GARDENING IN SPACE
Dr Greg Briarty, gave us a fascinating look into the future with his talk on space travel. Having spent most of his academic career teaching Botany at Nottingham University – and also helping NASA design space rockets in recent times. He outlined the difficulty of sustaining life in this new climate inside the space capsule itself. Microgravity is a major problem in Space as our plants on Earth rely on 1G for their physiology to work effectively. For example, when apples fall, they accelerate at 1G.
In order to survive in Space, humans have to rely on recycling. Apart from sunlight all their resources are contained within the space capsule – therefore they have to be reused. Also, plants have to perform in a new environment in order to provide food, release oxygen, and absorb carbon dioxide. Their minerals also have to be made available to the next generation by composting.
Dr Briarty outlined several experiments designed to find out varieties that would be most tolerant to these new conditions. Some of these involved children growing batches of seed on Earth and comparing them with the same batches used by astronauts in the International Space Station. Tim Peake was involved in some of these projects in 2004 and they grew ’Arab / Wild cress’ as it is quick to germinate. After 5 months they found that the Earth seeds grew faster than the Space batches. This was partly due to the hormone auxin not falling to the lower portion of the root in space, as it does on Earth. Microgravity was the reason for this. Analysis also showed that in space the conversion of starch to oil was slowed down , and this would also have reduced growth. In addition, it was found that the next generation of space seeds had developed 80% less cells than those on Earth.
There were many other problems for plants to overcome in the capsule environment. For example, gas exchange is impaired in Space as hot air does not rise in this environment. Therefore, the movements of oxygen and carbon dioxide were badly affected, and this would seriously impair the physiology of the plants. Also, water collected around the plants that had been watered and was not absorbed as on Earth. As for the genes some varieties showed that they had slowed down in growth and other varieties had grown faster. However, they have managed to grow lettuce, Japanese Cabbage (Mizuna) and cress in the space capsule.
Therefore the astronauts have found that survival in space requires many aspects of science to be controlled precisely, such as: sunlight, cosmic rays, temperature, vibration, the energy requirement, mass and weight of capsule. Dr Briarty explained how difficult it was to do this and the progress that had been made so far. However, the audience were advised not to book their tickets to Mars just yet!