Simulated Microgravity Effects on Plant Nutrition

Abstract

Future long-term spaceflight missions rely on bioregenerative systems which have the capacity to provide the required resources for crew survival. As suppliers of food and oxygen, higher plants are essential for these new systems. The adequate uptake of water and nutrients play a key role in the successful cultivation of higher plants in space. There are indications that under space conditions, plants might be inefficient in the uptake of nutrients, transport or distribution of these elements, which in turn affects plant growth and metabolism. The knowledge of potential effects of space environment and reduced gravity on plant nutrition is limited. Therefore, Arabidopsis thaliana (Col-0) plants were grown from seed to seedlings stage for five days under clinorotation (fast-rotating 2-D clinostat) in order to compare the nutrient concentration in shoots under altered and normal gravity conditions. Because of technical limitations, a protocol was developed for the reliable determination of different nutrients from small quantities of plant material and in part low concentration by means of ICP-OES, OES and spectrophotometry. The results indicate that the concentrations of boron and sulfur were significantly decreased under clinorotation, while the concentration of sodium was elevated, indicating that altered gravity conditions affect transpiration, oxygen availability in the medium, nutrient transporters or key enzymes involved in element assimilation pathways.