[43]

Evaluating Growth characteristics and total Anthocyanin Content in Three Cultivars of Hydroponically-Grown red romaine-type Lettuce (Lactuca sativa l.) in Response to Three Lighting Intensities.  C. E. Yunker1 and J. T. Richards2.  1The Schreyer Honors College at the Pennsylvania State University, University Park, PA 2Dynamac Corporation, Kennedy Space Center, FL.

   The presence of an edible space garden on long duration space missions can have physiological and potential psychological benefits for the crew.  Due to the power limitations and air cleansing systems in a spacecraft, space-grown plants would be exposed to less than optimal growing conditions, such as low lighting levels and high CO2 concentrations.  Three cultivars of red romaine-type lettuce (Outredgeous, Eruption, and Red Sails) were grown hydroponically under three different light intensities (8.6, 17.2, and 26 mol m-2 d-1) to determine their growth characteristics under ISS environmental baseline conditions for possible inclusion into the ALS candidate crop list.  In addition, as potential criteria for selection of a cultivar, total anthocyanin content of each lettuce cultivar grown under the three lighting intensities was determined.  Anthocyanins are important in a crew's diet as they are strongly correlated with antioxidant, or free radical scavenging, capacity.  Red Sails had the highest edible fresh weight at all light intensities, but its stature may not be conducive for an "open" mixed salad production system, as it may shade shorter or slower growing plants.  Both Eruption and Outredgeous had similar anthocyanin content over all light intensities, and levels were nearly three-fold higher than Red Sails.  From these results, Outredgeous may have the optimal characteristics best suited for the proposed "open" space garden production unit.(Supported by NASA's 2004 Spaceflight and Life Sciences Training Program)