Effectsofthephytotoxicandwidespreadozone(O3)pollutionmaybespeciesspecific,butknowledgeonMediterraneanconiferresponsestolong-termrealisticexposureisstilllimited.Weexaminedresponsesregardingtophotosynthesis,needlebiochemicalstressmarkersandcarbonandnitrogen(N)isotopesoftwoMediterraneanpinespecies(PinushalepensisMill.andPinuspineaL.).SeedlingsweregrowninaFree-AirControlledExposureexperimentwiththreelevelsofO3(ambientair,AA[38.7p.p.b.asdailyaverage];1.5×AAand2.0×AA)duringthegrowingseason(May–October2019).InP.halepensis,O3causedasignificantdecreaseinthephotosyntheticrate,whichwasmainlyduetoareductionofbothstomatalandmesophylldiffusionconductancetoCO2.IsotopicanalysesindicatedacumulativeormemoryeffectofO3exposureonthisspecies,asthenegativeeffectswerehighlightedonlyinthelategrowingseasoninassociationwithareducedbiochemicaldefensecapacity.Ontheotherhand,therewasnocleareffectofO3onphotosynthesisinP.pinea.However,thisspeciesshowedenhancedNallocationtoleavestocompensateforreducedphotosyntheticN-useefficiency.WeconcludethatfunctionalresponsestoO3aredifferentbetweenthetwospeciesdeterminingthatP.halepensiswiththinneedleswasrelativelysensitivetoO3,whileP.pineawiththickerneedleswasmoreresistantduetoapotentiallylowO3loadperunitmassofmesophyllcells,whichmayaffectspecies-specificresilienceinO3-pollutedMediterraneanpineforests.
Functional responses of two Mediterranean pine species in an ozone Free-Air Controlled Exposure (FACE) experiment
Lorenzo Cotrozzi
Secondo
;Cristina Nali;Elisa Pellegrini;Andrea Scartazza;
2023-01-01
Abstract
Effectsofthephytotoxicandwidespreadozone(O3)pollutionmaybespeciesspecific,butknowledgeonMediterraneanconiferresponsestolong-termrealisticexposureisstilllimited.Weexaminedresponsesregardingtophotosynthesis,needlebiochemicalstressmarkersandcarbonandnitrogen(N)isotopesoftwoMediterraneanpinespecies(PinushalepensisMill.andPinuspineaL.).SeedlingsweregrowninaFree-AirControlledExposureexperimentwiththreelevelsofO3(ambientair,AA[38.7p.p.b.asdailyaverage];1.5×AAand2.0×AA)duringthegrowingseason(May–October2019).InP.halepensis,O3causedasignificantdecreaseinthephotosyntheticrate,whichwasmainlyduetoareductionofbothstomatalandmesophylldiffusionconductancetoCO2.IsotopicanalysesindicatedacumulativeormemoryeffectofO3exposureonthisspecies,asthenegativeeffectswerehighlightedonlyinthelategrowingseasoninassociationwithareducedbiochemicaldefensecapacity.Ontheotherhand,therewasnocleareffectofO3onphotosynthesisinP.pinea.However,thisspeciesshowedenhancedNallocationtoleavestocompensateforreducedphotosyntheticN-useefficiency.WeconcludethatfunctionalresponsestoO3aredifferentbetweenthetwospeciesdeterminingthatP.halepensiswiththinneedleswasrelativelysensitivetoO3,whileP.pineawiththickerneedleswasmoreresistantduetoapotentiallylowO3loadperunitmassofmesophyllcells,whichmayaffectspecies-specificresilienceinO3-pollutedMediterraneanpineforests.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
