The impact of ozone fumigation and fertilization on chlorophyll fluorescence of birch leaves ( Betula pendula )

Abstract

The impact of ozone fumigation on chlorophyll a fluorescence parameters and chlorophyll content of birch trees grown at high and low fertilization were studied for 6-, 8-, and 12-week old leaves. Fluorescence parameters were measured with a portable fluorometer with its fibre optics tightly inserted in a gas exchange cuvette at light intensities from 0 to 220 µmol photons m −2 s −1 . Ozone caused significant changes of primary photosynthetic reactions: a decrease of the quantum yield of photosystem II and an increase of non-photochemical quenching. In all leaves a biphasic light response of nonphotochemical quenching was observed. Ozone fumigation shifted the onset of the second phase from a PFD of about 60 µmol m −2 s −1 to about 30 µmol m −2 s −1 . While the fertilizer concentration had no influence on this character, high fertilization supply of plants partially reduced O 3 -induced damage. The light responses of Ft, Fm′ and NPQ observed in birch leaves grown in O 3 -free air indicate the existence of at least two different processes governing energy conversion of the photosynthetic apparatus at PS II in the range of PFD 0-200 µmol photons m −2 s −1 . The first phase was attributed to a rather slowly relaxing type of non-photochemical quenching, which, at least at low PFD, is thought to be related to a state 1-2 transition. The further changes of the fluorescence parameters studied at higher PFD might be explained by an increase of energy-dependent quenching, connected with the energization of the thylakoid membrane and zeaxanthin synthesis. A major effect of ozone treatment was a lowering of PS II quantum yield. This reflects a reduction of PS II electron transport and corresponds to the reduction of CO 2 -fixation observed in ozonated leaves.

Growth, photosynthesis and ozone uptake of young beech ( Fagus sylvatica L.) in response to different ozone exposures

“…2). These findings are consistent with those reported in the literature (Reichenauer et al 1997;Shavnin et al 1999).…”

“…Most reports suggest that the carboxylation capacity is the primary target for O 3 damage (Farage et al 1991;Reichenauer et al 1997;Farage and Long 1999;Shavnin et al 1999) and that the primary decrease in photosynthetic rates is due to a loss of Rubisco activity (Farage and Long 1999). In this study Rubisco levels were not measured.…”

Optimum Dark Adaptation Period for Evaluating the Maximum Quantum Efficiency of Photosystem II in Ozone-Exposed Rice Leaves

“…In the present study, the F 0 values recorded in the O 0.1 and O 0.3 plants were generally higher than in the O 0 plants at all measurement times, and the values increased gradually with the progression of dark adaptation (Figures 1(c), (d) and 2(b)). Previous studies in snap bean [20,28] and Betula pendula [24] support the current results that F 0 was increased by O 3 exposure. The increase in F 0 and decrease in F m are induced by the inhibition of electron transport from Q A to Q B and the oxygen-evolving system from the manganese cluster to the tyrosine residue of the D1 protein, respectively [19].…”

Ecophysiological Responses of Northern Birch Forests to the Changing Atmospheric CO2 and O3 Concentrations

“…High O 3 damages chloroplasts (Prozherina et al, 2003;Pääkkönen et al, 1998) and reduces the photosynthetic rate (Mäenpää et al, 2011;Shimizu and Feng, 2007;Uddling et al, 2005;Shavnin et al, 1999). This can be reflected in changes in chlorophyll fluorescence that reveals O 3 stress in photosynthetic pathways (Mao et al, 2012;Wittmann et al, 2007;Shavnin et al, 1999).…”

“…This may lead increased N loss at the whole tree level. On the other hand, ozone reduces the Rubisco concentration (Oksanen, 2005;Yamaji et al, 2003;Oksanen and Rousi, 2001) and the concentration of chlorophyll (Wittmann et al, 2007;Oksanen et al, 2005a;Oksanen and Saleem, 1999;Shavnin et al, 1999) in leaves, which is involved in photosynthesis and consists of N as well as Rubisco. We believe that the allocation pattern of N in a leaf changes and much N is needed for repair of damaged tissue, resulting in impaired photosynthesis.…”