Genetic variation in carbon isotope discrimination and its relationship to growth under field conditions in full-sib families of Piceamariana

1995 ◽  
Vol 25 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Lawrence B. Flanagan ◽  
Kurt H. Johnsen
Keyword(s):  
Genetic Variation ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Leaf Tissue ◽  
Tree Height ◽  
Strong Negative Correlation ◽  
Isotope Discrimination ◽  
Sib Families

Measurements of the stable carbon isotope composition of leaf tissue were made on Piceamariana (Mill.) B.S.P trees from four full-sib families grown on three different field sites at the Petawawa National Forestry Institute, Ontario, Canada. The four families chosen exhibited genetic variation for growth characteristics. Genetic variation was also observed for carbon isotopic discrimination (Δ) among the families of P. mariana. In addition, a strong correlation occurred between Δ values measured on trees in 1991 and 1992, two years that had very different precipitation and temperature conditions during the growing season, indicating that the ranking of individual trees remained almost constant between years. A strong, negative correlation was observed between average carbon isotope discrimination and average tree height for the four families on the driest, least productive site, as was expected based on leaf photosynthetic characteristics. There was no significant correlation, however, between Δ values and growth on the other two study sites, where productivity was higher.

On the extent of genetic variation for transpiration efficiency in sorghum

1997 ◽  
Vol 48 (5) ◽  
pp. 649 ◽  
Author(s):  
Graeme L. Hammer ◽  
Graham D. Farquhar ◽  
Ian J. Broad
Keyword(s):  
Genetic Variation ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Selection Index ◽  
Leaf Tissue ◽  
Transpiration Efficiency ◽  
Significant Finding ◽  
Physiological Basis ◽  
Isotope Discrimination ◽  
Accepted Standard

A glasshouse study examined 49 diverse sorghum lines for variation in transpiration efficiency. Three of the 49 lines grown were Sorghum spp. native to Australia; one was the major weed Johnson grass (Sorghum halepense), and the remaining 45 lines were cultivars of Sorghum bicolor. All plants were grown under non-limiting water and nutrient conditions using a semi-automatic pot watering system designed to facilitate accurate measurement of water use. Plants were harvested 56–58 days after sowing and dry weights of plant parts were determined. Transpiration efficiency differed signficantly among cultivars. The 3 Australian native sorghums had much lower transpiration efficiency than the other 46 cultivars, which ranged from 7·7 to 6·0 g/kg. For the 46 diverse cultivars, the ratio of range in transpiration efficiency to its l.s.d. was 2·0, which was similar to that found among more adapted cultivars in a previous study. This is a significant finding as it suggests that there is likely to be little pay-off from pursuing screening of unadapted material for increased variation in transpiration efficiency. It is necessary, however, also to examine absolute levels of transpiration efficiency to determine whether increased levels have been found. The cultivar with greatest transpiration efficiency in this study (IS9710) had a value 9% greater (P < 0·05) than the accepted standard for adapted sorghum cultivars. The potential impact of such an increase in transpiration efficiency warrants continued effort to capture it. Transpiration efficiency has been related theoretically and experimentally to the degree of carbon isotope discrimination in leaf tissue in sorghum, which thus offers a relatively simple selection index. In this study, the variation in transpiration efficiency was not related simply to carbon isotope discrimination. Significant associations of transpiration efficiency with ash content and indices of photosynthetic capacity were found. However, the associations were not strong. These results suggest that a simple screening technique could not be based on any of the measures or indices analysed in this study. A better understanding of the physiological basis of the observed genetic differences in transpiration efficiency may assist in developing reliable selection indices. It was concluded that the potential value of the improvement in transpiration efficiency over the accepted standard and the degree of genetic variation found warrant further study on this subject. It was suggested that screening for genetic variation under water-limiting conditions may provide useful insights and should be pursued.

Genetic Variation in Carbon Isotope Discrimination and Its Relation to Stomatal Conductance in Pima Cotton (Gossypium barbadense)

1996 ◽  
Vol 23 (2) ◽  
pp. 127 ◽  
Author(s):  
Zhenmin Lu ◽  
Jiwei Chen ◽  
RG Percy ◽  
MR Sharifi ◽  
PW Rundel ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Stomatal Conductance ◽  
Heat Resistance ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Stable Carbon Isotope ◽  
Gossypium Barbadense ◽  
High Irradiance ◽  
Isotope Discrimination ◽  
Selection For

Stable carbon isotope discrimination (Δ) was evaluated in primitive and cultivated Gossypium barbadense L. Significant differences among cultivated Pima lines were positively associated with the degree of selection for lint yield and heat resistance. A population mean study of a cross between B368, a primitive, uncultivated G. barbadense, and Pima S-6, an advanced line, showed that Δ is probably under genetic control, and could be a suitable selection trait in breeding programs. Eleven uncultivated accessions of primitive G. barbadense of varying origins grown in one environment showed a broad range of Δ values (18.8-20.50), pointing to substantial genetic variation of Δ in the G. barbadense germplasm. A was strongly correlated with stomatal conductance (gs) in the commercial lines, a segregating F2 population of the B368 × Pima S-6 cross, and the collection of uncultivated G. barbadense. This relationship indicates that variation in gs is the main source of variation for Δ in both uncultivated and commercial G. barbadense. The positive correlation between Δ, gs and yield in the commercial Pima lines provides further evidence for selection pressures on higher gs ensuing from selection for higher yield and heat resistance. Selection for higher Δ could increase yield in crops grown in hot, high irradiance, and well-irrigated environments.

scholarly journals Leaf Age, Canopy Position, and Habitat Affect the Carbon Isotope Discrimination and Water-Use Efficiency in Three C3 Leguminous Prosopis Species from a Hyper-Arid Climate

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 402 ◽  
Author(s):  
M. Iftikhar Hussain ◽  
Ali El-Keblawy ◽  
François Mitterand Tsombou
Keyword(s):  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Leaf Age ◽  
Stable Carbon ◽  
The West ◽  
Isotope Discrimination ◽  
Canopy Position ◽  
Use Efficiency

The present study involved measurements of the stable carbon isotope composition (δ13C) and intrinsic water-use efficiency (iWUE) of three C3 leguminous Prosopis spp. (P. juliflora, P. cineraria, and P. pallida) foliage at different canopy positions (east and west) from saline (SLH) and non-saline habitats (NSH). Integrated measurements of the stable carbon isotope composition (δ13C) of plant tissue were broadly used to study iWUE, taking into consideration the effect of leaf age and canopy position on C isotope discrimination. Mature foliage of P. pallida from an SLH with a west canopy position had significantly higher δ13C (less negative) than that from NSH. On the west side, Δ13C values ranged from 17.8‰ (P. pallida) to 22.31‰ (P. juliflora) for a west canopy position, while they varied from 18.05‰ (P. pallida) to 22.4‰ (P. cineraria) on the east canopy side. Because the patterns are similar for the three Prosopis species, the difference in carbon isotope discrimination (Δ13C) between the canopy position (west and east) is relatively consistent among species and sites, ranging between 17.8 ± 4.43‰ for the young foliage in the west and 18.05 ± 4.35‰ for the east canopy position. The iWUE of P. pallida was twice that of P. cineraria. The iWUE of P. juliflora was higher from NSH than SLH. Mature leaves possessed a higher iWUE than the young leaves. We concluded that exotic P. juliflora and P. pallida have higher iWUE values than the native P. cineraria, which might be due to the rapid below-ground development of plant roots in the Arabian deserts of the United Arab Emirates (UAE). This could enable the alien species access to deeper humid soil layers or water resources.

scholarly journals An observational constraint on stomatal function in forests: evaluating coupled carbon and water vapor exchange with carbon isotopes in the Community Land Model (CLM4.5)

2016 ◽  
Vol 13 (18) ◽  
pp. 5183-5204 ◽  
Author(s):  
Brett Raczka ◽  
Henrique F. Duarte ◽  
Charles D. Koven ◽  
Daniel Ricciuto ◽  
Peter E. Thornton ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Nitrogen Limitation ◽  
Carbon Isotope Discrimination ◽  
Stable Carbon Isotope ◽  
Atmospheric Co2 ◽  
Stable Carbon ◽  
Isotope Discrimination ◽  
Community Land Model

Abstract. Land surface models are useful tools to quantify contemporary and future climate impact on terrestrial carbon cycle processes, provided they can be appropriately constrained and tested with observations. Stable carbon isotopes of CO2 offer the potential to improve model representation of the coupled carbon and water cycles because they are strongly influenced by stomatal function. Recently, a representation of stable carbon isotope discrimination was incorporated into the Community Land Model component of the Community Earth System Model. Here, we tested the model's capability to simulate whole-forest isotope discrimination in a subalpine conifer forest at Niwot Ridge, Colorado, USA. We distinguished between isotopic behavior in response to a decrease of δ13C within atmospheric CO2 (Suess effect) vs. photosynthetic discrimination (Δcanopy), by creating a site-customized atmospheric CO2 and δ13C of CO2 time series. We implemented a seasonally varying Vcmax model calibration that best matched site observations of net CO2 carbon exchange, latent heat exchange, and biomass. The model accurately simulated observed δ13C of needle and stem tissue, but underestimated the δ13C of bulk soil carbon by 1–2 ‰. The model overestimated the multiyear (2006–2012) average Δcanopy relative to prior data-based estimates by 2–4 ‰. The amplitude of the average seasonal cycle of Δcanopy (i.e., higher in spring/fall as compared to summer) was correctly modeled but only when using a revised, fully coupled An − gs (net assimilation rate, stomatal conductance) version of the model in contrast to the partially coupled An − gs version used in the default model. The model attributed most of the seasonal variation in discrimination to An, whereas interannual variation in simulated Δcanopy during the summer months was driven by stomatal response to vapor pressure deficit (VPD). The model simulated a 10 % increase in both photosynthetic discrimination and water-use efficiency (WUE) since 1850 which is counter to established relationships between discrimination and WUE. The isotope observations used here to constrain CLM suggest (1) the model overestimated stomatal conductance and (2) the default CLM approach to representing nitrogen limitation (partially coupled model) was not capable of reproducing observed trends in discrimination. These findings demonstrate that isotope observations can provide important information related to stomatal function driven by environmental stress from VPD and nitrogen limitation. Future versions of CLM that incorporate carbon isotope discrimination are likely to benefit from explicit inclusion of mesophyll conductance.

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

1992 ◽  
Vol 19 (3) ◽  
pp. 263 ◽  
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.

Stable carbon isotope discrimination in the smut fungusUstilago violacea

1986 ◽  
Vol 10 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Oscar H. Will ◽  
Larry L. Tieszen ◽  
Mark Kellen ◽  
Tamara Gerlach
Keyword(s):  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Stable Carbon Isotope ◽  
Stable Carbon ◽  
Isotope Discrimination
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