Scientists from Mahidol University in Thailand have been exploring the potential of watermeal, the smallest flowering plant on Earth, as a source of nutrition and oxygen for astronauts. The research at the European Space Agency’s (ESA) ESTEC technical center in the Netherlands involved subjecting the tiny aquatic plants to hypergravity conditions aboard ESA’s Large Diameter Centrifuge (LDC).
These hypergravity conditions mimicked the International Space Station (ISS) but could be maintained for extended periods – up to a year. The tests were designed to see how simulated weightlessness affected the plant’s cell structure and growth rates and whether or not this decoupled from its ability to retain oxygen.
The results, published in the journal Scientific Reports, showed that despite exposure to hypergravity for only short periods, the plants exhibited apparent long-term effects on their growth and cell structure. These were most pronounced in the roots, with the marrow of the plants growing much more significantly than usual. This change was due to an increase in the concentration of calcium and magnesium, both essential elements for the growth of plants. The study also found that the root tips of the plants became more densely branched, resulting in the roots becoming taller.
Other cellular responses included increased protein production and cell wall formation. The research team also compared the effect of vibration on hypergravity-induced alterations to those caused by static gravity loads alone. While both g load and vibration induced a similar pattern of cellular alterations, the effects were less pronounced when the g load was combined with vibration.
The work was done at ESA’s ESTEC technical center in Noordwijk, the Netherlands. ESTEC is the technical heart of Europe’s space effort, where most ESA projects are initiated and developed and where all aspects of a mission are tested – from science and exploration missions to satellite navigation and human spaceflight. ESTEC is Europe’s largest space establishment and includes the European Space Research and Technology Centre, environmental test facilities for spacecraft systems, and support engineering laboratories.