Tree age dependence and within-canopy variation of leaf gas exchange and antioxidative defence in Fagus sylvatica under experimental free-air ozone exposure

Elevated ozone negatively affects photosynthesis of current-year leaves but not previous-year leaves in evergreen Cyclobalanopsis glauca seedlings

“…Fares et al (2010) found that a changing defense against O 3 along the plant axis in Populus nigra was attributed to a vertical profile of foliar phenolic and volatile compounds. In accordance with their study, concentrations of antioxidants and secondary products were observed higher in sun leaves or upper canopy foliage of Fagus sylvatica L., including significantly increased glutathione concentrations under double O 3 concentration across both age classes and canopy levels (Herbinger et al, 2005).…”

“…Therefore, lower A sat and g s at ML may also be a result of adaptation or acclimation of plants to high [O 3 ]. The variation of g s from the apex along the vertical plant axis has been suggested to correspond with the degree of shading and age of the leaves (Herbinger et al, 2005;Kitao et al, 2006;Paoletti and Grulke, 2005).…”

Deciphering the ozone-induced changes in cellular processes: a prerequisite for ozone risk assessment at the tree and forest levels

“…Total glutathione and/or reduced glutathione content generally increased in leaves of tree species under O 3 fumigation (100 to 120 ppb) (Dumont et al 2014;Wellburn et al 1996). In adult beech trees, the glutathione level is affected by canopy position, but O 3 exposure (twofold ambient concentration) involved higher content in both shade and sun leaves (Herbinger et al 2005). In some works, the differences in the constitutive levels of glutathione between poplar genotypes appeared to contribute to the higher tolerance to chronic O 3 exposure (Di Baccio et al 2008;Dumont et al 2014).…”

Disturbances in European beech water relation during an extreme drought

“…Similar behaviour had previously been reported at the canopy level for canopy conductance related to water vapour variation (Granier et al 2000(Granier et al , 2002(Granier et al , 2007and Bréda et al 2006). In our study, under high soil water availability, stomatal conductance values were significantly different for sun-exposed leaves located at 14-m height and shaded leaves at 10 m= 240 vs. 71 mmol m and 25 mmol m −2 s −1 in Herbinger et al (2005). On the other hand, when soil water was greatly depleted, i.e.…”

“…Many studies have also reported that, as a rule, leaf position within the crown determines physiological and anatomical leaf traits (Aussenac and Ducrey 1977). In European beech trees, stomatal conductance increases from the base to the top of the crown (Aranda et al 2000, Cochard et al 1999, Herbinger et al 2005Lemoine et al 2002a;Wieser et al 2003), whilst diurnal leaf water potential decreases (Aranda et al 2000;Lemoine et al 2002a, b). Leaf morphology and leaf orientation also show adaptations: leaf mass area increases from the base to the top of the crown (Peiffer 2005;Montpied et al 2009), whilst leaf angle becomes more vertical (Planchais and Sinoquet 1998).…”