Oxygen and Hydrogen Isotopic Ratios in Plant Cellulose

Epstein, Samuel; Thompson, Peter R.; Yapp, Crayton J.

doi:10.1126/science.198.4323.1209

Cited by 332 publications

(181 citation statements)

References 17 publications

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“…Furthermore, the model cannot account for the observation that the cellulose-water 6180 relationship is the same for tunicates, which produce cellulose nonphotosynthetically, as it is for submerged aquatic plants (7). This model also specifically predicts a one-to-one relationship between cellulose 6180 values and water 6180 values for aquatic plants (11) and is thus at variance with our results. The second model (the carbonyl exchange hypothesis) requires a constant 27%o enrichment during equilibration of carbonyl oxygens with water (7,25).…”

Section: Resultscontrasting

confidence: 56%

“…Due to the lack oftranspiration, the '80/ 160 ratio of tissue water in submerged plants is close to that of the water in which the plant grows (2). This is not the case for terrestrial plants or emergent aquatic plants, which can have leaf water significantly enriched in the heavy isotopes of 0 and H relative to source water due to isotope effects during evapotranspiration (2,11,12,17,19,29 …”

Section: Introductionmentioning

confidence: 99%

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Oxygen-18 Content of Atmospheric Oxygen Does Not Affect the Oxygen Isotope Relationship between Environmental Water and Cellulose in a Submerged Aquatic Plant, Egeria densa Planch

Cooper

DeNiro²

1989

Plant Physiol.

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We determined that the oxygen isotopic composition of cellulose synthesized by a submerged plant, Egeria densa Planch., is related to the isotopic composition of environmental water by a linear function, P80 cellulose = 0.48 6180 water + 24.1%o. The observation of a slope of less than 1 indicates that a portion of cellulose oxygen is derived from an isotopically constant source other than water. We tested whether this source might be molecular oxygen by growing plants in the presence of high concentrations of 180 in the form of 02 bubbled into the bottom of an aquarium. Cellulose synthesized during this experiment did not have significantly different oxygen isotope ratios than that synthesized by control plants exposed to 02 of normal '80 abundance. We propose that oxygen in organic matter recycled from senescent portions of the plant is incorporated into cellulose. Our findings indicate that paleoclimatic models linking the oxygen isotope composition of environmental water to cellulose from fossil plants will have to be modified to account for contributions of oxygen from this or other sources besides water.Based upon experiments with '80-labeled water, Ruben et al. (21) Empirical models have been developed that account for the relationship between 0 isotope ratios of environmental water and cellulose (3,8). However, one of the major assumptions made, that the only source of 0 that affects the 180/1'60 ratios of cellulose is leaf water, may not be true. The evidence concerning the validity of this assumption comes from submerged aquatic plants, which can be used advantageously in studies of the relationship between 0 isotope composition of water and cellulose. Due to the lack oftranspiration, the '80/ 160 ratio of tissue water in submerged plants is close to that of the water in which the plant grows (2). This is not the case for terrestrial plants or emergent aquatic plants, which can have leaf water significantly enriched in the heavy isotopes of 0 and H relative to source water due to isotope effects during evapotranspiration (2,11,12,17,19,29

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Section: Resultscontrasting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Oxygen-18 Content of Atmospheric Oxygen Does Not Affect the Oxygen Isotope Relationship between Environmental Water and Cellulose in a Submerged Aquatic Plant, Egeria densa Planch

Cooper

DeNiro²

1989

Plant Physiol.

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“…Indeed, many mammals obtain all of their water from food. Water in plant roots and stems is isotopically similar to meteoric water, but leaf water is relatively enriched in H 2 18 O due to preferential evapotranspiration of the lighter H 2 16 O molecule (Gonfiantini, Gratziu & Tongiorgi, 1965;Dongmann et al, 1974;Epstein, Thompson & Yapp, 1977;Sternberg, 1989;Yakir, 1992). The isotopic composition of oxygen chemically bound in food is also variable.…”

Section: Introductionmentioning

confidence: 99%

“…The isotopic composition of oxygen chemically bound in food is also variable. For instance, plant leaf cellulose has higher 18 O values than root cellulose, which is generally enriched compared to animal foods (Epstein et al, 1977;Sternberg, 1989;Yakir, 1992;Tredget et al, 1993;Kohn, 1996).…”

Section: Introductionmentioning

confidence: 99%

Oxygen Isotopes in Enamel Carbonate and their Ecological Significance

Sponheimer

Lee‐Thorp

1999

Journal of Archaeological Science

271

142

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“…To date, isotopic values of wood cellulose (Epstein et al, 1977;Yapp and Epstein, 1982;Edwards et al, 1985;Edwards and Fritz, 1986;Roden et al, 2000), grassland phytoliths (Webb and Longstaffe, 2000), and deer bone (Cormie et al, 1994) have been shown to be related to leaf water isotopic composition. Leaf water isotopic signature is not only imprinted on plant organic matter but is also recorded in atmospheric CO 2 and O 2 .…”

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confidence: 99%

18O Spatial Patterns of Vein Xylem Water, Leaf Water, and Dry Matter in Cotton Leaves

et al. 2002

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Three leaf water models (two-pool model, Péclet effect, and string-of-lakes) were assessed for their robustness in predicting leaf water enrichment and its spatial heterogeneity. This was achieved by studying the 18 O spatial patterns of vein xylem water, leaf water, and dry matter in cotton (Gossypium hirsutum) leaves grown at different humidities using new experimental approaches. Vein xylem water was collected from intact transpiring cotton leaves by pressurizing the roots in a pressure chamber, whereas the isotopic content of leaf water was determined without extracting it from fresh leaves with the aid of a purpose-designed leaf punch. Our results indicate that veins have a significant degree of lateral exchange with highly enriched leaf water. Vein xylem water is thus slightly, but progressively enriched in the direction of water flow. Leaf water enrichment is dependent on the relative distances from major veins, with water from the marginal and intercostal regions more enriched and that next to veins and near the leaf base more depleted than the Craig-Gordon modeled enrichment of water at the sites of evaporation. The spatial pattern of leaf water enrichment varies with humidity, as expected from the string-of-lakes model. This pattern is also reflected in leaf dry matter. All three models are realistic, but none could fully account for all of the facets of leaf water enrichment. Our findings acknowledge the presence of capacitance in the ground tissues of vein ribs and highlight the essential need to incorporate Péclet effects into the string-of-lakes model when applying it to leaves.The isotopic composition of leaf water reflects local humidity, and its imprints on plant cellulose and other fossil materials have been widely explored for palaeoclimatic reconstruction. To date, isotopic values of wood cellulose (Epstein et al., 1977;Yapp and Epstein, 1982;Edwards et al., 1985;Edwards and Fritz, 1986;Roden et al., 2000), grassland phytoliths (Webb and Longstaffe, 2000), and deer bone (Cormie et al., 1994) have been shown to be related to leaf water isotopic composition. Leaf water isotopic signature is not only imprinted on plant organic matter but is also recorded in atmospheric CO 2 and O 2 . The CO 2 interacts and undergoes isotopic exchange with leaf water, and O 2 is released by the plant during photosynthesis. Changes in the oxygen isotope ratios of CO 2 and O 2 can thus be used to study variations in the net exchange of CO 2 in terrestrial ecosystems and in the balance of terrestrial and marine productivity (Bender et al., 1985;Bender et al., 1994). Because all of these applications critically depend on estimation of the leaf water oxygen isotopic ratio, a good understanding of the nature of leaf water enrichment is needed.The isotopic composition of leaf water is most commonly estimated from the model of a freely evaporating water surface (Craig and Gordon, 1965) where isotopic fractionation is driven by the lower vapor pressure and diffusivity of the heavier molecules. Although the Craig-Gordon m...

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Oxygen and Hydrogen Isotopic Ratios in Plant Cellulose

Cited by 332 publications

References 17 publications

Oxygen-18 Content of Atmospheric Oxygen Does Not Affect the Oxygen Isotope Relationship between Environmental Water and Cellulose in a Submerged Aquatic Plant, Egeria densa Planch

Oxygen-18 Content of Atmospheric Oxygen Does Not Affect the Oxygen Isotope Relationship between Environmental Water and Cellulose in a Submerged Aquatic Plant, Egeria densa Planch

Oxygen Isotopes in Enamel Carbonate and their Ecological Significance

18O Spatial Patterns of Vein Xylem Water, Leaf Water, and Dry Matter in Cotton Leaves

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