Nanoparticles do enter through leaves into tree stems: What now? Paolo Cherubini.

Abstract

Air pollution is of major concern to societies for its effects on the environment and on human health. In rapidly industrializing regions of the world, particulate pollution is a serious problem. Monitoring atmospheric pollution in industrial areas is essential to infer past levels of contamination and to evaluate impacts on environmental health. However, the first stations measuring air pollutants were only installed during the 1980s, and data currently available in most regions cover at best the past 40 years. We hypothesized that tree-ring chemistry can be used for monitoring spatio-temporal variability of air pollutants, extending air quality records back in time.

Recently, it has been discovered that not only gases but also small solid particles, i.e., nanoparticles, can enter through stomata into tree leaves and be transported into the stem wood, probably via the phloem. We still don't know exactly the trafficking of particles in trees, their transport mechanisms, whether and how they pass through the cell membrane and if they are in the symplast or apoplast of the wood. However, this is an important discovery that opens up new avenues of research. Can we use trees to trap and store dust from air pollution? Can we use tree rings as a record of past dust concentrations in the air - for example from volcanic eruptions? And, of utmost importance, what effects do nanoparticles have on tree physiological processes?

Here, I will present the story behind this discovery, and highlight the unanswered questions and the needs of research.

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Short bio

Paolo Cherubini's research interests lie within tree physiology, forest ecology, and evolution, with relevance to the knowledge and sustainable management of natural resources, and nature conservation. He strives to understand the key processes behind tree growth, to gain a thorough understanding of the influence of environmental stress on tree physiological processes, with particular focus on the impact of environmental stress on wood formation. Linking dendrochronology, dendroecology with ecophysiology is the main aim of his research.

Dr. Cherubini is Senior Scientist in the Dendrosciences group at the WSL Swiss Federal Institute for Forest, Snow and Landscape Research (Birmensdorf, Switzerland), a research institute of the ETH Domain. He is Adjunct Professor in the Department of Forest and Nature Conservation at the Faculty of Forestry of the University of British Columbia, Vancouver BC (Canada), Lecturer at the Department of Geography of the University of Zurich (Switzerland), Adjunct Senior Research Scientist at the Lamont-Doherty Earth Observatory of the Columbia University in New York City (U.S.A.), Adjunct Faculty at the University of Nebraska-Lincoln (U.S.A.), Guest Professor at the Institute of Earth Environment of the Chinese Academy of Sciences (CAS) in Xian, China. He is editorially very active: he served for 20 years (2003-2022) as Editor in Chief - and is currently Honorary Editor - of the journal Dendrochronologia,  2002-2011 as Associate Editor of Tree-Ring Research, 2011-2021 as Associate Editor of the Canadian Journal of Forest Research, 2007-2018 as member of the Editorial Board of Geochronometria, and has been member of the editorial board of iForest, Journal of Vegetation Science, and Tree Physiology.