Photosynthetic Fractionation of Carbon Isotopes

Brugnoli, Enrico; Farquhar, Graham D.

doi:10.1007/0-306-48137-5_17

Cited by 241 publications

(231 citation statements)

References 197 publications

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“…In contrast, carbon in the berries was derived from photosynthesis occurring after veraison when the stress effects were more accentuated. That is, berry tissue may have originated from photoassimilates with a less negative δ 13 C. In addition, the high accumulation of malic acid in the immature berries probably occurs through β-carboxylation of phosphoenolpyruvate by PEP carboxylase (Di Marco et al 1977), which favours 13 C (Farquhar and Richards 1984;Brugnoli and Farquhar 2000).…”

Section: Discussionmentioning

confidence: 99%

Partial rootzone drying: regulation of stomatal aperture and carbon assimilation in field-grown grapevines (Vitis vinifera cv. Moscatel)

Souza¹,

Marôco²,

Santos³

et al. 2003

Functional Plant Biol.

158

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Abstract. The effects of 'partial rootzone drying' (PRD) irrigation compared with other irrigation systems, namely non-irrigated (NI), full irrigation (FI) and deficit irrigation (DI), on stomatal conductance and carbon assimilation were evaluated in field-grown grapevines (Vitis vinifera L. cv. Moscatel). At the end of the growing season, pre-dawn leaf water potential was highest in FI (-0.18 ± 0.01 MPa; mean ± s.e.), intermediate in PRD (-0.30 ± 0.01 MPa) and DI (-0.36 ± 0.02 MPa), and lowest in NI vines (-0.64 ± 0.03 MPa). Stomatal conductance measured under controlled conditions of light and temperature was reduced in NI (ca 60%) and PRD (ca 30%) vines compared with DI and FI vines. Under ambient conditions, NI vines had lower rates of stomatal conductance (ca 26%), net CO 2 assimilation (ca 28%) and light-adapted PSII quantum yields (ca 47%) than PRD, DI and FI vines. No significant differences were found among the three irrigated treatments. Both maximum electron transport rate (J max ; ca 30%) and triose-phosphate utilization rates (TPU; ca 20%) were significantly lower in NI and PRD vines than in DI and FI vines. Carbon isotope composition (δ 13 C) of grape berries was highest in NI vines (-24.3‰), followed by PRD (-25.4‰) and DI (-25.8‰) and lowest in FI (-26.4‰) vines, suggesting a long-term increase in the efficiency of leaf gas exchange in NI compared with PRD, DI and FI vines. Sap-flow data and estimates of relative stomatal limitation are in accordance with the observed stomatal closure in PRD vines. In this study, we show that PRD irrigation was able to maintain a vine water status closed to FI, but with double water use efficiency, which was due to a reduction of stomatal conductance with no significant decrease in carbon assimilation.

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Section: Discussionmentioning

confidence: 99%

Partial rootzone drying: regulation of stomatal aperture and carbon assimilation in field-grown grapevines (Vitis vinifera cv. Moscatel)

Souza¹,

Marôco²,

Santos³

et al. 2003

Functional Plant Biol.

158

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“…10.1), and carboxylation by the enzyme Rubisco (~27‰,b). Discrimination associated with liquid diffusion across membranes to the sites of carboxylation in the chloroplasts is typically lumped into parameter b (Brugnoli and Farquhar 2000;Bickford et al 2010). These processes are captured in Eq.…”

Section: Introductionmentioning

confidence: 99%

Relationships Between Tree Height and Carbon Isotope Discrimination

et al. 2011

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Understanding how tree size impacts leaf-and crown-level gas exchange is essential to predicting forest yields and carbon and water budgets. The stable carbon isotope ratio (d 13 C) of organic matter has been used to examine the relationship of gas exchange to tree size for a host of species because it carries a temporally integrated signature of foliar photosynthesis and stomatal conductance. The carbon isotope composition of leaves reflects discrimination against 13 C relative to 12 C during photosynthesis and is the net result of the balance of change in CO 2 supply and demand at the sites of photosynthesis within the leaf mesophyll. Interpreting the patterns of changes in d 13 C with tree size are not always clear, however, because multiple factors that regulate gas exchange and carbon isotope discrimination (D) co-vary with height, such as solar irradiance and hydraulic conductance. Here we review 36 carbon isotope datasets from 38 tree species and conclude that there is a consistent, linear decline of D with height. The most parsimonious explanation of this result is that gravitational constraints on maximum leaf water potential set an ultimate boundary on the shape and sign of the relationship. These hydraulic constraints are manifest both over the long term through impacts on leaf structure, and over diel periods via impacts on stomatal conductance, photosynthesis and leaf hydraulic conductance. Shading induces a positive offset to the linear decline, consistent with light limitations reducing carbon fixation and increasing partial pressures of CO 2 inside of the leaf, p c at a given height. Biome differences between tropical and temperate forests were more important in predicting D and its relationship to height than wood type associated with being an angiosperm or gymnosperm. It is not yet clear how leaf internal conductance varies with leaf mass area, but some data in particularly tall, temperate conifers suggest that photosynthetic capacity may not vary dramatically with height when compared between tree-tops, while stomatal and leaf internal conductances do decline in unison with height within canopy gradients. It is also clear that light is a critical variable low in the canopy, whereas hydrostatic constraints dominate the relationship between D and height in the upper canopy. The trend of increasing maximum height with decreasing minimum D suggests that trees that become particularly tall may be adapted to tolerate particularly low values of p c .

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“…Successivamente, i campioni sono stati analizzati con uno spettrometro di massa (Finnigan delta S, ThermoQuest, Brema, Germania) per determinare la composizione isotopica del carbonio (δ 13 C) e quindi il rapporto di discriminazione isotopica [ = (δ 13 C aria -δ 13 C foglia )/(1+δ 13 C foglia )], che può essere interpretato come proxy dell'efficienza di uso dell'acqua (Farquhar et al 1982); il δ 13 C dell'aria è stato assunto pari a -8‰ e costante fra i diversi trattamenti (Brugnoli & Farquhar 2000).…”

Section: Campionamentounclassified

Application of isotope discrimination techniques to evaluate the functional response of Mediterranean coppices to high-forest conversion cut

Matteo¹,

Angelis²,

Mugnozza³

2005

Forest@

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Application of isotope discrimination techniques to evaluate the functional response of Mediterranean coppices to high-forest conversion cut.Discrimination of stable isotopes of carbon and hydrogen provides an effective tool for interpreting time-integrated responses of plants to environmental conditions and delineate sources of plant water uptake. In this work, isotopic analyses were carried out in two Mediterranean oak forests in which a thinning experiment on replicated plots has been performed. Changes in carbon isotope discrimination suggests an increase of water use efficiency soon after thinning. Together with changes in the hydrogen isotopic composition in xylem sap, this may suggest that trees are able of a rather prompt physiological acclimation to cope effectively to new environmental conditions and changes in resource availability. Keywords IntroduzioneLa gestione dei boschi cedui nell'area mediterranea, dopo la crisi degli anni '50, si è andata caratterizzando per successivi adattamenti ai mutamenti economici e sociali, sia con adeguamenti del trattamento, sia con la scelta di opzioni colturali diversificate. Queste ultime si sono tradotte nella sospensione delle utilizzazioni, che hanno determinato il cosiddetto "invecchiamento" dei cedui, e nell'avviamento all'alto fusto, che ha interessato sopratutto le zone di proprietà pubblica (Amorini et al. 1996a).L'attuale presenza sul territorio di queste realtà colturali non è ancora consistente, ma la tendenza in atto a valorizzare anche le funzioni non produttive del bosco fa presumere un loro incremento nel prossimo futuro, unitamente ad una revisione complessiva del trattamento selvicolturale delle formazioni di origine agamica. Numerosi studi sono stati focalizzati sugli aspetti tecnici di questa opzione selvicolturale, con importanti applicazioni pratiche sulla gestione forestale pubblica. Per contro, le conoscenze scientifiche dell'impatto dei trattamenti di conversione sulla funzionalità e l'efficienza d'uso delle risorse di questi ecosistemi (efficienza d'uso dell'acqua, efficienza fotosintetica ed efficienza d'uso dell'azoto) sono limitate. Quando, invece, l'opportunità di applicare opzioni gestionali diversificate impone la definizione di tecniche di trattamento fondate sulla valutazione di parametri non solo produttivi ma anche di ordine funzionale.Oggigiorno sono disponibili nuovi strumenti di indagine per studiare la risposta degli alberi e dei popolamenti forestali alla variazione dei fattori ambientali. Tra questi, di particolare rilevanza è l'uso degli isotopi stabili del carbonio e dell'idrogeno, per la loro capacità di integrare nel tempo le risposte a livello di processi fisiologici e per l'idoneità ad essere utilizzati anche in schemi di indagine che prevedano campionamenti intensivi.I valori di discriminazione dell'isotopo stabile del carbonio 13 rispetto al carbonio 12, più abbondante in natura, e del deuterio rispetto all'idrogeno, possono fornire importanti indicazioni, rispettivamente sul rapporto tra assimilazione fot...

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Photosynthetic Fractionation of Carbon Isotopes

Cited by 241 publications

References 197 publications

Partial rootzone drying: regulation of stomatal aperture and carbon assimilation in field-grown grapevines (Vitis vinifera cv. Moscatel)

Partial rootzone drying: regulation of stomatal aperture and carbon assimilation in field-grown grapevines (Vitis vinifera cv. Moscatel)

Relationships Between Tree Height and Carbon Isotope Discrimination

Application of isotope discrimination techniques to evaluate the functional response of Mediterranean coppices to high-forest conversion cut

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