Plant Secondary Compounds in Soil and Their Role in Belowground Species Interactions.

According to a new study published in the journal Trends in Ecology and Evolution, changes in the production of PSCs can lead to unforeseen consequences for soil structure and function and can disturb biological feedbacks on soil chemistry and biology, perhaps even on atmospheric chemistry and climate. Figure: © Trends in Ecology and Evolution, 2020.

Secondary compounds (PSCs ) in plants (formed from primary metabolites in specific pathways) are major contributors to the chemical diversity of nature.. The distribution of PSCs is heterogeneous across the plant kingdom, and these compounds exhibit extensive variation both among and within species. Knowledge of the effect of PSCs on belowground interactions in the more diffuse community of species living outside the rhizosphere is sparse compared with what we know about how PSCs affect aboveground interactions.

In a new study published in the journal Trends in Ecology and Evolution authors illustrate that PSCs from foliar tissue, root exudates, and leaf litter effectively influence such belowground plant–plant, plant–microorganism, and plant–soil invertebrate interactions.

The study shows that soil is a theater of facilitation, symbiosis, and warfare deployed by plants and the various organisms living in it, and PSCs have a major role mediating many of these interactions. Plants and soil organisms have adapted to withstand, detoxify, or use the cocktail of PSCs originally meant to harm some of them. ”Therefore, understanding PSC-mediated relationships at the community scale and identifying the compounds involved in these interactions is important for better insight into the functioning of these systems and their evolution, especially in changing environments” said Dr. Bodil K. Ehlers from Aarhus University, Denmark

According to the study climatic factors can induce PSC production and select for different plant chemical types. “Therefore, climate change can alter both quantitative and qualitative PSC production, and how these compounds move in the soil. This can change the soil chemical environment, with cascading effects on both the ecology and evolution of belowground species interactions and, ultimately, soil functioning” said Prof. Josep Penuelas from CREAF-CSIC Barcelona.

“We encourage the creation of open, community-wide, curated, labeled, broad-spectrum PSC data sets across plant species and soils, because this would greatly increase the transfer of knowledge between scientists studying plants, microbes, and invertebrates in this biological belowground theatre” added Prof. Josep Penuelas from CREAF-CSIC Barcelona.

.Reference: Ehlers, B.K., Berg, M.P., Staudt, M., Holmstrup, M., Glasius, M., Ellers, J., Tomiolo, S., Madsen, R.B., Slotsbo, S., Penuelas, J. 2020. Plant Secondary Compounds in Soil and Their Role in Belowground Species Interactions. Trends in Ecology & Evolution, doi: 10.1016/j.tree.2020.04.001.

Towards a new generation of vegetation models

Plants and vegetation play a critical role in supporting life on Earth, but there is still a lot of uncertainty in our understanding of how exactly they affect the global carbon cycle and ecosystem services. A new IIASA-led study explored the most important organizing principles that control vegetation behavior and how they can be used to improve vegetation models.

We rely on the plants that make up our planet’s ecosystems to release oxygen into the atmosphere, absorb carbon dioxide (CO2), and provide habitat and food for wildlife and humans. These services are critical in the future management of climate change, especially in terms of CO2 uptake and release, but due to the many complex, interacting processes that affect the ability of vegetation to provide these services, they remain difficult to predict.

In an IIASA-led perspective published in the journal Nature Plants, an international team of researchers endeavored to address this problem by exploring approaches to master this complexity and improve our ability to predict vegetation dynamics. They explored key organizing principles that govern these processes – specifically, natural selection; self-organization (controlling collective behavior among individuals); and entropy maximization (controlling the outcome of a large number of random processes). In general, an organizing principle determines or constrains how components of a system, such as different plants in an ecosystem or different organs of a plant, behave together. Mathematically, such a principle can be seen as an additional equation added to a system of equations, allowing one or more previously unknown variables in the system to be determined and thereby reducing the uncertainty of the solution.  

A lot of research has gone into understanding and predicting how plant processes combine to determine the dynamics of vegetation on larger scales. To integrate process understanding from different disciplines, dynamic vegetation models (DVMs) have been developed that combine elements from plant biogeography, biogeochemistry, plant physiology, and forest ecology. DVMs have been widely used in many fields including the assessment of impacts of environmental change on plants and ecosystems; land management; and feedbacks from vegetation changes to regional and global climates. However, previous attempts to improve vegetation models have mainly focused on improving realism by including more processes and more data. This has not led to the expected success because each additional process comes with uncertain parameters, which has in turn caused an accumulation of uncertainty and therefore unreliable model predictions.

“Despite the ever-increasing availability of data, and the fact that vegetation science, like many other scientific fields, is benefitting from increasing access to big data sets and new observation technologies, we also need to understand governing principles like evolution to make sense of the big data. Current models are not able to reliably predict long-term vegetation responses,” explains lead author Oskar Franklin, a researcher in the IIASA Ecosystems Services and Management Program.  

“The study found that by representing the principles of evolution, self-organization, and entropy maximization in models, they could better predict complex plant behavior and resulting vegetation as an emerging result of environmental conditions” explains one of the members of the international team of researchers, Josep Penuelas from CREAF-CSIC Barcelona. [JP1] Although each of these principles had previously been used to explain a particular aspect of vegetation dynamics, their combined implications were not fully understood. This approach means that a lot of complex variation and behavior at different scales, from leaves to landscapes, can now be better predicted without additional understanding of underlying details or more measurements.

The authors expect that apart from leading to better tools for understanding and managing the biosphere, the proposed “next-generation approach” may result in different trajectories of projected climate change that both policy and the general public would have to cope with.


Franklin O, Harrison S, Dewar R, Farrior C, Brännström A, Dieckmann U, Pietsch S, Falster D, ….Penuelas J,….et al. (2020). Organizing principles for vegetation dynamics. Nature Plants DOI: 10.1038/s41477-020-0655-x


Researcher contact

Oskar Franklin

Research scholar

Ecosystems Services and Management Program

Tel: +43 2236 807 251

Resource: Press Officer

Ansa Heyl

IIASA Press Office

Tel: +43 2236 807 574

Mob: +43 676 83 807 574

About IIASA:

 [JP1]Això ho he tocat jo per adaptar-ho al nostre ambit d’actuació…jo no hi era a la nota original, com es lògic.