New Insights into Leaf Physiological Responses to Ozone for Use in Crop Modelling

TY - JOUR

T1 - New Insights into Leaf Physiological Responses to Ozone for Use in Crop Modelling

AU - Osborne, Stephanie Alice

AU - Pandey, Divya

AU - Mills, Gina

AU - Hayes, Felicity

AU - Harmens, Harry

AU - Gillies, David

AU - Bueker, Patrick

AU - Emberson, Lisa Dianne

N1 - © 2019 by the authors.

PY - 2019/4/1

Y1 - 2019/4/1

N2 - Estimating food production under future air pollution and climate conditions in scenario analysis depends on accurately modelling ozone (O₃) effects on yield. This study tests several assumptions that form part of published approaches for modelling O₃ effects on photosynthesis and leaf duration against experimental data. In 2015 and 2016, two wheat cultivars were exposed in eight hemispherical glasshouses to O₃ ranging from 22 to 57 ppb (24 h mean), with profiles ranging from raised background to high peak treatments. The stomatal O₃ flux (Phytotoxic Ozone Dose, POD) to leaves was simulated using a multiplicative stomatal conductance model. Leaf senescence occurred earlier as average POD increased according to a linear relationship, and the two cultivars showed very different senescence responses. Negative effects of O₃ on photosynthesis were only observed alongside O₃-induced leaf senescence, suggesting that O₃ does not impair photosynthesis in un-senesced flag leaves at the realistic O₃ concentrations applied here. Accelerated senescence is therefore likely to be the dominant O₃ effect influencing yield in most agricultural environments. POD was better than 24 h mean concentration and AOT40 (accumulated O₃ exceeding 40 ppb, daylight hours) at predicting physiological response to O₃, and flux also accounted for the difference in exposure resulting from peak and high background treatments.

AB - Estimating food production under future air pollution and climate conditions in scenario analysis depends on accurately modelling ozone (O₃) effects on yield. This study tests several assumptions that form part of published approaches for modelling O₃ effects on photosynthesis and leaf duration against experimental data. In 2015 and 2016, two wheat cultivars were exposed in eight hemispherical glasshouses to O₃ ranging from 22 to 57 ppb (24 h mean), with profiles ranging from raised background to high peak treatments. The stomatal O₃ flux (Phytotoxic Ozone Dose, POD) to leaves was simulated using a multiplicative stomatal conductance model. Leaf senescence occurred earlier as average POD increased according to a linear relationship, and the two cultivars showed very different senescence responses. Negative effects of O₃ on photosynthesis were only observed alongside O₃-induced leaf senescence, suggesting that O₃ does not impair photosynthesis in un-senesced flag leaves at the realistic O₃ concentrations applied here. Accelerated senescence is therefore likely to be the dominant O₃ effect influencing yield in most agricultural environments. POD was better than 24 h mean concentration and AOT40 (accumulated O₃ exceeding 40 ppb, daylight hours) at predicting physiological response to O₃, and flux also accounted for the difference in exposure resulting from peak and high background treatments.

KW - ozone; air pollution; wheat; photosynthesis; leaf senescence; crop modelling

KW - Crop modeling

KW - Air pollution

KW - Ozone

KW - Leaf senescence

KW - Photosynthesis

KW - Wheat

UR - http://www.scopus.com/inward/record.url?scp=85067993006&partnerID=8YFLogxK

U2 - 10.3390/plants8040084

DO - 10.3390/plants8040084

M3 - Article

C2 - 30939811

SN - 2223-7747

VL - 8

JO - Plants

JF - Plants

IS - 4

M1 - 84

ER -