Dynamic carbon allocation into source and sink tissues determine within-plant differences in carbon isotope ratios

2015 ◽  
Vol 42 (7) ◽  
pp. 620 ◽  
Author(s):  
Frederik Wegener ◽  
Wolfram Beyschlag ◽  
Christiane Werner
Keyword(s):  
Nutrient Availability ◽  
Carbon Allocation ◽  
Plant Biomass ◽  
Dark Respiration ◽  
Isotope Composition ◽  
Isotopic Signature ◽  
C3 Plants ◽  
Whole Plant ◽  
Morphological And Physiological Traits ◽  
Allocation Strategies

Organs of C3 plants differ in their C isotopic signature (δ13C). In general, leaves are 13C-depleted relative to other organs. To investigate the development of spatial δ13C patterns, we induced different C allocation strategies by reducing light and nutrient availability for 12 months in the Mediterranean shrub Halimium halimifolium L. We measured morphological and physiological traits and the spatial δ13C variation among seven tissue classes during the experiment. A reduction of light (Low-L treatment) increased aboveground C allocation, plant height and specific leaf area. Reduced nutrient availability (Low-N treatment) enhanced C allocation into fine roots and reduced the spatial δ13C variation. In contrast, control and Low-L plants with high C allocation in new leaves showed a high δ13C variation within the plant (up to 2.5‰). The spatial δ13C variation was significantly correlated with the proportion of second-generation leaves from whole-plant biomass (R2 = 0.46). According to our results, isotope fractionation in dark respiration can influence the C isotope composition of plant tissues but cannot explain the entire spatial pattern seen. Our study indicates a foliar depletion in 13C during leaf development combined with export of relatively 13C-enriched C by mature source leaves as an important reason for the observed spatial δ13C pattern.

scholarly journals Direct soil organic matter compound specific δ13C analysis using pyrolysis (Py-CSIA): identification of biomarkers in a dehesa from Southern Spain

2020 ◽  
Author(s):  
José A. González-Pérez ◽  
Lyla M. San Emeterio ◽  
Francisco J. González-Vila ◽  
María T. Domínguez-Núñez ◽  
José M. de la Rosa
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Mediterranean Climate ◽  
Technical Assistance ◽  
Plant Biomass ◽  
Isotope Composition ◽  
Soil Samples ◽  
C3 Plants ◽  
Analytical Pyrolysis ◽  
Isotopic Characterization

<p>Dehesa are woodlands typical of southern Mediterranean climate species modified by human to seasonal wood-pastures adapted to the unpredictability of the Mediterranean climate. Changes in climatic and environmental conditions can affect both, plant biomass chemical and isotope composition that will eventually be reflected in soil organic matter (SOM). Nowadays, many ecological studies use bulk isotope values, which represent a weighted mean average of the different necromass compounds. An isotopic characterization of individual compounds is desirable to differentiate the isotopic composition of the main plant components. Soil organic matter is composed mainly of high MW biopolymers i.e. polysaccharides, polypeptides, polypeptides, polyesters, etc. not amenable to most chromatographic techniques without the use of intense extraction and sample preparation steps.</p><p>Here, an analytical pyrolysis technique combining Py-GC with a continuous flow isotope ratio mass spectrometer (IRMS) (Py-CSIA) is described and validated for the direct study of compound specific isotope composition in soil samples.</p><p>The consistency of the Py-CSIA was tested using a standard n-alkanes mixture (dissolved C16 to C30 series with increasing concentrations along three pentads, Indiana Univ. SIL mix. Type B). The values obtained fitted to a straight line (R<sup>2</sup> > 0.999). No induced thermal cracking nor deviations from the acclaimed isotope composition (fractionation) was observed up to high pyrolysis temperature (< 500 °C).</p><p>Composite dehesa (Pozoblanco , Córdoba, Spain) surface soil samples were taken under evergreen oak canopy . A detailed SOM study was performed using conventional analytical pyrolysis (Py-GC/MS) and δ<sup>13</sup>C for specific compounds released after pyrolysis was done using Py-CSIA.</p><p>Well-resolved chromatograms were obtained by Py-GC/MS and a total of 40 pyrolysis compounds were detected that represented the chemical variability of soil organic matter and consisted mainly of polysaccharide, lignin-derived compounds (G- and S- units), fatty acids and n-alkanes. When coupling Py with GC-C-IRMS, many c peaks were well resolved and with a sufficient chromatographic separation to give accurate δ<sup>13</sup>C readings. Nonetheless, there were compounds with high δ<sup>13</sup>C standard deviations considered not sufficiently resolved for a reliable estimation of their isotope composition due to coelution and were discarded.</p><p>The δ<sup>13</sup>C for specific biomass compounds released by pyrolysis of soil was in line with the expected values for C3 plants i.e. Quercus spp. Polysaccharide derived products (furans, cyclopentanones), showed slightly enriched δ<sup>13</sup>C values (-26.0 ± 0.47 ‰) in accordance with their naturally <sup>13</sup>C enriched composition. Although no statistical differences were found, lignin-derived units showed slightly depleted δ<sup>13</sup>C ( -27.4 ± 0.78 ‰). Accordingly, depleted δ<sup>13</sup>C values for lipids (-35.1 ± 2.41 ‰) and alkanes (-35.5 ± 2.20 ‰) were found, the latter with lighter isotope composition with increasing the hydrocarbon length.</p><p>Here we show the possibility of using this particular analytical pyrolysis technique (Py-CSIA) for the direct measurement of δ<sup>13</sup>C in relevant specific soil organic matter components including those from polysaccharides (cellulose/hemicellulose), lignin, lipid/waxes and also peptide/protein-derived compounds.</p><p><strong>Acknowledgement:</strong> Ministerio de Ciencia Innovación y Universidades (MICIU) for INTERCARBON project (CGL2016-78937-R) DECAFUN (CGL2015-70123-R). L. San Emeterio also thanks MICIU for funding FPI research grants (BES-2017-07968). Mrs Desiré Monis & Mr Eduardo Gutiérrez González are acknowledged for technical assistance.</p>

scholarly journals Why are non-photosynthetic tissues generally 13C enriched compared with leaves in C3 plants? Review and synthesis of current hypotheses

2009 ◽  
Vol 36 (3) ◽  
pp. 199 ◽  
Author(s):  
Lucas A. Cernusak ◽  
Guillaume Tcherkez ◽  
Claudia Keitel ◽  
William K. Cornwell ◽  
Louis S. Santiago ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Dark Respiration ◽  
Isotope Composition ◽  
General Pattern ◽  
Isotopic Fractionation ◽  
C3 Plants ◽  
Future Research ◽  
Plant Variation ◽  
Developmental Variation ◽  
Isotopic Pattern

Non-photosynthetic, or heterotrophic, tissues in C3 plants tend to be enriched in 13C compared with the leaves that supply them with photosynthate. This isotopic pattern has been observed for woody stems, roots, seeds and fruits, emerging leaves, and parasitic plants incapable of net CO2 fixation. Unlike in C3 plants, roots of herbaceous C4 plants are generally not 13C-enriched compared with leaves. We review six hypotheses aimed at explaining this isotopic pattern in C3 plants: (1) variation in biochemical composition of heterotrophic tissues compared with leaves; (2) seasonal separation of growth of leaves and heterotrophic tissues, with corresponding variation in photosynthetic discrimination against 13C; (3) differential use of day v. night sucrose between leaves and sink tissues, with day sucrose being relatively 13C-depleted and night sucrose 13C-enriched; (4) isotopic fractionation during dark respiration; (5) carbon fixation by PEP carboxylase; and (6) developmental variation in photosynthetic discrimination against 13C during leaf expansion. Although hypotheses (1) and (2) may contribute to the general pattern, they cannot explain all observations. Some evidence exists in support of hypotheses (3) through to (6), although for hypothesis (6) it is largely circumstantial. Hypothesis (3) provides a promising avenue for future research. Direct tests of these hypotheses should be carried out to provide insight into the mechanisms causing within-plant variation in carbon isotope composition.

scholarly journals Wine origin authentication linked to terroir – wine fingerprint

2019 ◽  
Vol 15 ◽  
pp. 02033
Author(s):  
B. Gabel
Keyword(s):  
Pore Water ◽  
Isotope Composition ◽  
Food Product ◽  
Isotopic Signature ◽  
Original Method ◽  
Economic Problem ◽  
Red Wines ◽  
Table Grapes ◽  
Mineral Phases

Global wine and alcohol trade faces a serious economic problem linked to counterfeiting of these commodities. Recently applied authentication methods and techniques pose more difficulties for counterfeiters but they are apparently not effective once we consider economical losses identified by EU legal authorities. The presented solution links isotopic characteristics of the soil, plant, technological intermediate product and the final food product (wine, grapes) on the basis of 87Sr/86Sr isotopes ratios. For the isotopic signature of wines, the average isotope composition of the substrate cannot be a reliable indicator. Only the isotopic composition of pore water can, as it leaches various mineral phases at different stages and passes into vine root system. Instead of complicated sampling of pore water, an original method of preparing and processing soil samples and consequently must & wine samples was developed. Based on both, soil and biological material analysis, we can unquestionably determine not only geographical but also regional and local authenticity of the wine. Determination of red wines isotopic signature is more straightforward process in comparison to white wines, because of technologically different processing of grapes. That is the reason why, in case of white vines, the 87Sr/86Sr ratio of bentonites (natural purifier and absorbent useful in the process of winemaking) must also be taken into consideration. Results of analyses of Slovak wines from geographically diverse regions as well as from sites in close-by distances have clearly established reliability of presented concept, in which the soil is linked to the plant and to the final food product (wine or table grapes).

scholarly journals Ontogenetic shift in the scaling of dark respiration with whole-plant mass in seven shrub species

2009 ◽  
Vol 24 (3) ◽  
pp. 502-512 ◽  
Author(s):  
Youhong Peng ◽  
Karl J. Niklas ◽  
Peter B. Reich ◽  
Shucun Sun
Keyword(s):  
Dark Respiration ◽  
Ontogenetic Shift ◽  
Shrub Species ◽  
Whole Plant

scholarly journals Environmental and taxonomic controls of carbon and oxygen stable isotope composition in <i>Sphagnum</i> across broad climatic and geographic ranges

2018 ◽  
Vol 15 (16) ◽  
pp. 5189-5202 ◽  
Author(s):  
Gustaf Granath ◽  
Håkan Rydin ◽  
Jennifer L. Baltzer ◽  
Fia Bengtsson ◽  
Nicholas Boncek ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Isotope Composition ◽  
Explanatory Power ◽  
Isotopic Signature ◽  
Co2 Uptake ◽  
Δ13c Values ◽  
Site Variation ◽  
Species Specific

Abstract. Rain-fed peatlands are dominated by peat mosses (Sphagnum sp.), which for their growth depend on nutrients, water and CO2 uptake from the atmosphere. As the isotopic composition of carbon (12,13C) and oxygen (16,18O) of these Sphagnum mosses are affected by environmental conditions, Sphagnum tissue accumulated in peat constitutes a potential long-term archive that can be used for climate reconstruction. However, there is inadequate understanding of how isotope values are influenced by environmental conditions, which restricts their current use as environmental and palaeoenvironmental indicators. Here we tested (i) to what extent C and O isotopic variation in living tissue of Sphagnum is species-specific and associated with local hydrological gradients, climatic gradients (evapotranspiration, temperature, precipitation) and elevation; (ii) whether the C isotopic signature can be a proxy for net primary productivity (NPP) of Sphagnum; and (iii) to what extent Sphagnum tissue δ18O tracks the δ18O isotope signature of precipitation. In total, we analysed 337 samples from 93 sites across North America and Eurasia using two important peat-forming Sphagnum species (S. magellanicum, S. fuscum) common to the Holarctic realm. There were differences in δ13C values between species. For S. magellanicum δ13C decreased with increasing height above the water table (HWT, R2=17 %) and was positively correlated to productivity (R2=7 %). Together these two variables explained 46 % of the between-site variation in δ13C values. For S. fuscum, productivity was the only significant predictor of δ13C but had low explanatory power (total R2=6 %). For δ18O values, approximately 90 % of the variation was found between sites. Globally modelled annual δ18O values in precipitation explained 69 % of the between-site variation in tissue δ18O. S. magellanicum showed lower δ18O enrichment than S. fuscum (−0.83 ‰ lower). Elevation and climatic variables were weak predictors of tissue δ18O values after controlling for δ18O values of the precipitation. To summarize, our study provides evidence for (a) good predictability of tissue δ18O values from modelled annual δ18O values in precipitation, and (b) the possibility of relating tissue δ13C values to HWT and NPP, but this appears to be species-dependent. These results suggest that isotope composition can be used on a large scale for climatic reconstructions but that such models should be species-specific.

scholarly journals Ecosystem effects of CO<sub>2</sub> concentration: evidence from past climates

2009 ◽  
Vol 5 (2) ◽  
pp. 937-963 ◽  
Author(s):  
I. C. Prentice ◽  
S. P. Harrison
Keyword(s):  
Forest Cover ◽  
Dissolved Inorganic Carbon ◽  
Net Primary Production ◽  
Isotope Composition ◽  
Late Quaternary ◽  
Co2 Concentration ◽  
C3 Plants ◽  
Sea Level Changes ◽  
Co2 Effects ◽  
Concentration Changes

Abstract. Atmospheric CO2 concentration has varied from minima of 170–200 ppm in glacials to maxima of 280–300 ppm in the recent interglacials. Photosynthesis by C3 plants is highly sensitive to CO2 concentration variations in this range. Physiological consequences of the CO2 changes should therefore be discernible in palaeodata. Several lines of evidence support this expectation. Reduced terrestrial carbon storage during glacials, indicated by the shift in stable isotope composition of dissolved inorganic carbon in the ocean, cannot be explained by climate or sea-level changes. It is however consistent with predictions of current process-based models that propagate known physiological CO2 effects into net primary production at the ecosystem scale. Restricted forest cover during glacial periods, indicated by pollen assemblages dominated by non-arboreal taxa, cannot be reproduced accurately by palaeoclimate models unless CO2 effects on C3-C4 plant competition are also modelled. It follows that methods to reconstruct climate from palaeodata should account for CO2 concentration changes. When they do so, they yield results more consistent with palaeoclimate models. In conclusion, the palaeorecord of the Late Quaternary, interpreted with the help of climate and ecosystem models, provides evidence that CO2 effects at the ecosystem scale are neither trivial nor transient.

Measurements of leaf sucrose to explain variability in hydrogen isotope composition of leaf cellulose

2021 ◽  
Author(s):  
Meisha Holloway-Philips ◽  
Jochem Baan ◽  
Daniel Nelson ◽  
Guillaume Tcherkez ◽  
Ansgar Kahmen
Keyword(s):  
Hydrogen Isotope ◽  
Metabolic Flux ◽  
Species Differences ◽  
Dark Respiration ◽  
Isotope Composition ◽  
Turnover Time ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Model Parameters ◽  
Hydrogen Isotope Composition

&lt;p&gt;The hydrogen isotope composition (&amp;#948;&lt;sup&gt;2&lt;/sup&gt;H) of cellulose has been used to assess ecohydrological processes and carries metabolic information, adding new understanding to how plants respond to environmental change. However, experimental approaches to isolate drivers of &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H variation is limited to the Yakir &amp; DeNiro model (1990), which is difficult to implement and largely unvalidated. Notably, the two biosynthetic fractionation factors in the model, associated with photosynthetic (&amp;#949;&lt;sub&gt;A&lt;/sub&gt;) and post-photosynthetic (&amp;#949;&lt;sub&gt;H&lt;/sub&gt;) processes are currently accepted as constants, and the third parameter &amp;#8211; the extent to which organic molecules exchange hydrogen (f&lt;sub&gt;H&lt;/sub&gt;) with local water &amp;#8211; is usually tuned in order to resolve the difference between modelled and observed cellulose &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H values. Thus, by virtue, the metabolically interpretable parameter is only f&lt;sub&gt;H&lt;/sub&gt;, whilst from theory, metabolic flux rates will also impact on the apparent fractionations. To overcome part of this limitation, we measured the &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H of extracted leaf sucrose from fully-expanded leaves of seven species and a phosphoglucomutase &amp;#8216;starchless&amp;#8217; mutant of tobacco to estimate the isotopic offset between sucrose and leaf water (&amp;#949;&lt;sub&gt;sucrose&lt;/sub&gt;). Sucrose &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H explained ~60% of the &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H variation observed in cellulose. In general, &amp;#949;&lt;sub&gt;sucrose&lt;/sub&gt;&amp;#160;was higher (range: -203&amp;#8240; to -114&amp;#8240;; mean: -151 &amp;#177; 21&amp;#8240;) than the currently accepted value of -171&amp;#8240; (&amp;#949;&lt;sub&gt;A&lt;/sub&gt;) reflecting &lt;sup&gt;2&lt;/sup&gt;H-enrichment downstream of triose-phosphate export from the chloroplast, with statistical differences in &amp;#949;&lt;sub&gt;sucrose&lt;/sub&gt;&amp;#160;observed between species estimates. The remaining &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H variation in cellulose was explained by species differences in f&lt;sub&gt;H&amp;#160;&lt;/sub&gt;(estimated by assuming &amp;#949;&lt;sub&gt;H &lt;/sub&gt;= +158&amp;#8240;). We also tested possible links between model parameters and plant metabolism. &amp;#949;&lt;sub&gt;sucrose&lt;/sub&gt;&amp;#160;was positively related to dark respiration (R&lt;sup&gt;2&lt;/sup&gt;=0.27) suggesting an important branch point influencing sugar &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H. In addition, f&lt;sub&gt;H&lt;/sub&gt; was positively related to the turnover time (&amp;#964;) of water-soluble carbohydrates (R&lt;sup&gt;2&lt;/sup&gt;=0.38), but only when estimated using fixed &amp;#949;&lt;sub&gt;A &lt;/sub&gt;= -171&amp;#8240;. To decipher and isolate the &amp;#8220;metabolic&amp;#8221; information contained within &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H values of cellulose it will be important to assess &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H values of non-structural carbohydrates so that hydrogen isotope fractionation during sugar metabolism can be better understood. This study provides the first attempt at such measurements showing species differences in both source and sink processes are important in understanding &amp;#948;&lt;sup&gt;2&lt;/sup&gt;H variation of cellulose.&lt;/p&gt;

Distinguishing human related, biological, and geological carbon dioxide in the air through isotopic surveying

2021 ◽  
Author(s):  
Giorgio Capasso ◽  
Roberto M.R. Di Martino ◽  
Antonio Caracausi ◽  
Rocco Favara
Keyword(s):  
Carbon Dioxide ◽  
Source Identification ◽  
Isotope Composition ◽  
Strong Dependence ◽  
Landfill Gas ◽  
Molar Fraction ◽  
Data Interpretation ◽  
Isotopic Signature ◽  
Atmospheric Sciences ◽  
Gas Source

&lt;p&gt;Stable isotopes have several applications in geosciences and specifically in volcanology, fluids vs earthquakes studies, environmental surveying, and atmospheric sciences. Both geological and human-related gas sources emit carbon dioxide promoting its molar fraction increase in the lower levels of the atmosphere. The strong dependence of global warming from the carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) concentration in the air promoted the detailed investigation of the sources of CO&lt;sub&gt;2&lt;/sub&gt;. Land use inspection and the correlated increase of air CO&lt;sub&gt;2&lt;/sub&gt; concentration proved often the potential identification of the gas sources. Both the precise identification of the gas source and the specific contribution are still open challenges in environmental surveying. Isotopic signature allows both source identification and tracking fate of carbon dioxide (i.e. natural degassing in volcanic and active tectonic regions, photosynthetic fractionation in tree forests, and human-related emissions in urban zones). The isotopic signature allows evaluating the environmental impact of specific actions and better addressing the mitigation efforts by tracking fate of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&lt;p&gt;This study aims to identify the CO&lt;sub&gt;2&lt;/sub&gt; sources in different ecosystems by using a laser spectrometer that allowed to determine rapidly and with high precision the isotope composition of CO&lt;sub&gt;2&lt;/sub&gt; in the space and/or at high frequency (up to 1Hz). Various environments include both volcanic, seismic and urban zones because of their strong effects on the low levels of the atmosphere were considered, showing how this kind of instruments can disclose new horizons, in many different applications and especially in the time domain. In the considered zones, both the anthropogenic and geological sources caused the increases of CO&lt;sub&gt;2&lt;/sub&gt; molar fraction in the last few centuries. Suitable case studies were: i) the air CO&lt;sub&gt;2&lt;/sub&gt; surveying at Palermo; ii) the soil CO&lt;sub&gt;2&lt;/sub&gt; emissions at Vulcano (Aeolian Islands - Italy), and iii) the punctual vent CO&lt;sub&gt;2&lt;/sub&gt; emissions at Umbertide (Perugia - Italy).&lt;/p&gt;&lt;p&gt;The results of this study show detailed investigation of both sources and fate of the CO&lt;sub&gt;2&lt;/sub&gt; in various environments. The results of the isotope surveying in Palermo show that air CO&lt;sub&gt;2&lt;/sub&gt; correlated with human activities (i.e. house heating, urban mobility, and landfill gas emissions). Comparison with air CO&lt;sub&gt;2&lt;/sub&gt; at Umbertide shows the greater contribution of the geogenic reservoir near the active fault of Alto Tiberina Valley. Volcanic CO&lt;sub&gt;2&lt;/sub&gt; distinguished from biological CO&lt;sub&gt;2&lt;/sub&gt; by different isotopic signature in the soil gases of Vulcano. The soil CO&lt;sub&gt;2&lt;/sub&gt; partitioning at the settled zone of Vulcano Porto occurred through both gas source identification and data interpretation through a specifically designed isotopic mixing model.&lt;/p&gt;&lt;p&gt;This study provides several innovative experimental solutions that are suitable to understand the complexity of carbon cycle and unexplored so far environmental scenarios.&lt;/p&gt;

scholarly journals Whole‐plant optimality predicts changes in leaf nitrogen under variable CO 2 and nutrient availability

2019 ◽  
Vol 225 (6) ◽  
pp. 2331-2346 ◽  
Author(s):  
Silvia Caldararu ◽  
Tea Thum ◽  
Lin Yu ◽  
Sönke Zaehle
Keyword(s):  
Nutrient Availability ◽  
Leaf Nitrogen ◽  
Whole Plant
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