Plants from all over the globe respond to temperature changes in remarkably similar ways, researchers have found. The finding has important implications for climate modelling.

The research, published in the journal Proceedings of the National Academy of Sciences, is the most comprehensive study of plant respiration responses to temperature ever conducted.

Plants from habitats all over the world were examined by an international team of researchers. Despite the diversity in the plant types surveyed the results point to striking similarities in how different plants alter their respiration rate in response to increasing temperature.

Cellular respiration is the set of metabolic reactions used by plants to make usable energy for growth and cell maintenance. Plants release carbon dioxide during cellular respiration as a by-product of converting sugars into energy.

Researchers measured the respiration rates of vegetation at eighteen remote sites around the world which represented seven different types of plant habitat. They found that the sensitivity of respiration to temperature decreases as plants warm.  

“We looked at a wide range of plants growing in contrasting environments, from the arid woodlands of Western Australia, to the deciduous forests of New York, the arctic tundra in Alaska, the boreal forests of Sweden and the tropical forests of Costa Rica and Peru” said Professor Owen Atkin, from the ARC Centre of Excellence in Plant Energy Biology and the ANU Research School of Biology, who led the study.

“We found that there were predictable patterns of respiration across the globe.

“We saw that in the cold, respiration is more sensitive to temperature than previously thought and that the sensitivity of respiration declines at higher temperatures.  Amazingly, these patterns were remarkably uniform across all the habitats and plant types studied.”

The finding points to universally conserved controls of temperature responsiveness across the world’s plant life.

The patterns revealed by the study are important for climate modelling as they differ from a previous assumption that the temperature sensitivity of plant respiration is constant as leaves heat up.

“Currently, climate models assume that respiration doubles for each 10°C rise in temperature” said co-author Professor Mark Tjoelker of the Hawkesbury Institute for the Environment at Western Sydney University.

The reality that, across multiple plant species, respiration is more temperature sensitive that previously assumed and becomes less sensitive as the temperature rises is valuable information for creating accurate climate models.

Plant respiration is a major contributor of carbon to the atmosphere and plays a key role in the global carbon cycle. Climate models are routinely used to predict how warm the Earth will be later this century. Central to this is the prediction of carbon flows between plants and the atmosphere.

“The findings of this study have important consequences for estimating carbon storage in vegetation, and for predicting concentrations of atmospheric carbon dioxide and future surface temperatures" said lead author, Dr Mary Heskel, now based at the Marine Biological Laboratory in Woods Hole, USA.

“Using this information models can now far more accurately predict carbon-exchange in ecosystems.”

The work was performed by an international collaboration of researchers, including the ARC Centre of Excellence in Plant Energy Biology at ANU, Western Sydney University, and several leading institutions in the USA, UK, Sweden and New Zealand.