AnaEE Science Conference 2026

Combining Ozone Uptake and Leaf Structure to Improve Predictions of Ornamental Plant Responses to Tropospheric Ozone

Not scheduled

15m

Palais de l'Europe

Poster Session 4: Experimental Approaches to Global Change Ecology Session 4: Experimental Approaches to Global Change Ecology

Speaker

Jacopo Manzini (IRET-CNR)

Description

Tropospheric ozone (O₃) is one of the most important air pollutants affecting urban and peri-urban vegetation, particularly in the Mediterranean region, where climatic conditions favor its formation and accumulation. Traditional ozone risk assessment methods, such as the concentration-based AOT40 index, do not account for the actual uptake of ozone by plants. Flux-based approaches, including the Phytotoxic Ozone Dose (POD1), provide a more biologically relevant estimate by quantifying stomatal ozone uptake. However, these methods do not consider leaf structural traits that strongly influence plant tolerance to ozone stress.
This study evaluated the effectiveness of a novel metric, the Leaf Index Flux (LIF), which combines POD1 with Leaf Mass per Area (LMA), a key functional trait associated with leaf robustness and resistance to oxidative damage. Fifteen ornamental tree species, including both evergreen and deciduous taxa commonly used in urban landscapes, were exposed to ambient and elevated ozone concentrations in a Free-Air Controlled Exposure (O₃-FACE) facility at the National Research Council (CNR) experimental site in Sesto Fiorentino, Italy. Ecophysiological responses, including net photosynthesis, stomatal conductance, dark respiration, chlorophyll fluorescence, and relative chlorophyll content, were measured and related to three ozone metrics: AOT40, POD1, and LIF.
Marked interspecific differences in LMA were observed, with Mediterranean evergreen species generally exhibiting higher values than deciduous species, reflecting greater structural investment and potential ozone tolerance. Among the evaluated metrics, LIF consistently showed the strongest relationships with physiological responses. It provided the best prediction of photosynthetic decline, increased respiratory costs, and reductions in photosystem II efficiency under ozone stress.
These findings demonstrate that plant responses to ozone are determined not only by the amount of pollutant absorbed but also by leaf structural characteristics. By integrating physiological and morphological components, LIF offers a more comprehensive and biologically meaningful assessment of ozone stress and species tolerance. The adoption of this metric could improve ozone risk assessment, support the selection of more resilient ornamental species, and enhance urban green infrastructure management under future scenarios of increasing air pollution and climate change.