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12. Biogenic volatile organic compound and respiratory CO₂ emissions after ¹³C-labeling: online tracing of C translocation dynamics in poplar plants

Author

Ghirado, A., Gutknecht, J., Zimmer, I., Brüggemann, N., and Schnitzler, J.P.

Subjects
Earth sciences, fungi, ddc:550, food and beverages
Abstract

Background: Globally plants are the primary sink of atmospheric CO2, but are also the major contributor of a large spectrum of atmospheric reactive hydrocarbons such as terpenes (e.g. isoprene) and other biogenic volatile organic compounds (BVOC). The prediction of plant carbon (C) uptake and atmospheric oxidation capacity are crucial to define the trajectory and consequences of global environmental changes. To achieve this, the biosynthesis of BVOC and the dynamics of C allocation and translocation in both plants and ecosystems are important. Methodology: We combined tunable diode laser absorption spectrometry (TDLAS) and proton transfer reaction mass spectrometry (PTR-MS) for studying isoprene biosynthesis and following C fluxes within grey poplar (Populus x canescens) saplings. This was achieved by feeding either 13CO2 to leaves or 13C-glucose to shoots via xylem uptake. The translocation of 13CO2 from the source to other plant parts could be traced by 13C-labeled isoprene and respiratory 13CO2 emission. Principal Finding: In intact plants, assimilated 13CO2 was rapidly translocated via the phloem to the roots within 1 hour, with an average phloem transport velocity of 20.3±2.5 cm h21. 13C label was stored in the roots and partially reallocated to the plants’ apical part one day after labeling, particularly in the absence of photosynthesis. The daily C loss as BVOC ranged between 1.6% in mature leaves and 7.0% in young leaves. Non-isoprene BVOC accounted under light conditions for half of the BVOC C loss in young leaves and one-third in mature leaves. The C loss as isoprene originated mainly (76–78%) from recently fixed CO2, to a minor extent from xylem-transported sugars (7–11%) and from photosynthetic intermediates with slower turnover rates (8–11%). Conclusion: We quantified the plants’ C loss as respiratory CO2 and BVOC emissions, allowing in tandem with metabolic analysis to deepen our understanding of ecosystem C flux.

Published
2011

17. Modeling of annual variations of oak (Quercus-robur L.) isoprene synthase activity to predict isoprene emission rates

Author

Lehning, A., Zimmer, W., Zimmer, I., Schnitzler, J.P., and Publica

Abstract

Isoprene plays an important role in regulating the atmospheric trace gas composition, in particular the tropospheric ozone concentrations. Therefore realistic estimates of the seasonal variation of isoprene emission source strengths of strong isoprene-emitting deciduous trees such as pedunculate oak (Quercus robur L.) are required in temperate regions of Europe. In 1995 to 1997 a study was conducted to survey the annual fluctuations of oak isoprene synthase activity and photosynthetic pigment contents, the latter as a parameter for the development of the photosynthetic apparatus of oak leaves. Depending on annual temperature and light profiles (photosynthetic photon flux densities (PPFD)), different seasonal patterns of isoprene synthase activity were observed with maximum activities of 18.4 +/- 10.6 nmol m(-2),14.1 +/- 5.8 nmol m(-2) s(-1), and 19.9 +/- 7.9 nmol m(-2) s-(1) in 1995, 1996, and 1997, respectively. On the basis of isoprene synthase activity, chlorophyll a measurements, and phenological data collected from pedunculate oaks of 89 ecological regions covering all of Germany a model was developed for the calculation of the seasonal variation of oak isoprene synthase activity in relation to annual fluctuation of temperature and PPFD. By coupling this model to a numeric process-based isoprene emission model it was possible to predict isoprene emission rates of individual pedunculate oak trees with a deviation of 55%.

Published
2001

18. Isoprene synthase activity and its relation to isoprene emission in Quercus robur L. leaves

Author

Lehning, A., Zimmer, I., Steinbrecher, R., Brüggemann, N., Schnitzler, J.-P., and Publica

Subjects
enzyme capacity, isoprene emission, isoprene synthase activity, Quercus robur, leaf development
Abstract

Pedunculate oak (Quercus robur L.) is known as a strong isoprene (2-methyl-1,3-butadiene) emitter. Diurnal changes in isoprene emission were determined by branch enclosure measurements. In contrast to the diurnal cycle in emission rates, specific isoprene synthase activity in the leaves remained unchanged. Based on in vitro enzyme activity and its temperature dependency, an isoprene synthesis capacity at specific leaf temperatures was calculated. The comparison of these 'leaf temperature-dependent enzyme capacities' and the measured emission rates revealed that the enzyme activity of isoprene synthase is comparable to the observed isoprene emission rates. In addition, variation in the isoprene synthase activity of the leaves due to changes in light intensity during leaf development was investigated. A 50% reduction of light intensity by shading of single branches reduced isoprene synthase activity by = 60 % compared with full sunlight. The calculation of isoprene synthesis capacities based on enzymatic data obtained under optimum reaction conditions, corrected for actual leaf temperature and related to leaf surface area, provides a sound basis for predicting the isoprene emission potential of plants.

Published
1999

21. All at sea with animal tracks; methodological and analytical solutions for the resolution of movement

Author

Wilson, R, Liebsch, N, Davies, I, Quintana, F, Weimerskirch, H, Storch, S, Lucke, K, Siebert, U, Zankl, S, Muller, G, Zimmer, I, Scolaro, A, Campagna, C, Plotz, J, Bornemann, H, Teilmann, J, McMahon, Clive, Wilson, R, Liebsch, N, Davies, I, Quintana, F, Weimerskirch, H, Storch, S, Lucke, K, Siebert, U, Zankl, S, Muller, G, Zimmer, I, Scolaro, A, Campagna, C, Plotz, J, Bornemann, H, Teilmann, J, and McMahon, Clive

Abstract

Determining the movement of marine animals is logistically difficult and is currently primarily based on VHF and satellite-tracking telemetry, GPS, acoustic telemetry, and geolocation, all of which have substantial limitations in accurately locating the fine-scale movements of these animals. A recent development—that of dead-reckoning—is being increasingly used to examine the fine-scale movement of animals underwater. The advantages and drawbacks of this approach are quite different to those incurred by the other methods. This paper considers the advances that dead-reckoning can bring to the study of the often cryptic movement and behaviour of marine animals at sea. Methods used in determining position via dead-reckoning are presented and consideration is given to results derived from the use of deadreckoning on cetaceans, pinnipeds, penguins and sea turtles; these are complemented by data on cormorants and albatrosses acquired using GPS systems. Suggestions are made as to how movement data derived from these devices can be analysed using indices that allow interpretation over a large variety of temporal and spatial scales.

Published
2007

22. How do Magellanic Penguins cope with variability in their access to prey?

Author

Wilson, Rory P., Scolaro, A., Gremillet, D., Kierspel, Mandy, Laurenti, S., Upton, J., Gallelli, H., Quintana, F., Frere, E., Müller, G., Thor Straten, M., Zimmer, I., Wilson, Rory P., Scolaro, A., Gremillet, D., Kierspel, Mandy, Laurenti, S., Upton, J., Gallelli, H., Quintana, F., Frere, E., Müller, G., Thor Straten, M., and Zimmer, I.

Abstract

Movements of animals provisioning offspring by central place foraging extend from short, highly local trips where food is brought back essentially unchanged from its normal condition to extensive interseasonal movement where the offspring are nourished from body reserves built up during the adult's absence from the breeding site. Here, appropriate strategies for maximizing lifetime reproductive success depend on the abundance and location of prey in relation to breeding sites and the energetics and speed of travel of the animal. Magellanic Penguins Spheniscus magellanicus undertake central place movements that are particularly variable during the incubation period; trips may last from a single day to over three weeks depending on colony locality. We reasoned that site-specific variability in prey distribution and abundance is responsible for this. Remote-sensing systems attached to 92 penguins from six different colonies over the species distributional range over the Patagonian Shelf were used to determine space use and foraging patterns in an attempt to understand the observed patterns. Birds in the north and south of the latitudinal range were essentially monophagic, feeding primarily on anchovies Engraulis anchoita and sprats Sprattus fuegensis, respectively, both species that are to be found relatively close to the colonies. Penguins in the center of the distributional range, where these pelagic school fish prey are essentially absent at that time of the year, traveled either north or south, to the same regions utilized by their conspecifics, presumably to exploit the same prey. A simple model is used to clarify patterns and can be used to predict which movement strategy is likely to be best according to colony location. During chick rearing, southerly movement of anchovies and northerly movement of sprats mean that Magellanic Penguins in the center of the distributional range may benefit, although the abundance of these fish is considered to be less than that c

Published
2005
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37. Evidence of the three main clonal Toxoplasma gondii lineages from wild mammalian carnivores in the UK.

Author

BURRELLS, A., BARTLEY, P. M., ZIMMER, I. A., ROY, S., KITCHENER, A. C., MEREDITH, A., WRIGHT, S. E., INNES, E. A., and KATZER, F.

Subjects
TOXOPLASMA gondii, CARNIVOROUS animals, CLONE cells, ZOONOSES, PATHOGENIC microorganisms, POLYMERASE chain reaction, RESTRICTION fragment length polymorphisms
Abstract

Toxoplasma gondii is a zoonotic pathogen defined by three main clonal lineages (types I, II, III), of which type II is most common in Europe. Very few data exist on the prevalence and genotypes of T. gondii in the UK. Wildlife can act as sentinel species for T. gondii genotypes present in the environment, which may subsequently be transmitted to livestock and humans. DNA was extracted from tissue samples of wild British carnivores, including 99 ferrets, 83 red foxes, 70 polecats, 65 mink, 64 badgers and 9 stoats. Parasite DNA was detected using a nested ITS1 PCR specific for T. gondii, PCR positive samples were subsequently genotyped using five PCR–RFLP markers. Toxoplasma gondii DNA was detected within all these mammal species and prevalence varied from 6·0 to 44·4% depending on the host. PCR–RFLP genotyping identified type II as the predominant lineage, but type III and type I alleles were also identified. No atypical or mixed genotypes were identified within these animals. This study demonstrates the presence of alleles for all three clonal lineages with potential for transmission to cats and livestock. This is the first DNA-based study of T. gondii prevalence and genotypes across a broad range of wild British carnivores. [ABSTRACT FROM AUTHOR]

Published
2013
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38. Inter- and intra-specific variability in isoprene production and photosynthesis of Central European oak species.

Author

Steinbrecher, R., Contran, N., Gugerli, F., Schnitzler, J.‐P., Zimmer, I., Menard, T., Günthardt‐Goerg, M.S., and Loreto, F.

Subjects
PHOTOSYNTHESIS, ISOPRENE, OAK, PLANT species, ISOPENTENOID synthesis, SEEDLINGS, PLANT variation, CENTRAL Europeans
Abstract

European deciduous oaks are closely related and are known for their strong emission of volatile isoprenoids. They are chemo-taxonomically diverse, but hybridise frequently. Four-year-old oak seedlings growing together in a model ecosystem facility under near-natural conditions were studied. The leaves were morphologically classified in the three oak species Quercus robur, Q. pubescens and Q. petraea (with four provenances each) and further investigated by a molecular-genetic approach. Q. robur was morphologically and genetically clearly different from Q. pubescens and Q. petraea, whereas Q. pubescens and Q. petraea individuals used in this study were morphologically and genetically more similar. There was a minor impact of among and within species variability on isoprene synthesis, isoprene emission and photosynthesis. Isoprene emission rates normalised to 25 °C leaf temperature ranged from 5.78 to 10.66 nmol m−2 s−1, whereas photosynthesis ranged from 12.8 to 17.6 μmol m−2 s−1. On cloudy days, among the provenances of each species, only net photosynthesis of the Q. robur provenance Hünenberg was reduced and isoprene synthase activity of the Q. pubescens provenance Promotogno increased. On sunny days, photosynthesis did not differ among the provenances. Over all provenances, gas exchange on cloudy days did not differ significantly from sunny days. In the combined data of cloudy and sunny days, no differences between the studied provenances and oak species were detected in isoprene emission and photosynthesis. Thus, isoprene emission and photosynthesis rates were remarkably stable among oak species and provenances. The results indicate that taxonomic differences in the studied oak species are not reflected in isoprene emission and photosynthesis, probably because of the high plasticity of gene expression resulting in high phenotypic flexibility. [ABSTRACT FROM AUTHOR]

Published
2013
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39. Drought reduced monoterpene emissions from the evergreen Mediterranean oak Quercus ilex: results from a throughfall displacement experiment.

Author

Lavoir, A.-V., Staudt, M., Schnitzler, J. P., Landais, D., Massol, F., Rocheteau, A., Rodriguez, R., Zimmer, I., and Rambal, S.

Subjects
DROUGHTS, MONOTERPENES, EMISSIONS (Air pollution), EVERGREENS, ORGANIC compounds
Abstract

The effects of water limitations on the emission of biogenic volatile organic compounds are not well understood. Experimental approaches studying drought effects in natural conditions are still missing. To address this question, a throughfall displacement experiment was set up in a natural forest of Quercus ilex, an evergreen Mediterranean oak emitting monoterpenes. Mature trees were exposed in 2005 and 2006 either to an additional drought, to irrigation or to natural drought (untreated control). In both years, absolute monoterpene emission rates as well as the respective standard factors of the trees exposed to normal and additional drought strongly declined during the drought periods. Monoterpene emissions were lower in year 2006 than in year 2005 (factor 2) due to a more pronounced summer drought period in this respective year. We observed a significant difference between the irrigation and additional drought or control treatment: irrigated trees emitted 82% more monoterpenes during the drought period 2006 than the trees of the other treatments. However, no significant effect on monoterpene emission was observed between normal and additional drought treatments, despite a significant effect on leaf water potential and photochemical efficiency. During the development of drought, monoterpene emissions responded exponentially rather than linearly to decreasing leaf water potential. Emissions rapidly declined when the water potential dropped be- low -2MPa and photosynthesis was persistently inhibited. Monoterpene synthase activities measured in vitro showed no clear reduction during the same period. From our results we conclude that drought significantly reduces monoterpene fluxes of Mediterranean Holm oak forest into the atmosphere due to a lack of primary substrates coming from photosynthetic processes. [ABSTRACT FROM AUTHOR]

Published
2009
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40. Drought reduced monoterpene emissions from Quercus ilex trees: results from a throughfall displacement experiment within a forest ecosystem.

Author

Lavoir, A. V., Staudt, M., Schnitzler, J. P., Landais, D., Massol, F., Rocheteau, A., Rodriguez, R., Zimmer, I., and Rambal, S.

Subjects
VOLATILE organic compounds & the environment, MONOTERPENES, FOREST restoration, HOLM oak, PHOTOSYNTHESIS, PHOTOCHEMISTRY
Abstract

The effects of water limitations on the emission of biogenic volatile organic compounds are not well understood. Experimental approaches studying drought effects in natural conditions are still missing. To address this question, a throughfall displacement experiment was set up in a natural forest of Quercus ilex, an evergreen Mediterranean oak emitting monoterpenes. Mature trees were exposed in 2005 and 2006 either to an additional drought, to irrigation or to natural drought (untreated control). In both years, absolute monoterpene emission rates as well as the respective standard factors of the trees exposed to normal and additional drought strongly declined during the drought periods. Monoterpene emissions were lower in year 2006 than in year 2005 (factor 2) due to a more pronounced summer drought period in this respective year. We observed a significant difference between the irrigation and additional drought or control treatment: irrigated trees emitted 82% more monoterpenes during the drought period 2006 than the trees of the other treatments. However, no significant effect on monoterpene emission was observed between normal and additional drought treatments, despite a significant effect on leaf water potential and photochemical efficiency. During the development of drought, monoterpene emissions responded exponentially rather than linearly to decreasing leaf water potential. Emissions rapidly declined when the water potential dropped below -2MPa and photosynthesis was persistently inhib ited. Monoterpene synthase activities measured in vitro showed no clear reduction during the same period. From our results we conclude that drought significantly reduces monoterpene fluxes of Mediterranean evergreen forest into the atmosphere due to a sustained inhibition of photosynthetic carbon assimilation. [ABSTRACT FROM AUTHOR]

Published
2009
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