Beech trees exposed to high CO₂ and to simulated summer ozone levels: Effects on photosynthesis, chloroplast components and leaf enzyme activity

Abstract

Young trees of European beech (Fagus syl7atica L.) were phate carboxylase/oxygenase activity, while the summer and exposed in a phytotron to different levels of ozone and CO 2 early autumn harvests showed strong reductions in these under the climatic simulation of one vegetation period. High parameters. Only phosphoenolpyruvate carboxylase (PEPozone levels were simulated similar to high ozone concentra-case) activity remained higher under high ozone. The effects of high CO 2 appeared in general as a small stimulation in tion in the field (up to 110 ppb), while CO 2 was added as 300 ppm to the present level of ca 380 ppm. Our study describes enzyme activity like PEPcase in spring. However, with indifferent aspects of photosynthesis from the leaf level to the creasing time of fumigation, reductions of all parameters were observed. Especially chlorophylls showed strong reduc-reactions of selected thylakoid components at different hartions under high CO 2 . The combined treatment with high vest times during growth of the beech trees under the different fumigation regimes. Ozone effects appeared in the first weeks ozone plus high CO 2 resulted mostly in an amelioration of the of the treatment as a stimulation of chlorophyll fluorescence negative ozone effects, although control levels were not (F v /F m ), in oxygen production and in ribulose-1,5-bisphos-reached.

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

“…Similarly, in Aleppo pine, both Rubisco and Rubisco activase levels were reduced under O 3 (Pelloux et al 2001). In angiosperms also, multiple works supported the idea of O 3 -driven alteration of Rubisco activity (Gaucher et al 2003;Lutz et al 2000;Matyssek et al 1991;Pell et al 1992). However, it remains unclear whether the decrease in Rubisco activity is due to enhanced degradation, ROS-mediated protein oxidation, decreased Rubisco activase activity or altered gene expression (Brendley and Pell 1998;Dizengremel 2001;Heath 2008;Pell et al 1994).…”

Response of gas exchange and yield components of field-grown Triticum aestivum L. to elevated ozone in China

“…In this scenario, comparatively high peak of O 3 concentration did not accompany the highest PPFD, thus O 3 went into mesophyll cells through stomata easily. Once O 3 entered into mesophyll, it severely damaged the structure and function of photosynthetic organ (Lütz et al 2000), and was accompanied by a series of physiological and biochemical characters altering in plant, such as an increase of membrane permeability, protein decomposition, and lipid peroxidation (Jin et al 2000, Lütz et al 2000, Płażek et al 2000, Calatayud et al 2004). Therefore, a significant decrease in P N was found in additional O 3 treatment (CF+O 3 ), which was also observed by Meyer et al (2000) under two different O 3 concentration peak regimes.…”

Growth and physiological responses to ozone and mild drought stress of tree species with different ecological requirements

“…Other studies, however, highlight the role of the enzyme phosphoenol pyruvate carboxylase (PEPc), which has a greater affinity for 13 C than ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). The production and the activity of these enzymes are stimulated, both in C3 and C4 plants, by a variety of stressors, including drought stress and ozone (Freyer 1979;Martin et al 1988;Matyssek et al 1992;Singh-Sangwan et al 1994;Saurer et al 1995;Lütz et al 2000;Fontaine et al 2003;Gaucher et al 2004;Inclan et al 2005;Novak et al 2007).…”