Tree physiology

  • Importance of dry summer for photosynthesis and transpiration of di erent provenances of beech (Fagus sylvatica L.)

European beech (Fagus sylvatica L.) is one of the most important broad-leaved trees in Europe. For a better understanding of the responses of beech to environmental changes the ecophysiological flexibility has to be linked to genetic differences between populations. Different European beech (Fagus sylvatica L.) provenances were investigated at the study site Schädtbek near Kiel (Schleswig-Holstein) during the growing seasons of 2006 and 2007. Aim of the investigation was to study the influence of drought stress on ecophysiological growth parameters and water consumption (photosynthesis, transpiration) under field conditions. Six provenances (2x Germany, Austria, Romania, Spain and Czech Republic) were selected and the diurnal variations of photosynthetic activity (measured as electron transport rate, ETR, effective quantum yield, yield), transpiration (E) and leaf conductance for water vapor (LC) were measured together with environmental factors (light intensity, air temperature and relative air humidity). The comparison of mean values of the parameters studied shows that there are not only between but also within different provenances significant differences between the blocks and between the years. In almost all provenances a positive relationship between the ETR and leaf conductance for water vapor (LC) could be observed. Under consideration of the mean values over all examined trees of the respective blocks this correlation becomes much closer. Evidently, the averaging of values leads to a source-specific value that compensates at least in part the individual variation of the trees. Moreover, there is a close negative relationship between the averages over the blocks of leaf conductance and the saturation deficit of the air. The reduced transpiration leads to significantly higher ratios ETR / E of the provenances from South Eastern Europe compared to those from the north-west and the former seems to react more sensitively to the lower humidity and the reduction of stomata opening minimizes water consumption.Increasing VPD on hot dry days with temperatures above 30 ° C can lead already to a reduction of stomata opening during the diurnal courses, and therefore, on the same day time-shifted measurements at one and the same provenance in different blocks can result to significant different results of the ecophysiological data.Overall, the ecophysiological measurements show the high adaptation and adaptability to climate conditions on the level of populations. Significant differences between populations can be identified on the basis of the measured variables only occasionally and then usually they only affect the extreme values.  Thus, the use of putative better to future climates adapted provenances is to see critical.

Kriebitzsch, W.-U., Veste, M. (2012): Bedeutung trockener Sommer für die Photosynthese und Transpiration von verschiedenen Herkünften der Rotbuche (Fagus sylvatica L.). Landbauforschung 62(4): 193-209.

Kriebitzsch, W.-U., Beck, W., Schmitt, U., Veste, M. (2008): Bedeutung trockener Sommer für Wachstumsfaktoren von verschiedenen Herkünften der Rotbuche (Fagus sylvatica L). AFZ-Der Wald 5/2008: 246-248.

  •  Effect of high level of CO2 on gene expression in two different genotypes of Fagus sylvatica. 
Buche1 (3)

The scenario of a changing environment, widely termed as global change is mainly caused by human activities. Oil and carbon combustion, the use of chlorofluorocarbons, and deforestation are one of the main factors responsible for increasing CO2 concentration and for an increase of air temperature. In addition global changes will affect precipitation patterns, nitrogen concentration in the atmosphere and enhanced UV-B radiation. Forest trees constitute a relevant economic and ecological resource that is under severe pressure by such environmental changes. However, the response of forest trees and in particular of the important forest tree species Fagus sylvatica to elevated CO2 levels on a gene expression basis is unknown so far. The principal aim of this study is the investigation of two different genotypes of Fagus sylvatica upon increased CO2 by microarray and gene expression analyses.

Paffetti, D., Olbrich, M., Fladung, M., Ernst, D., Markussen, T., Forstreuter, M.,  Donnarumma, F.,Kučerová, V., Veste, M., Vettori, C. (2011): Effect of high level of CO2 on gene expression  in two different genotypes of  Fagus sylvatica. BMC Proceedings 2011, 5 (Suppl 7): P171

  • Frost sensitivity and recovery of photosynthesis of the holly Ilex aquifolium L. during winter

The vegetation of Central Europe is relatively poor in evergreen broad-leaved tree species compared to temperate regions of other continents. The holly Ilex aquifolium is one of the few native evergreen broad-leaved trees in Central Europ and extends its range as far north as southern Norway and Sweden. Winter temperature has been pointed out as the most important factor limiting its northern distribution range. The species northern range limit corresponds well with the 0 °C isothermal line of January. In the last decades Ilex aquifolium is expanding its range towards the north  in response to recent climate change. However, the northern distribution range still corresponds with the updated 0 °C isothermal line, indicating rising winter temperatures. Furthermore, a spread of evergreen shrub species including e.g Ilex aquifolium, Hedera helix and the exotic species Prunus laurocerasus and Mahonia aquifolium in temperate broadleaves forests can be observed in Central Europe leading to a laurophyllisation of the forests. In contrast to deciduous species, evergreens may  photosynthesise during mild periods in the winter season. We study the photosynthesis performance and carbon fixation of Ilex during winter. We hypothesise that the evergreen Ilex aquifolium is able to profit from favourable periods in winter and early spring due to enhanced photosynthetic activity.

Berger, S., Veste, M. (2007): Temperature influence on photosynthetic activity of Ilex aquifolium L. - Photosynthetic advantage of climate change? Verhandlungen Gesellschaft für Ökologie 37: 356

Veste, M., Kriebitzsch, W.-U. (2010): Die Stechpalme - ein Gewinner des Klimawandels ?. AFZ-Der Wald 16/2010: 16-18.

Veste, M. (2010): Immergrüne Baumarten erobern neue Lebensräume.  Naturwissenschaftliche Rundschau 63: 

  • Comparative studies of the photosynthesis of three deciduous Nothofagus species from South America. 

Evergreen and deciduous Nothofagus species are the most important trees of the temperate forest in Chile and Argentina. The photosynthetic performance of deciduous Nothofagus species (N. antarctica, N.alpina, N.obliqua) were investigated under similar environmental conditions in a common garden experiment. Chlorophyll fluorescence measurements were carried with a PAM 2100 portable photosynthesis system. The highest electron transport rates of sun- expossed leaves were found in N. antarctica with 135.7 – 187.4 μmol m-2 s-1, while in N. alpina 73.2 – 81.3 μmol m-2 s-1 and N. obliqua 86.2 – 103.7 μmol m-2 s-1. While maximum quantum yield of the photosystem II (Fv/Fm) showed only a small variations among the species. The measured values varied between 0.75 up to 0.78. The photosynthetic performance of the three investigated species correspond with their ecological behavior und with their habitat conditions: N. alpina and N. obliqua are shade tolerant species that growing in depth und good drainage soils, while N. antarctica prefers extreme habitats in open areas with stony or organic soil and with cold, flooding or dry conditions.

Veste, M., Ramirez, C. (2008): Comparative studies of the photosynthesis of three deciduous Nothofagus species from South America. In: Conference EcoNothofagus 2008.  22.-24. April 2008, Esquel, Argentina.

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