Differential response of four tree species to ozone‐induced acceleration of foliar senescence

Abstract

Ozone (O 3 )-induced accelerated senescence of leaves was measured in four tree species: black cherry (Prunus serotina), hybrid poplar (Populus maximowizii x trichocarpa, clone 245), northern red oak (Quercus rubra) and sugar maple (Acer saccharum). Seedlings or ramets of the four species were subjected to chronic O 3 exposures and designated leaves harvested periodically from emergence to senescence. Gas exchange was analysed, and concentrations of total soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase were measured as indicators of leaf senescence. Total antioxidant potential and ascorbate peroxidase and glutathione reductase activities also were determined. Black cherry and hybrid poplar exhibited O 3 -induced accelerated leaf senescence, whereas sugar maple and northern red oak did not. When the O 3 effects were related to cumulative uptake of the gas, black cherry was the most sensitive of the four species. Although hybrid poplar exhibited similar symptoms of O 3 -induced accelerated senescence after the same exposure period as did black cherry, this species took up much greater quantities of O 3 to achieve the same response. The O 3 -induced increase in glutathione reductase activity in hybrid poplar was consistent with the capacity of this species to take up high concentrations of the gas. Relative tolerance of northern red oak and sugar maple could be explained only in part by lower cumulative O 3 uptake and lower rate of uptake. Sugar maple had the highest antioxidant potential of all four species, which may have contributed to O 3 tolerance of this species. Ascorbate peroxidase activity, when expressed on a fresh weight basis, could not account for differential sensitivity among the four species.

Photosynthetic traits of Siebold's beech and oak saplings grown under free air ozone exposure in northern Japan

“…Yonekura et al, 2004). Degradation of Rubisco and chlorophyll, and reabsorption of N from leaves, would take place during this process, as well as normal senescence (Pell et al, 1999;Matyssek and Sandermann, 2003;Oksanen, 2005). In fact, we observed O 3 -induced acceleration of leaf abscission in the following November.…”

New flux based dose–response relationships for ozone for European forest tree species

“…These O 3 effects range from impacts such as visible injury on foliage (Schaub, 2005), decreasing leaf chlorophyll content and photosynthesis (Wittig et al, 2009), changes in carbon allocation (Paoletti et al, 2009) and biomass production (Wittig et al, 2009), premature leaf senescence (Pell et al, 1999), and altered tree water use (Sun et al, 2012). By synthesising information expressed as O 3 flux based doseeresponse relationships (DRR) derived from fieldexperiments, critical levels (CLs) have been identified above which O 3 damage would be expected to occur (LRTAP Convention, 2010;Mills et al, 2011).…”

Differential Effects of Elevated Ozone on Two Hybrid Aspen Genotypes Predisposed to Chronic Ozone Fumigation. Role of Ethylene and Salicylic Acid

“…Chronic O 3 typically decreases net photosynthesis and accelerates foliar senescence in trees (Pell et al, 1999). However, it is not well understood how plants acclimate to chronic O 3 stress.…”