Evaluating how plant stress impacts our climate

The work of ERC grantee Ülo Niinemets has shown that monitoring plant stress emissions could help us to better understand atmospheric processes. This has led to a rethink on global climate modelling and strengthened research into crop resilience. His project’s successful international collaboration has also demonstrated how ERC funding can boost scientific excellence in smaller countries like Estonia.  

Many plants release carbon into the atmosphere at night. What is less well-known, however, is that these emissions also contain a variety of volatile components. Ülo Niinemets, from the Estonian University of Life Sciences, wanted to demonstrate that not only are these emissions a reaction to stress, but also that they should be taken into account in climate modelling.

"When we think about the life of plants, we tend to focus on their ability to convert solar energy in order to grow and develop", he notes. ‘We forget that plants also experience stress in terms of temperature, nutrient scarcity and predators."

The volatile compounds emitted as a result of this stress can have a positive impact on the climate due to their contribution to the formation of clouds and aerosols, both of which can have a cooling effect. Aerosols, in particular, help to reduce the level of solar radiation present in the atmosphere, which in turn helps to lower temperatures.

Considering that most climate models have severely underestimated the impact of these factors, Niinemets aimed to attain a better and more accurate understanding of the role of plants in Earth processes and climate change.

The ERC grant was critical in enabling Niinemets to carry out this pioneering work. "If you come from a small country like Estonia with limited resources, this kind of research can be a very difficult thing to do", he says.

Re-thinking climate modelling

With the help of ERC funding, Niinemets was able to investigate a range of plant stress emissions, from what happens at the level of a single leaf to an entire canopy. His project focused on both the regional and the global impact of these emissions.

"When we started, very few people were thinking in this direction", he says. "This meant that most atmospheric or climate models did not include plant stress emissions. The role of plant emissions, which can condense to form aerosols, was often the weak part of climate reports."

By providing concrete data on plant stress emissions at a global level, Niinemets hopes to address this weakness, ensuring that such emissions are fully taken into account in the future and that climate reports are more robust and accurate.

A critical thread running throughout the project has been international collaboration. Chinese and Korean scientists were able to visit Niinemets’ lab to start work on a line of experiments designed to strengthen plant stress tolerance using bacteria.

"This research focused on important crops like rice, and forest trees like eucalyptus", says Niinemets. "We found that certain bacteria allow plants to extract nutrients from relatively infertile soil, and to improve their resistance to drought."

From stress to resilience

On a practical level, this collaborative research could lead to applications in the field of agriculture. New tools designed to detect stressful conditions early could enable farmers to identify when a plant or crop is stressed, and take appropriate action.

As Niinemets points out, once a crop is being eaten by a pest, it is often too late to save. "Sensitive monitoring of volatile compound initiatives could help farmers to diagnose exactly what the problem is", he says. "We plan to continue this research, to try to understand the evolution of volatile emissions right down to the molecular level."

Niinemets is one of only about a dozen Estonian researchers to be awarded an ERC grant. He believes that the project’s ambitious objectives, groundbreaking findings and international focus have provided an important boost for the country’s research community.

"Working with other countries has been hugely beneficial", he says. "I now have 11 nationalities in my lab. This exposes young Estonian researchers to a wider world, encourages them to speak in English and to work in an international setting."

How the ERC transformed science: interview with Ülo Niinemets


About the researcher

Professor Ülo Niinemets is an environmental scientist and biologist, specialising in the physiology of volatile organic compound emissions. He is Professor of Crop Science and Plant Biology within the Institute of Agricultural and Environmental Sciences at the Estonian University of Life Sciences, based in Tartu, Estonia. Niinemets won an ERC Advanced Grant in 2012.