Can sending seeds to space prepare them for more stressful growing conditions?
How does six months on the International Space Station affect a seed’s ability to grow and can it ‘remember’ its time in outer space?
Experiments have already shown that seeds exposed to cosmic radiation do not grow as well as they normally would but UWE Bristol postgraduate researcher Nicol Caplin now wants to test the seeds’ ‘memory’ of their time orbiting the earth. By re-exposing them to radiation, she hopes to find out whether the seeds developed mechanisms during their time in space that prepare them to grow better in stressful conditions.
In 2015 the European Space Agency (ESA), in partnership with the Royal Horticultural Society (RHS), sent a shipment of rocket (E. sativa) seeds on the Soyuz 4SS spacecraft to the International Space Station. British ESA astronaut Tim Peake took care of the seed packages for the six-month stay, during which they would experience zero gravity and a dose of cosmic radiation.
“Cosmic radiation has the potential to affect seeds because its rays are very energetic, passing through the seeds or depositing energy inside them, even though they are dormant,” says Nicol.
The seeds were initially distributed to over 8,000 schools across the UK and handed out to pupils.
The aim was to grow the seeds and compare them to a batch of control seeds that had remained on Earth.
Biomathematics and Statistics Scotland (BioSS) analysed the data from the schools and found the seeds that had been in space had not grown as successfully as the control seeds. This news was made public by the RHS School Gardening organisation, who claimed that the earlier prediction that the seeds would be damaged by cosmic radiation was proven.
Nicol, a postgraduate research student in the Department of Health and Applied Sciences, obtained a sample of seeds from the experiment. These are now growing in her lab under controlled conditions, where light, temperature and humidity are highly regulated. She aims to find out whether re-exposing the rocket seeds to radiation, at levels that should not have detrimental effects to plants, actually makes it easier for them to grow.
“Plants are believed to have an adaptation to thriving in conditions where radiation is elevated because they first evolved when the levels were much higher than present,” says Nicol.
“Plants may be able to recall a dose of radiation received as seeds, much in the way that plants have a ‘memory’ of light. This can switch on genes or other mechanisms of adaptation including epigenetic changes that allow the plant to grow despite the stress.”
Nicol plans to study overall growth and measure antioxidant production to examine whether or not the plants have responded to the additional stress of soil contaminated with radionuclides.
