Deciphering the ozone-induced changes in cellular processes: a prerequisite for ozone risk assessment at the tree and forest levels

Abstract

Abstract& Key message Ozone, one of the major atmospheric pollutants, alters tree growth, mainly by decreasing carbon assimilation and allocation to stems and roots. To date, the mechanisms of O 3 impact at the cellular level have been investigated mainly on young trees grown in controlled or semi-controlled conditions. In the context of climate change, it is necessary to introduce a valuable defence parameter in the models that currently predict O 3 impact on mature trees and the carbon sequestration capacity of forest ecosystems.

Ozone effects on European forest growth—Towards an integrative approach

“…() simulated a significant decrease in growth at the Kranzberg beech site at long time‐scales, especially at younger or less dense stands (reduction from 5% to 15% after 5 years). However, there are still a lot of uncertainties regarding the implementation of ozone response functions for most of the physiological processes due to the complexity of the mechanisms that are involved in ozone impacts (Jolivet et al., ), and due to the general lack of high‐resolution data at both temporal and spatial scales on this topic, which reduces the possibility of model calibration for multiple species, especially for adult trees. Indeed, most of the PBMs use DRRs that derived from seedlings growing under controlled experiments (see Table ).…”

“…Tropospheric ozone is considered to be currently more damaging to vegetation than any other air pollutant, impacting air quality and various ecosystem functions and services (Ainsworth, Yendrek, Sitch, Collins, & Emberson, ; Fuhrer et al., ; Matyssek, Karnosky, et al., ; Sitch, Cox, Collins, & Huntingford, ). As a strong oxidant, ozone has a negative impact on many cellular and molecular processes (see Jolivet et al., ). Among others, ozone induces an alteration of Rubisco activity and content through the formation of reactive oxygen species (Saxe, ), a reduction in stomatal conductance (Ainsworth et al., ), leaf chlorosis and early senescence (Novak et al., ; Sicard, De Marco, et al., ; Waldner et al., ; but see Ferretti et al., ).…”

“…De Vries, Du, et al., ; Pretzsch, Biber, Schütze, Uhl, & Rötzer, ). Also, depending on species‐specific stomatal regulation strategy, drought‐induced stomatal closure may reduce ozone uptake (Jolivet et al., ). In the long‐term, O 3 effects on forest growth may also be potentially reduced by acclimation/adaptation processes (Zak, Pregitzer, Kubiske, & Burton, ), and compensated by changes in competition intensity and species composition (Wang, Shugart, Shuman, & Lerdau, ).…”

“…On the basis of reviews and opinion papers on ozone impacts on tree physiology and forest ecosystems (e.g. Ainsworth et al., ; Andersen, ; Ashmore, ; De Vries, Dobbertin, et al., ; Ferretti et al., ; Fuhrer et al., ; Jolivet et al., ; Matyssek & Sandermann, ; Paoletti, ; Sicard, Augustaitis, et al., ; Simpson et al., ) and on upscaling considerations (e.g. Karnosky et al., ; Kolb & Matyssek, ; Matyssek et al., ; Samuelson & Kelly, ), we suggest research directions from a “forest growth” rather than from an “air pollution” perspective.…”

Effects of soil nutrient availability and ozone on container-grown Japanese larch seedlings and role of soil microbes

“…Other O 3 molecules enter the leaf through stomata during gas exchange processes (Paoletti and Grulke 2005). Elevated O 3 uptake by stomata can inhibit leaf area growth, decrease carbon uptake and Rubisco and chlorophyll content, alter growth, and suppress productivity of forest plants (Paoletti and Grulke 2005;Wittig et al 2009;Jolivet et al 2016;Li et al 2017a, b;Cailleret et al 2018). Because of the negative O 3 effects on forest plants and associated ecological processes (Karnosky et al 2005;Ainsworth et al 2012;Blande et al 2014;Agathokleous et al 2016b;Chappelka and Grulke 2016;Braun et al 2017), we must understand the biology of O 3 -induced stress and devise innovative methods to mitigate the deleterious effects of O 3 .…”