Australian Researchers Show How Plants Secretly Decide How Much CO2 They Store

By absorbing some of the carbon dioxide (CO2) we emit into the atmosphere, plants help us fight global warming. However, plants also emit some of this CO2, which limits their effectiveness as carbon sinks. It is therefore important to understand how plants decide how much CO2 they store.

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Plants use sunlight and water to convert carbon dioxide (CO2) in the atmosphere into oxygen (02) and energy. This is the well-known principle of photosynthesis, whereby plants absorb CO2 which helps counteract global warming. What is perhaps less well known is that plants also breathe. In doing so, they emit up to half of the CO2 they absorb back to the environment. This limits their ability to help us fight global warming.

Researchers at the University of Western Australia are now telling us how plants decide when and how much CO2 to put into the atmosphere. The secret seems to be hidden in mitochondria, organelles involved in many cellular processes.

The mechanism involved in this process has been unknown to scientists until now. But they have discovered a metabolic channel that is attached to mitochondria and that directs a product involved in the transformation of sugar- known to researchers as pyruvate – towards respiration which results in CO2 being released. Pyruvate produced by other means is stored by plant cells to produce biomass. However, when the metabolic channel is closed, this pyruvate is also used for respiration.

Thus, it appears that the plant is able to choose one source of pyruvate over another for CO2 release. “Understanding the secret of plant respiration that prioritizes carbon release over conservation for biomass production provides a new opportunity to influence the last-minute decision,” said Professor Harvey Millar in a University of Western Australia press release. “By limiting this channel to respiration or creating new channels to direct carbon from mitochondria to biomass production, we can limit CO2 release from plants. This shows that current discussions about net-zero emissions and the role that crops, forests, and grasslands can play need to include discussions about what happens in plants.”