They’ve been growing plants in zero G for quite some time now and they expected to find that roots would grow aimlessly in all directions due to no gravity. But what the actually found was that the stems and leaves grow towards the light and that the roots grew away from the light. So its the light was the controlling mechanism on where the roots grew and not the gravity! This is good news as it means that we can grow plants in zero G. This will be critical for the journey to mars when we’ll need to grow food en route.
Few years back, researchers from the University of Florida, Gainesville, USA, grew two types of Arabidopsis thaliana cultivars – Wassilewskija (WS) and Columbia (Col-0) – on the International Space Station ISS to study the effect of zero gravity on plant growth. Interestingly, seeds germinated on the sprouted roots that behaved like they would on Earth—growing away from the seed. Its believed that major reason behind this growth is to seek nutrients and water in exactly the same pattern observed with gravity, other reasons could include moisture, nutrients, and light avoidance.