Image: Microscopic statoliths in seedling grown in space

January 20, 2016
Credit: ESA/Université Blaise Pascal

How do plants know which way is up? This might seem like an obvious question, but how exactly does a plant know which way to grow its roots and which way to grow towards the Sun?

Understanding the deeper mechanisms that cause a plant to grow in a particular direction has far-reaching possibilities for agriculture – as well as for astronauts who want to enjoy fresh vegetables on a long space mission.

This image shows a lentil seedling root that grew on the International Space Station before being preserved in resin and cut along its length for analysis.

The purple dots are starch-filled statoliths that usually drop towards gravity, but this plant grew in space and the statoliths are floating in the middle of their cells.

In addition to these cross-sections, almost 2500 pictures charted the 768 seeds growing over 31 hours in microgravity and hypergravity in the European Modular Cultivation System on ESA's Columbus space laboratory.

"This research could not be done on Earth because gravity would get in the way of our readings," explains Francois Bizet, who is analysing the images as part of a post-doctoral programme in France's CNES space agency. Regular updates are posted on the experiment's blog.

The results from the Gravi-2 experiment are showing what could be responsible for sending growth-direction signals to the plant's cells. Gravi-2 continued an earlier experiment that examined the limits of how plants perceive gravity, with this second experiment looking in particular at how calcium is used by plants to regulate growth.

On Earth, soluble calcium spreads to plant roots and is considered an important part of plant growth because they respond to environmental signals. Gravi-2 will also look at gene expression to highlight how intracellular calcium could be a second messenger for perceiving gravity.

"We need to grow the seeds in different environments to compare results and work out which change is due to ," says Valérie Legué from the Université Blaise Pascal in Clermont-Ferrand, France.

"Understanding is the first step to adapting crops for more productive agriculture. If we could grow lentils vertically, for example, farmers could drastically increase crop yield per square metre."

Explore further: ESA's weightless plants fly on a Dragon

Related Stories

ESA's weightless plants fly on a Dragon

April 23, 2014

(Phys.org) —It is a race against time for ESA's Gravi-2 experiment following launch last Friday on the Dragon space ferry. Stowed in Dragon's cargo are lentil seeds that will be nurtured into life on the International Space ...

Plants use sixth sense for growth aboard the space station

April 6, 2015

Although it is arguable as to whether plants have all five human senses – sight, scent, hearing, taste and touch – they do have a unique sense of gravity, which is being tested in space. Researchers with the Japan Aerospace ...

Image: Arabidopsis thaliana shoots en route to ISS

April 15, 2015

This microscope image taken at 40 times magnification shows the individual cells that make up the root of an Arabidopsis thaliana plant. Next month, 200 five-day-old shoots will fly a roller-coaster ride on an aircraft to ...

Gardening in Space with HydroTropi

January 19, 2011

(PhysOrg.com) -- Plants are fundamental to life on Earth, converting light and carbon dioxide into food and oxygen. Plant growth may be an important part of human survival in exploring space, as well. Gardening in space has ...

Space Station study seeks how plants sense 'up' and 'down'

April 30, 2014

On Earth, we take for granted that a plant grows up and its roots grow down. In space, however, this seemingly predictable formula is upended. How do plants sense "up" and "down" where those relative positions don't exist?

What happens to plant growth when you remove gravity?

December 7, 2012

It is well known that plant growth patterns are influenced by a variety of stimuli, gravity being one amongst many. On Earth plant roots exhibit characteristic behaviours called 'waving' and 'skewing', which were thought ...

Recommended for you

SpaceX to launch classified US govt payload Sunday

April 29, 2017

SpaceX on Sunday is scheduled to make its first military launch, with a classified payload for the National Reconnaissance Office, which makes and operates spy satellites for the United States.

Is dark matter 'fuzzy'?

April 28, 2017

Astronomers have used data from NASA's Chandra X-ray Observatory to study the properties of dark matter, the mysterious, invisible substance that makes up a majority of matter in the universe. The study, which involves 13 ...

Hubble's bright shining lizard star

April 28, 2017

In space, being outshone is an occupational hazard. This NASA/ESA Hubble Space Telescope image captures a galaxy named NGC 7250. Despite being remarkable in its own right—it has bright bursts of star formation and recorded ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.