One of the things I had never thought about until last October, mid-way through a plant biology lecture, was the idea of sending plants to space. It seems to be a pretty crazy idea but by taking plants into a zero-gravity environment like space, we can compare them to how they grow on Earth and see if gravity really is important factor for plants.
The big question is: Do plants grow normally without gravity? The answer is they do. As you can see from the picture below, plants look like plants in space too. They must have some other way of knowing how to grow in the right directions. Plants in space also grow towards light and don’t need gravity to tell them which way is up!
Mizuna lettuce growing onboard the International Space Station. Souce: NASA
The Mizuna lettuce above, along with some other vegetables, were grown in 2010 in the International Space Station (ISS) and then frozen and sent back to Earth. Some of the vegetables were actually eaten by the crew onboard! The plants were analysed to see if they were normal despite being grown in strange conditions and how good they were to eat. Knowing the best way to grow plants in space will help to pick the best plants to make the long journey from Earth in the future.
What some root experiments in space look like. Source: NASA
As well as this research, the Plants in Space program, funded by the National Space Biomedical Research Institute, aims to give students the chance to design their own plant experiments to be carried out in space!
NASA sent some Brassica rapa seeds into space where they grew onboard the ISS to see how their roots grow without gravity. The astronauts followed instructions from the students and daily photos were taken of all the roots in the experiment. The students could then compare the photos with results of their own version of the experiments back on earth. These earth experiments were controls where the only difference was the presence of gravity. The results showed that the roots grew towards red light and away from blue, something that was impossible to know without them being at zero-gravity.
But why do we care what plants do in space?
Plants could actually prove to be the perfect companions for astronauts. One of the main goals of researching how plants grow in space is to try and create a garden to feed astronauts as they undertake longer and longer journeys away from the Earth. They could provide them with oxygen from photosynthesis, drinkable water and a source of food. At the moment, the International Space Station is not self-sufficient but with all this talk of going to Mars, they are going to need to improve this. Plants could be exactly what they are looking for!
For lots of extra details on all of these experiments, here is a video from NASA:
(Click the photos for links to the original articles on NASA’s website)
Plants and Prejudice 
this is really interesting, I never thought about whether gravity is necessary for plants. I always just assumed it was!
who thought plants could use sugar as weights to figure out the direction of gravitation 😉
they should have tried to grow pretty flowers too 😛
Perhaps it is due to a space constraint (ha.) which is the reason for the lack of flowers but definitely something for them to think about if they ever manage to take plants to Mars.