Photosynthesis misunderstood

ANU researchers have overturned 20 years of thinking about the powerplant which enables photosynthesis to occur, sending biologists, chemists and physicists back to the drawing board.

The chemical reaction which provides energy for photosynthesis, enabling plants to convert sunlight into energy and oxygen, is the most powerful process in biology - but ANU research indicates that it has been misunderstood for two decades. The finding could take scientists a step closer to identifying a new sustainable energy source.

Professor Elmars Krausz, PhD student Joe Hughes and a team of researchers at ANU have found that the wavelength of light needed for oxygen production is much longer than previously thought.

Using high-resolution lasers, they have also found that the rate at which energy is fed into photosynthetic reaction centres is very strongly controlled by biological 'speed humps' - again a great surprise and opposite to what had been thought.

The Dean of the Research School of Chemistry, Professor Denis Evans, said the finding was a major breakthrough in our understanding of the chemistry that supports life.

"This is one of the significant breakthroughs which change the course of research in the field," Professor Evans said. "It clearly underscores the incredible importance of fundamental research and the need to provide adequate funding for basic and enabling research in Australia."

Professor Krausz added: "For decades people have tried to explain this oxygenic photosynthesis by relating it to a process that occurs in bacteria, which is far older in evolutionary terms.

"It was like trying to fit a square peg into a round hole. We took a close look at the peg then used advanced techniques developed in physics and chemistry together with the best biological samples available. We found we needed a round peg. There is now an exciting new way of approaching this violent beast.

"Thousands of researchers worldwide have been trying, for decades, to understand this process. This breakthrough has only become possible through the efforts and cooperation of a cross-disciplinary team at ANU working on photosynthesis, spectroscopy and biochemistry."