Ülo Niinemets

Stress-Induced Plant Volatiles in Biosphere-Atmosphere System

This study delved into plant-generated volatile organic compounds (VOCs) and their impact on Earth’s atmosphere and environment, highlighting their overlooked role in large-scale Earth processes. It aimed to assess how induced VOC emissions under stress conditions contribute to air composition, focusing on their relationship with environmental stress severity across plant species. By developing and verifying a quantitative model for induced VOC emissions, the project sought to scale up its findings to regional and global levels, evaluating their significance in the overall VOC budget. Additionally, the study explored the complex feedback between stress, ozone, secondary organic aerosols, cloud condensation nuclei formation, and Earth climate, offering valuable insights into plant ecology and Earth system processes.

Result & Impact

The project made major contributions to understanding plant stress tolerance and the role of vegetation in atmospheric reactivity and climate. It provided fundamental insights into how plants with varying stress resilience respond to environmental limitations, extending the influential concept of “leaf economics spectrum” in plant ecology. It also delivered the first quantitative evidence of the large-scale importance of plant volatile organic compounds, showing that their emissions, especially stress-induced ones, have been underestimated. These findings reveal that plants influence the climate more strongly than previously thought, and the data can now be incorporated into regional and global climate models to improve predictions of climate change. Beyond science, the results open opportunities for agriculture: sensitive monitoring of volatile emissions could allow farmers to detect crop stress early, diagnose problems with unprecedented accuracy, and take timely action.

Enhanced productivity of resurrection photosynthetic organisms in a CO₂-richer future: tipping the global carbon and oxidant balance

As global carbon dioxide levels continue to rise, plants play a critical role in absorbing human-generated carbon dioxide emissions and mitigating climate change. Their capacity, however, is reaching saturation. This project focuses on resurrection photosynthetic species such as mosses and lichens that are not yet at their photosynthetic CO₂ saturation point. These organisms thrive in extreme environments and have abilities to resume photosynthesis after desiccation, offering potential for enhancing carbon capture in the future.

Niinemets plans to investigate how these species respond to elevated carbon dioxide levels and how they influence both global carbon uptake and atmospheric oxidant levels. The research seeks to uncover whether mosses and lichen could tip the balance toward a more sustainable climate trajectory and become the balancing factor in the future global carbon cycle.

Result & Impact

The project is expected to provide groundbreaking insights into the physiology of resurrection photosynthetic organisms and their ability to sustain or even enhance productivity under rising atmospheric carbon dioxide. By characterising their unique mechanisms of carbon capture and stress resilience, the research will expand the current models of the global carbon cycle, which largely overlook these species. The findings will clarify whether mosses, lichens, and similar organisms can increase their contribution to carbon sequestration and help counterbalance the declining photosynthetic capacity of other plants. The study will also assess how these organisms influence atmospheric oxidant levels, with implications for air quality and climate feedbacks. The project may identify new strategies for climate mitigation inspired by natural resilience, as well as highlight the importance of conserving these often-overlooked organisms.