Vascular anatomy changes in tomato stems grown under simulated microgravity

Gravity is a pervasive cue that directs the growth and development of living systems on Earth and in space environments. However, little is understood about how gravity shapes living systems. This study reports a set of large-scale 2D clinostats that support the growth of plants beyond the seedling stage. Using these clinostats, five replicate experiments containing two tomato cultivars were grown under upright control and simulated microgravity conditions. We showed a variable response to simulated microgravity that was impacted by replicate experiment, but not cultivar. This variable response showed an increase in shoot and root traits under simulated microgravity in some replicate experiments and a reduction in shoot and root traits under simulated microgravity in other replicate experiments. We additionally report a cultivar-specific change in stem vascular anatomy in response to simulated microgravity, which was not impacted by replicate experiment. This work demonstrates the potential to promote plant growth under simulated microgravity and reports a novel modulation of vascular anatomy in response to simulated microgravity.