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Ülo Niinemets

How plant "talk" contributes to global change

 

Keynote for the IUFRO Landscape Ecology Conference “Sustaining ecosystem services in forest landscapes”, 23-30 August 2015, Tartu, Estonia

 

Plants face a multitude of abiotic and biotic stresses with varying severity throughout their life. Climate change involves modification of several environmental drivers, and is predicted to increase the frequency and severity of various abiotic and biotic stresses, including rising temperatures, increasingly uneven distribution of precipitation, and more frequent outbreaks of herbivore and pathogen attacks. As any stress reduces plant CO2 fixation, enhanced stress frequency and severity are expected to lead to faster rise of atmospheric CO2 concentration, thereby further exacerbating climate change. On the other hand, plants can importantly modify their own life environment by release of volatile organic compounds (BVOC) that participate in ozone- and aerosol forming reactions in ambient atmosphere and in cloud formation. Apart from constitutive emissions that are present in only some species and are expected to decrease under stress, especially under severe stress, all plants respond to stresses by induced BVOC emissions that serve as signal molecules eliciting stress response pathways and leading to plant acclimation. These induced BVOC emissions, the plant “talk”, also contribute to atmospheric processes and can potentially reduce the stress severity, and accordingly, stress-driven reductions in CO2 uptake. Thus, the stress responses and acclimation of vegetation to future environmental stresses can importantly modify the speed and magnitude of climate change.

 

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia