Lettuce samples from the International Space Station are being studied to determine the effects of microgravity on crop development.
ARC Centre of Excellence in Plants for Space researchers, Dr Troy Miller and Professor Harvey Millar, from The University of Western Australia's School of Molecular Sciences, are collaborating with NASA on their Plant Habitat-07 (PH-07) project.
The experiment aims to study romaine lettuce grown in spaceflight conditions, to identify its response to varying moisture levels combined with the unique water dynamics under microgravity.
"Water acts very differently without gravity, and it becomes a balancing act between flooding or underwatering plants in space," Professor Harvey said.
In collaboration with the team at the NASA Kennedy Space Centre including Dr Gioia Massa, the lettuce samples were grown on the International Space Station between December 2024 and March 2025, under several different watering regimes.
In October this year the team at UWA's International Space Centre received both leaf and root samples, to conduct detailed analysis of the space-grown crops.
Initial outcomes of the experiment show that plants have significant metabolic differences when grown in spaceflight compared to on Earth.
"We are now looking deeper to determine if this response is detrimental to plant productivity or a clever adaptation mechanism to growing in space," Dr Miller said.
The plant response to different moisture level treatments has also provided key information to effectively water plants in microgravity.
Results from the study will guide the development of new plant growing systems optimised for watering in the absence of gravity and give rise to more nutrient-dense crops for astronauts to eat.
"This experiment underpins how remarkably responsive plants are to their environment and provides us with unique ways to discover novel fundamental aspects of plant development and stress adaptation," Dr Miller said.
The analysis gives insights in to how plants respond metabolically when grown during spaceflight, to help feed astronauts on future space exploration missions.
It also provides a unique perspective to find novel approaches in developing flood and drought-tolerant crops grown here on Earth.
