scholarly journals Effects of environmental salinity on carbon isotope discrimination and stomatal conductance in Spartina grasses

2006 ◽  
Vol 313 ◽  
pp. 305-310 ◽  
Author(s):  
Maricle Brian R. ◽  
Lee Raymond W.
Keyword(s):  
Stomatal Conductance ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Isotope Discrimination ◽  
Environmental Salinity

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.

GAS EXCHANGE, GROWTH, YIELD AND BEVERAGE QUALITY OF COFFEA ARABICA CULTIVARS GRAFTED ON TO C. CANEPHORA AND C. CONGENSIS

2001 ◽  
Vol 37 (2) ◽  
pp. 241-252 ◽  
Author(s):  
J. I. FAHL ◽  
M. L. C. CARELLI ◽  
H. C. MENEZES ◽  
P. B. GALLO ◽  
P. C. O. TRIVELIN
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Carbon Isotope ◽  
Coffea Arabica ◽  
Carbon Isotope Discrimination ◽  
Growth Yield ◽  
Carbon Gain ◽  
Dry Period ◽  
Isotope Discrimination

Gas exchange, leaf carbon isotope discrimination, growth, yield and beverage quality were evaluated for two Coffea arabica cultivars (Catuai and Mundo Novo), grafted on to C. canephora and C. congensis progenies growing in open fields. During the years 1994 to 1997, grafting resulted in an average increase in bean yield of 151 and 89% for Catuai and Mundo Novo respectively. As analysed by sensory analyses and by the ratio between the mono-isomers and di-isomers of caffeoylquinic acid, beverage quality of the C. arabica was not altered by grafting. Shoot growth was significantly greater in grafted plants, showing an increase of 52% in total leaf area compared with the non-grafted plants. Under conditions of water excess in the soil there was little difference in the transpiration and stomatal conductance rates between the grafted and non-grafted plants, but the net photosynthesis was higher in grafted plants. With an accentuated water deficit in the soil in the dry period, the grafted plants showed significantly higher transpiration and stomatal conductance rates than the non-grafted plants, and similar values to those of C. canephora. Carbon isotope discrimination was greater in the grafted plants, suggesting greater root hydraulic conductance. The results suggest that the better performance of the grafted plants during the dry period was due to the greater capacity of the root system of C. canephora to provide water to the shoot thereby maintaining greater gas exchange in the leaves and consequently a greater carbon gain.

Effect of Growth Form, Salinity, Nutrient and Sulfide on Photosynthesis, Carbon Isotope Discrimination and Growth of Red Mangrove (Rhizophora mangle L.)

1992 ◽  
Vol 19 (5) ◽  
pp. 509 ◽  
Author(s):  
GH Lin ◽  
LDSL Sternberg
Keyword(s):  
Stomatal Conductance ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
High Salinity ◽  
Co2 Assimilation ◽  
Transpiration Efficiency ◽  
Growth Forms ◽  
Growth Responses ◽  
Isotope Discrimination ◽  
Red Mangrove

The red mangrove (Rhizophora mangle L.), a dominant mangrove species in Florida, frequently occurs in two distinct growth forms, scrub and tall trees. These two growth forms show significant differences in physiology in the field, with lower CO2 assimilation rate, stomatal conductance, and carbon isotope discrimination or higher transpiration efficiency for the scrub form. To elucidate the possible factors responsible for these physiological differences, we studied the physiological and growth responses of scrub and tall red mangrove seedlings grown hydroponically in the greenhouse under 12 different growth conditions combining three salinities (100, 250, 500 mM NaCl), two nutrient levels (10, 100% strength of full nutrient solution), and two sulfide concentrations (0, 2.0 mM Na2S). The two growth forms showed similar physiological and growth responses to these treatments, suggesting no genetic control of physiological and growth differences between the growth forms of this species. High salinity, low nutrient level, and high sulfide concentration all significantly decreased CO2 assimilation, stomatal conductance, and plant growth, but only salinity significantly decreased intercellular CO2 concentration and leaf carbon isotope discrimination, suggesting that the lower carbon isotope discrimination, or higher transpiration efficiency, observed for scrub mangroves in the field is caused only by high salinity during the dry season. Hypersalinity thus seems to be one of the stressful environmental conditions common to all scrub red mangrove forests studied in southern Florida.

PAPER PRESENTED AT INTERNATIONAL WORKSHOP ON INCREASING WHEAT YIELD POTENTIAL, CIMMYT, OBREGON, MEXICO, 20–24 MARCH 2006 An economic assessment of the use of physiological selection for stomatal aperture-related traits in the CIMMYT wheat breeding programme

2007 ◽  
Vol 145 (3) ◽  
pp. 187-194 ◽  
Author(s):  
J. P. BRENNAN ◽  
A. G. CONDON ◽  
M. VAN GINKEL ◽  
M. P. REYNOLDS
Keyword(s):  
Stomatal Conductance ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
International Workshop ◽  
Wheat Yield ◽  
Indirect Selection ◽  
Economic Benefits ◽  
Yield Potential ◽  
Breeding Programme ◽  
Isotope Discrimination

Physiological research has shown that measurements on small plots of stomatal conductance, canopy temperature depression (CTD) or carbon isotope discrimination may be useful for screening breeding populations for yield potential, prior to the execution of expensive replicated yield trials. Such indirect selection criteria may be very effective as lower cost alternatives for estimating genetic gain for complex characteristics such as yield that are relatively expensive to measure accurately in the field. In the present paper, economic analysis is undertaken of the results of trials conducted at the International Maize and Wheat Improvement Center (CIMMYT) over three seasons to determine the value of the physiological traits being assessed. The results indicate that the economic value of incorporating these measurements into CIMMYT's breeding programme is potentially important. CTD and stomatal conductance are relatively cheap to measure and could be used to discard lines prior to extensive yield testing, whereas carbon isotope discrimination is relatively expensive and would not be economic for this purpose. The analysis indicates that the incorporation of physiological measurements is likely to provide important economic benefits to the programme. Indications are that other breeding programmes with similar breeding goals and comparable costing structures might also consider using such indirect selection traits.

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.

Carbon Isotope Discrimination and Photosynthetic Gas Exchange in Coffee Hedgerows During Canopy Development

1994 ◽  
Vol 21 (2) ◽  
pp. 207 ◽  
Author(s):  
MV Gutierrez ◽  
FC Meinzer
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Carbon Isotope ◽  
Carbon Isotope Discrimination ◽  
Area Index ◽  
Canopy Development ◽  
Isotope Discrimination ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Sun Leaves

In evergreen species, leaf carbon isotope discrimination (Δ) integrates phenological rhythms in gas exchange as well as seasonal changes in environmental conditions. However, few reports on long term variations in Δ of woody plants are available. We measured Δ, gas exchange, nitrogen content, and photosynthetic nitrogen-use efficiency (PNUE) in coffee hedgerows at different stages of canopy development encompassing a range of leaf area index (LAI) from 0.7 to 7.5. Assimilation was highest in sun leaves, but stomatal conductance was highest in shaded leaves. This resulted in a high correlation between assimilation and stomatal conductance in sun, but not in shaded leaves. Δ was about 20 lower in sun than in shaded leaves, and varied by 2.30 among leaves at different positions along two-year- old branches. These differences in Δ were the result of changes in carbon isotope composition that occurred in mature, fully expanded leaves as they became shaded during subsequent canopy growth. Results from a mass balance model based on leaf gas exchange characteristics and measured foliar Δ values suggested that about 50% of the carbon originally fixed during leaf development in the sun may have subsequently been turned over in the shade. Δ of sun leaves from the upper canopy decreased by about 20 with increasing LAI, indicating that intrinsic water-use efficiency (WUE) of this canopy layer increased during canopy development. In contrast, instantaneous WUE, estimated as assimilation divided by canopy transpiration obtained from sap flow measurements, seemed to decrease with increasing LAI. PNUE of upper canopy sun leaves decreased with increasing LAI, suggesting a physiological compromise between WUE and PNUE mediated by stomatal conductance, which also decreased with increasing LAI. A strong negative correlation obtained between leaf Δ and N content was consistent with a trade-off between intrinsic water- and N-use efficiency.

Genomic analysis of carbon isotope discrimination, photosynthesis rate, stomatal conductance, and grain yield in wheat (Triticum aestivum L.) under water-stressed conditions

2012 ◽  
Vol 63 (6) ◽  
pp. 513 ◽  
Author(s):  
Shahram Mohammady ◽  
Roghayeh Aminian ◽  
Sadolla Hoshmand ◽  
Mahmood Khodombashi
Keyword(s):  
Stomatal Conductance ◽  
Grain Yield ◽  
Carbon Isotope ◽  
Chinese Spring ◽  
Carbon Isotope Discrimination ◽  
Wheat Variety ◽  
Photosynthesis Rate ◽  
Research Station ◽  
Substitution Lines ◽  
Isotope Discrimination

Chromosomal substitution lines of wheat variety Timstein (Tim) into the genetic background of variety Chinese Spring (CS) were used to evaluate the chromosomal location of genes controlling carbon isotope discrimination (Δ), photosynthesis rate (PR), stomatal conductance (SC), and grain yield. The experiment was carried out in the field at Shahrekord University Research Station. Considerable variation was observed among the substitution lines and between the parents for all traits. Chinese Spring had smaller values for the characters under study than Timstein. Significant correlations were found for grain yield with PR (r = 0.556) and Δ (r = 0.619). The substitution line CS (Tim2B) was significantly different from CS for Δ (P < 0.01). The substitution of homeologous group 3 chromosomes produced significant differences from the recipient variety for PR. Substitution lines CS (Tim3A), CS (Tim3B), CS (Tim4B), and CS (Tim1D) were significantly different from CS for SC. Genomic comparisons indicated that genome B had higher values of all four characters compared with the A and D genomes. Homeologous effects of genomes were documented for Δ and PR only and not for SC and grain yield.

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