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Distinct responses to ozone of abaxial and adaxial stomata in three Euramerican poplar genotypes

2014; Wiley; Volume: 37; Issue: 9 Linguagem: Inglês

10.1111/pce.12293

1365-3040

Jennifer Dumont, David Cohen, Joëlle Gérard, Yves Jolivet, Pierre Dizengremel, Didier Le Thiec,

Light effects on plants

Abstract Ozone induces stomatal sluggishness, which impacts photosynthesis and transpiration. Stomatal responses to variation of environmental parameters are slowed and reduced by ozone and may be linked to difference of ozone sensitivity. Here we determine the ozone effects on stomatal conductance of each leaf surface. Potential causes of this sluggish movement, such as ultrastructural or ionic fluxes modification, were studied independently on both leaf surfaces of three Euramerican poplar genotypes differing in ozone sensitivity and in stomatal behaviour. The element contents in guard cells were linked to the gene expression of ion channels and transporters involved in stomatal movements, directly in microdissected stomata. In response to ozone, we found a decrease in the stomatal conductance of the leaf adaxial surface correlated with high calcium content in guard cells compared with a slight decrease on the abaxial surface. No ultrastructural modifications of stomata were shown except an increase in the number of mitochondria. The expression of vacuolar H + /Ca 2+ ‐antiports ( CAX 1 and CAX 3 homologs), β‐carbonic anhydrases ( β CA 1 and β CA 4) and proton H + ‐ ATP ase ( AHA 11) genes was strongly decreased under ozone treatment. The sensitive genotype characterized by constitutive slow stomatal response was also characterized by constitutive low expression of genes encoding vacuolar H + /Ca 2+ ‐antiports.