By Karya Naz Balkiz
Groundbreaking experiments conducted by Turkish scientists on Earth and in space could hold the key to humankind’s hopes of colonising other celestial bodies— the proverbial conquest of the last frontier in the near future.
And at the heart of one experiment is Schrenkiella parvula, a plant species that grows in Türkiye’s Salt Lake area.
“Human life is fundamentally dependent on plant life, on oxygen. If we want to establish colonies in space, we have to bring some plants along to support our existence,” says Associate Professor Rengin Ozgur Uzilday, who is leading Türkiye’s EXTREMOPHYTE experiment.
“For this, we need plants that can survive in extraterrestrial conditions,” she tells TRT World
Under the Artemis mission, NASA plans to build a long-term human community on the Moon. From there, they hope to “pave the way to Mars and beyond”.
However, the soil on these celestial bodies, called “regolith”, is completely different from the soil on Earth – it doesn’t harbour life, and its components are completely different, making it virtually inhabitable, Ozgur Uzilday explains.
The outermost layer of Mars, for instance, is toxic. According to data retrieved from rovers and orbiters, it’s marked by extreme levels of salt, aluminium, silicon, and magnesium and contains other chemical elements, including chromium and boron.
This is where Turkish scientists stepped in.
“We suggested that some plants from certain areas on Earth, where we observe extreme conditions, can also grow on these regoliths and successfully germinate and make photosynthesis,” Ozgur Uzilday says.
One of those “extremophyte” plants is Schrenkiella parvula, which has evolved to thrive in the extreme conditions of its local habitat in and around Salt Lake in central Anatolia.
It can absorb and store salt within its cells and thrives even in seawater, withstanding up to 600 millimolar salinity, the scientific measure of chemical concentration in liquids.
The salt-tolerant plant — scientifically grouped as a “halophyte” — can also endure lithium, chromium, boron and magnesium, which makes it capable of growing in soils that are toxic to most plants, emerging as a prime candidate for space agriculture.
But it’s not just the components of the regoliths that matter. One variable that cannot be tested on Earth is whether these plants could grow without gravity.
“So, the first thing we had to do was to observe whether this plant could survive in microgravity,” Ozgur Uzilday says.
Part of the experiment was conducted aboard the International Space Station by Türkiye’s first astronaut Alper Gezeravci, who spent 18 days in space in February this year.
Space vs Earth
Ozgur Uzilday’s team sent over 50 seeds to the orbiting lab where the Schrenkiella parvula was germinated and grown under salt stress, replicating conditions expected on the Moon or Mars.
“Our experiment on the ISS showed that the plant can survive and grow under salt stress in a microgravity environment, and even germinate directly from the seed under salinity,” she says.
There was an eight-day growth period during which the samples grew their first leaves and formed roots, exceeding expectations on how well the plant would perform, she adds.
Approaching his return, Gezeravci harvested the Schrenkiella parvula samples and preserved them in a fixative solution that froze the plant's tissue and genome at minus 80 degrees Celsius for the journey back. The samples made it to Ege University on February 29.
Ozgur Uzilday's team also replicated the ISS experiment on Earth so that they could examine how the space environment would affect the plants differently. They are now analysing the samples from the ISS in comparison to those grown on Earth.
“People are enthusiastically waiting for us to reveal that we examined differences. But what we really want to observe is that there won’t be any changes. These plants already flourish here on Earth, so we want to see the same results in our samples from the ISS,” Ozgur Uzilday says.
Compared to the samples from Earth, they so far haven’t seen major changes. One notable difference was that under microgravity, the plants had grown their roots in a rather peculiar manner.
“In terrestrial conditions, when a seed germinates, it moves its roots in the direction of gravity and its stems towards a light source. But this drastically changes in microgravity because the sense of direction by gravity is lost,” Ozgur Uzilday explains.
In the coming days, her team will use next-generation sequencing to examine the entire DNA and RNA sequence of the samples from both environments for potential differences.
Pioneer species
If it can maintain its tolerances in extraterrestrial conditions, the Schrenkiella parvula would not just survive on regoliths but also alter their composition and density, creating a more favourable environment for new life to flourish.
“The upper levels of regoliths are too dense. The plants that we consume cannot grow their roots in it. Moreover, regoliths cannot hold water the way soil does,” Ozgur Uzilday says.
That constitutes a major obstacle for space agriculture, especially considering water scarcity on other celestial bodies. “We would either have to transport large amounts of water from Earth or produce it in space, both of which would be quite costly,” she explains.
“Or we could explore ways to alter the regoliths themselves.”
The roots of pioneering plant species are considered capable of physically breaking down regolith and pulverising it, making it easier for other plants to take root while also increasing the regolith’s capacity to hold water, thus diminishing the amount needed for agricultural purposes.
What remains after that is the chemical composition of regoliths. Not only can regoliths be toxic, it is also virtually impossible for the plants we consume to survive in these environments due to the absence of organic matter.
“We propose that Schrenkiella parvula could be utilised as a cover crop on regoliths to prepare them for our agricultural needs,” Ozgur Uzilday tells TRT World.
Referring to the plant’s ability to absorb unwanted substances such as salt, chromium and aluminium, she adds that the plants could then “be harvested and burned, eliminating these substances from the regolith. They can then be replanted and composted to further prepare the soil for the plants we can consume.”
Ultimately, Schrenkiella parvula's ability to thrive in extreme environments offers a glimmer of hope for the prospect of agriculture in space, and a testament to the resilience of life.
Major step forward
“I got space biology lectures in the mid-2000s, now I teach it to my own students. Experiments in microgravity were a realm we could only observe from afar,” reflects Ozgur Uzilday.
When the Turkish Space Agency announced that it was accepting research proposals for the country’s first crewed space mission, they immediately applied.
“We study life, biology, but all life on Earth depends on gravity. It’s crucial for us to study whether our findings have any meaning in the microgravity environments, to see how much the living organisms change in those conditions,” she stresses.
In coordination with the Scientific and Technological Research Council of Türkiye (TUBITAK), they have been documenting and archiving all of their work to create a backlog for Türkiye’s future in space.
“We (as Turkish scientists) have now taken a major step forward with the opportunity to conduct our own experiments in space. … It’s thrilling that Turkish scientists can now contribute to the literature as well.”
