Subsequent research went on to investigate the effect of low gravity on plants at the organismic, cellular, and subcellular levels. At the organismic level, for example, a variety of species, including pine, oat, mung bean, lettuce, cress, and "Arabidopsis thaliana", showed decreased seedling, root, and shoot growth in low gravity, whereas lettuce grown on Cosmos showed the opposite effect of growth in space (Halstead and Scott 1990). Mineral uptake seems also to be affected in plants grown in space. For example, peas grown in space exhibited increased levels of phosphorus and potassium and decreased levels of the divalent cations calcium, magnesium, manganese, zinc, and iron (Halstead and Scott 1990).