Scientist starts plant-only oxygen test at Eden Project
A scientist is spending 48 hours sealed inside an airtight chamber breathing in oxygen produced solely by plants.
Iain Stewart, a geoscience professor at the Plymouth University, started his experiment at the Eden Project in Cornwall on Thursday.
The challenge is also being filmed for a new BBC Two series, How Plants Made The World.
The aim is to demonstrate the importance of plants to human survival as the "lungs of the planet".
Before he started the challenge Prof Stewart said: "This experiment has never been done before with a human - it seems a fascinating challenge to see if plants really could keep a person alive.
"I cannot think of a more powerful way of driving home to the viewer the importance of photosynthesis."
Plants take in carbon dioxide and release oxygen using light as energy during photosynthesis.
Professor Stewart is carrying out his experiment in a 12 sq m (130 sq ft) see-through plastic container in Eden's Rainforest Biome.
He has a hammock to sleep in, a laptop to work on and an exercise bike to keep him moving.
The temperature and humidity are being kept at an optimum level for the plants, rather than for his comfort.
Special lights have also been placed both inside and outside the chamber to ensure the plants are continuously lit throughout the day and night, providing the energy for photosynthesis to take place.
Alistair Griffiths, curator of horticulture at Eden, said between 150 and 200 plants had been grown over the past three months for the experiment.
The plants include miscanthus, banana plants, maize and a mix of tropical herbs.