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Optimizing the Growth Conditions of Arabidopsis thaliana from Seed-to-Seed in the EMCS on ISS. * A.-I. Kittang, B.G., Solheim, H. Svare, G. Rakvaag, A. Johannes, T.-H. Iversen.The PlantBio Center, Dep. of Biology, NTNU, Trondheim, Norway*Correspondence: Ann-Iren.Kittang@bio.ntnu.no

   In the MULTIGEN-1 experiment the model plant, Arabidopsis thaliana, will be grown from seed-to-seed in the European Modular Cultivation System (EMCS) on the ISS. The experiment is planned to be launched on flight 13A.1 (currently scheduled for June 11, 2007) and will be carried out in Increment 15 as the first long duration experiment in EMCS. The facility is commissioned during Europe’s first long-duration mission to the ISS (“Astrolab”), which began with flight STS 121. By monitoring the plants using the EMCS cameras, a comparative study of plants grown on a static centrifuge (microgravity) and on a rotating centrifuge (1xg) is performed. The scientific objective is to obtain basic knowledge about the growth patterns and the development of Arabidopsis thaliana in the microgravity environment. 

   The plants are supplied with nutrients and water during the whole life cycle via a Plant Cultivation Chamber (PCC). The PCCs monitor the relative humidity in the growth media and supply water automatically. The flowerpots of the PCCs are filled with zeolite that is enriched with nutrients. A poly-propylene-felt is placed on top of the zeolite to support in the seed germination phase. The EMCS water reservoirs supply the water to the PCC. The same reservoir is also used to obtain the requested relative humidity in the atmosphere and for this reason water economy is important. Another parameter that has to be considered in the same context is the air flow, which if running continuously at the nominal rates of EMCS, has a drying effect on the seedlings. Prevention of this effect and optimisation of growth media will be discussed in this presentation. Furthermore testing during the integrating phase of MULTIGEN-1 into the EMCS using the Ground Models is outlined from an investigator’s point of view.