Would a regular potted plant still grow upward (vertically) if it was in space? Why/why not?



Let’s assume the plant was sent into space in a comfy space shuttle with sufficient nutrients, gases, water, artificial light etc. but there is no gravity for the plant to grow against. Would geotropism still exist?

Edit: In the absence of gravity, which direction would the plant grow in? Eg. would it sprawl along the surface it is rooted to?

In: Biology

In the microgravity environment of low earth orbit there’s no way for a plant to know which way is up, so no. It’s not even clear what you mean by “upward (vertically)” though I guess you mean the direction away from the centre of the earth. Spacecraft don’t necessarily orient themselves so that the natural “up” for the vehicle matches this direction.

The orbital period in low earth orbit is around 100 minutes so having spacecraft “up” match earth “up” requires the vehicle to rotate at this same speed. Rotation like this is called “orbit rate attitude” and it helps with keeping radio antennae pointing towards the ground, but it’s not always done with spacecraft “up” away from the earth.

As long as there’s a gravity field, geotropism would exist, just maybe not in the amount it does here on Earth surface. If you’re in earth orbit, you still have gravity, but because the room (spaceship) is also moving in orbit, you fall at the same rate that gravity pulls on you.

If you were in deep space between galaxies, then you would indeed have a minimal net gravity direction.

With the plants we’ve grown in space so far, the direction of the roots orients the rest of the plant, and since the roots kinda have to grow into the soil the plant grows out more or less like it would on earth, albeit sometimes a bit slanted over as if they were on a hill.

Source: Worked with some of the folks that designed their irrigation system while I was working on designing a much less impressive consumer-grade gardening system in college.

Edit: Right now they’re growing lettuce in space, it’s possible that other more stem and vine type plants could be different, but we’re still doing baby steps.

I was under the impression that it would grow in the direction of the light source. Is that not necessarily the case?