Poplars are widely used for pulp and wood production and as model tree in research on air pollution effects on plant physiology. They are generally known to be ozone-sensitive. However, our knowledge of flux-based ozone dose-response (DR) relationships is still limited. According to the meta-analytic review by Prof. Z. Feng (NUIST, China), hybrid poplars may be more sensitive to ozone than non-hybrid ones. An important question has therefore raised if there are different sensitivities to ozone between native poplars and clones. The main objective of this study was to carry out a synthesis of experimental results about the ozone effects on poplars to develop ozone DR relationships for biomass growth reductions using exposure-based (AOT40, Accumulated Ozone exposure over a Threshold of 40 ppb) and flux-based (POD1, Phytotoxic Ozone Dose per leaf area above a threshold of 1 nmol m-2 s-1) indices. According to the result, we calculated a critical level (CL) for a 4% biomass reduction. We summarised literature data (Chinese Open-Top Chamber [OTC] experiments on five hybrid clones) and our own data in previous experimental studies at a Free-Air Controlled Exposure (FACE) and OTCs on hybrid clones (Oxford and I-214) and one non-hybrid European native species (P. nigra). The flux-based POD1 showed a slightly higher R2 value of DR relationships than AOT40 for both hybrid and non-hybrid native poplars. The flux-based CL was 6.6 mmol m-2 POD1 for hybrid poplars while the CL for the non-hybrid native species was 9.5 mmol m-2 POD1, suggesting that non-hybrid native species may be relatively less sensitive to ozone. Those CLs were higher than those previously investigated for the other ozone sensitive species such as beech (Fagus sylvatica L.) and birch (Betula pendula Roth.)(5.2 mmol m-2 POD1). Considering the very high stomatal conductance of poplar species (gmax = 348-575 mmol O3 m-2 PLA s-1), the potential risk of negative impacts for this species should be high.
For setting flux-based critical levels for ozone effects on poplars / Hoshika Y., Pollastrini M., Marzuoli R., Gerosa G., Calatayud V., Feng Z., Agathokleous E., Sicard P. Moura B., Paoletti E.. - ELETTRONICO. - (2024), pp. 1-1. (Intervento presentato al convegno 31st biennal conference on the IUFRO Research Group 8.04 on Air Pollution and climate change tenutosi a Bangkok nel 15-19 January).
For setting flux-based critical levels for ozone effects on poplars.
Pollastrini M.;
2024
Abstract
Poplars are widely used for pulp and wood production and as model tree in research on air pollution effects on plant physiology. They are generally known to be ozone-sensitive. However, our knowledge of flux-based ozone dose-response (DR) relationships is still limited. According to the meta-analytic review by Prof. Z. Feng (NUIST, China), hybrid poplars may be more sensitive to ozone than non-hybrid ones. An important question has therefore raised if there are different sensitivities to ozone between native poplars and clones. The main objective of this study was to carry out a synthesis of experimental results about the ozone effects on poplars to develop ozone DR relationships for biomass growth reductions using exposure-based (AOT40, Accumulated Ozone exposure over a Threshold of 40 ppb) and flux-based (POD1, Phytotoxic Ozone Dose per leaf area above a threshold of 1 nmol m-2 s-1) indices. According to the result, we calculated a critical level (CL) for a 4% biomass reduction. We summarised literature data (Chinese Open-Top Chamber [OTC] experiments on five hybrid clones) and our own data in previous experimental studies at a Free-Air Controlled Exposure (FACE) and OTCs on hybrid clones (Oxford and I-214) and one non-hybrid European native species (P. nigra). The flux-based POD1 showed a slightly higher R2 value of DR relationships than AOT40 for both hybrid and non-hybrid native poplars. The flux-based CL was 6.6 mmol m-2 POD1 for hybrid poplars while the CL for the non-hybrid native species was 9.5 mmol m-2 POD1, suggesting that non-hybrid native species may be relatively less sensitive to ozone. Those CLs were higher than those previously investigated for the other ozone sensitive species such as beech (Fagus sylvatica L.) and birch (Betula pendula Roth.)(5.2 mmol m-2 POD1). Considering the very high stomatal conductance of poplar species (gmax = 348-575 mmol O3 m-2 PLA s-1), the potential risk of negative impacts for this species should be high.
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