Space Update: Plants Don’t Seem to Mind Zero Gravity

December 12, 2012

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How does zero gravity affect plants? The answer. It doesn’t. The implications of this discovery are extraordinary. It means we can farm in space knowing that space-grown plants will pretty much grow like they do here on Earth.

How do we know this? A research study published in BMC Plant Biology this month shows that in an on board experiment at the International Space Station (ISS), a plant growth habitat was continuously monitored to track growth. This included constant photographic surveillance over a period of several days. What the plants showed us is that roots grow in the opposite direction of the principal light source just as they do here on Earth. It’s not gravity, therefore, that makes plants shoot roots into the soil and branches into the air. It’s their phototropic response that is the determiner. Plants respond to light.

plants in space3 — Whether grown on Earth (see the control image in the upper slide) or grown in space (the lower image), root development responds to the phototropic effect rather than gravity although roots tend to wander more in the absence of gravity. Source: BMC Plant Biology

For long duration human space flight the results of this experiment have significant implications. Ultimately, the long-term success of human spaceflight requires that we create self-sustaining ecosystems on board space habitats. Otherwise all human exploration in space will require us to carry not only the fuel necessary for flight but all consumables as well. With experiments like this we are examining the possibility of being able to grow our food in space. Will the technology we employ be much different from that we currently are deploying for vertical urban farms? It doesn’t appear to be much different at all which is very encouraging.

Plants in Space — The experiment on board the ISS involved Arabidopsis plants (a relative of the cabbage) grown within a specialized plant growth habitat monitored by cameras that continuously captured images of the plants as they germinated and grew. A comparable ground-based system was maintained at the Orbital Environment Simulator at Kennedy Space Center. The results of the plant growth at the two were compared. Source: BMC Plant Biology

The next step is to begin experiments on the International Space Station and here on Earth to further develop closed ecosystems that are self-sustaining. Last week I wrote about efforts by China to develop such technology. NASA, too, through on board experiments like the one reported here, are developing the expertise that will give humanity the means to thrive independently whether in low-Earth orbit, Deep Space, or on the Moon or Mars.

You can watch the time-lapsed imagery here.