Carbon isotope discrimination of C3 vegetation in Central Asian Grassland as related to long-term and short-term precipitation patterns

Abstract. The relationship between carbon isotope discrimination (13Δ) of C3 vegetation and long-term (30 years) and short-term (growing period) precipitation was investigated. Members of Stipa, a dominant grass genus in the (semi-)arid Asian steppes, and other C3 species were collected along aridity gradients in Inner Mongolia in 2005 (11 sites, 71 samples) and in the Republic of Mongolia in 2006 (40 sites, 45 samples). The data set was expanded with published and unpublished data of Stipa and other C3 species (11 studies covering 8 years, including 64 observations of Stipa, and 103 observations of other C3 species) and C3 community bulk-samples (11 samples). Weather data were geostatistically interpolated for all sampling sites and years. 13Δ of Stipa followed different relationships for the individual years when related to mean annual precipitation due to large anomalies between annual and long-term average precipitation patterns. But, the 13Δ response to rainfall converged when mean annual precipitation was replaced by year-specific mean daily growing period precipitation (PG). Remarkably, the 13Δ-response to PG for C3 species as a whole (including herbaceous dicots, semi-shrubs and grasses) and also the C3 community-level response were virtually identical to that of Stipa. The relation was also valid outside the geographical and climatic range where it was developed, giving proof of its robustness.

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Carbon isotope discrimination of C3 vegetation in Central Asian grassland as related to long-term and short-term precipitation patterns

Biogeosciences ◽

10.5194/bg-5-913-2008 ◽

2008 ◽

Vol 5 (3) ◽

pp. 913-924 ◽

Cited By ~ 28

Author(s):

M. H. O. M. Wittmer ◽

K. Auerswald ◽

R. Tungalag ◽

Y. F. Bai ◽

R. Schäufele ◽

...

Keyword(s):

Carbon Isotope ◽

Carbon Isotope Discrimination ◽

Annual Precipitation ◽

Mean Annual Precipitation ◽

Short Term ◽

Isotope Discrimination ◽

Precipitation Patterns ◽

Growing Period ◽

C3 Species

Abstract. The relationship between carbon isotope discrimination (13Δ) of C3 vegetation and long-term (30 years) and short-term (growing period) precipitation was investigated. Different species of Stipa, a dominant grass genus in the (semi-)arid Asian steppes, and other C3 species were collected along aridity gradients in Inner Mongolia in 2005 (11 sites, 71 samples) and in the Republic of Mongolia in 2006 (40 sites, 45 samples). The data set was expanded with published and unpublished data of Stipa and other C3 species (11 studies covering 8 years, including 64 observations of Stipa, and 103 observations of other C3 species) and C3 community bulk-samples (11 samples). Weather data were geostatistically interpolated for all sampling sites and years. 13Δ of Stipa followed different relationships for the individual years when related to mean annual precipitation due to large anomalies between annual and long-term average precipitation patterns. However, the 13Δ response to rainfall converged when the (long-term) mean annual precipitation was replaced by year-specific mean daily precipitation during the growing period (PG). Remarkably, the 13Δ-response to (PG) for C3 species as a whole (including herbaceous dicots, semi-shrubs and grasses) and also the C3 community-level response were virtually identical to that of Stipa. The relation was also valid outside the geographical and climatic range where it was developed, giving proof of its robustness.

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Correlation between carbon isotope discrimination and transpiration efficiency in lines of the C4 species Sorghum bicolor in the glasshouse and the field

Functional Plant Biology ◽

10.1071/pp95033 ◽

1998 ◽

Vol 25 (1) ◽

pp. 111 ◽

Cited By ~ 42

Author(s):

S. Henderson ◽

S. von Caemmerer ◽

G.D. Farquhar ◽

L. Wade ◽

G. Hammer

Keyword(s):

Sorghum Bicolor ◽

Carbon Isotope ◽

Carbon Isotope Discrimination ◽

Negative Slope ◽

Environment Interaction ◽

Transpiration Efficiency ◽

Isotope Discrimination ◽

C4 Species ◽

C3 Species ◽

The Mean

Transpiration efficiency, W, the ratio of plant carbon produced to water transpired and carbon isotope discrimination of leaf dry matter, Δd, were measured together on 30 lines of the C4 species, Sorghum bicolor, in the glasshouse and on eight lines grown in the field. In the glasshouse, the mean W observed was 4.9 mmol C mol-1 H2O and the range was 0.8 mmol C mol -1 H2O. The mean Δd was 3.0 and the observed range was 0.4‰. In the field, the mean W was lower at 2.8 mmol C mol-1 H2O and the mean Δd was 4.6‰. Significant positive correlations between W and Δd were observed for plants grown in the glasshouse and in the field. The observed correlations were consistent with theory, opposite to those for C3 species, and showed that variation in Δd was an integrated measure of long-term variation in the ratio of intercellular to ambient CO2 partial pressure, pi/pa. Detailed gas exchange measurements of carbon isotope discrimination during CO2 uptake, ΔA, and pi/pa were made on leaves of eight S. bicolorlines. The observed relationship between ΔA and pi/pa was linear with a negative slope of 3.7‰ in ΔA for a unit change in pi/pa. The slope of this linear relationship between ΔA and pi/pa in C4 species is dependent on the leakiness of the CO2 concentrating mechanism of the C4 pathway. We estimated the leakiness (defined as the fraction of CO2 released in the bundle sheath by C4 acid decarboxylations, which is lost by leakage) to be 0.2. We conclude that, although variation in Δd observed in the 30 lines of S. bicolor is smaller than that commonly observed in C3 species, it also reflects variation in transpiration efficiency, W. Among the eight lines examined in detail and in the environments used, there was considerable genotype × environment interaction.

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Short-term changes in carbon-isotope discrimination in the C3-CAM intermediate Clusia minor L. growing in Trinidad

Oecologia ◽

10.1007/bf00321001 ◽

1993 ◽

Vol 95 (3) ◽

pp. 444-453 ◽

Cited By ~ 35

Author(s):

A. M. Borland ◽

H. Griffiths ◽

M. S. J. Broadmeadow ◽

M. C. Fordham ◽

C. Maxwell

Keyword(s):

Carbon Isotope ◽

Carbon Isotope Discrimination ◽

Short Term ◽

Isotope Discrimination

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Short-Term Measurements of Carbon Isotope Discrimination in Several C4 Species

Functional Plant Biology ◽

10.1071/pp9920263 ◽

1992 ◽

Vol 19 (3) ◽

pp. 263 ◽

Cited By ~ 121

Author(s):

SA Henderson ◽

SV Caemmerer ◽

GD Farquhar

Keyword(s):

Carbon Isotope ◽

Carbon Isotope Discrimination ◽

Isotope Composition ◽

Leaf Gas Exchange ◽

Short Term ◽

Isotope Discrimination ◽

C4 Species ◽

Linear Relationships ◽

Partial Pressures ◽

Wide Range

Carbon isotope discrimination (Δ) and leaf gas-exchange were measured simultaneously for a number of C4 species. Linear relationships were found between A and the ratio of intercellular to ambient partial pressures of CO2, pI/pa. These data were used to estimate the fraction of CO2 released by C4-acid decarboxylation in the bundle sheath, which subsequently leaks out to the mesophyll. We define this fraction as the leakiness of the system and it is also a measure of the extent to which phosphoenolpyruvate (PEP) carboxylations exceed ribulose 1,5-bisphosphate (RuBP) carboxylations. For Sorghum bicolor and Amaranthus edulis, leakiness was estimated at 0.2 and was constant over a wide range of irradiances (between 480 and 1600 μmol quanta m-2 s-1), intercellular CO2 pressures (between 30 and 350 μbar) and leaf temperatures (from 21�C to 34�C). At irradiances less than 240 μmol quanta m-2 s-1, leakiness appeared to increase. For a number of dicotyledonous and monocotyledonous species, of the various C4-decarboxylation types, leakiness was also estimated at 0.2. Contrary to expectation, amongst the 11 species examined, those with suberised lamellae did not show lower values of leakiness than those without suberised lamellae. For one NAD-ME and one PCK monocot, the estimates of leakiness were significantly higher at 0.30 and 0.25, respectively. Long-term discrimination (assessed from carbon isotope composition of leaf dry matter) did not correlate well with these short- term measures of discrimination. We suggest that this may be due to differences between species in fractionations occurring after photosynthesis.

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