systems that utilize light emitting diodes (LEDs) affected these population concentrations. Preliminary data indicate that there are non-significant differences in bacterial concentration between the various lighting treatments based on CTCs and AOs. Subsequent studies will investigate the specific types of microorganisms present and evaluate their relative pathogenicity.

(Supported by NASA through the Space Life Sciences Training Program.)

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