scholarly journals Stable Carbon Isotopes in Zea mays

2018 ◽  
Author(s):  
Robert J. Twohey ◽  
Lucas M. Roberts ◽  
Anthony J. Studer
Keyword(s):  
Zea Mays ◽  
Carbon Isotopes ◽  
Water Use ◽  
Stable Carbon Isotopes ◽  
Carbon Fixation ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Climate Change Scenarios ◽  
Transpiration Efficiency ◽  
Stable Carbon

SummaryThe increasing demand for food production and predicted climate change scenarios highlight the need for improvements in crop sustainability. The efficient use of water will become increasingly important for rainfed agricultural crops even in fertile regions that have historically received ample precipitation. Improvements in water-use efficiency in Zea mays have been limited, and warrants a renewed effort aided by molecular breeding approaches. Progress has been constrained by the difficulty of measuring water-use in a field environment. The stable carbon isotope composition (δ13C) of the leaf has been proposed as an integrated signature of carbon fixation with a link to stomatal conductance. However, additional factors affecting leaf δ13C exist, and a limited number of studies have explored this trait in Z. mays. Here we present an extensive characterization of leaf δ13C in Z. mays. Significant variation in leaf δ13C exists across diverse lines of Z. mays, which we show to be heritable across several environments.Furthermore, we examine temporal and spatial variation in leaf δ13C to determine the optimum sampling time to maximize the use of leaf δ13C as a trait. Finally, our results demonstrate the relationship between transpiration and leaf δ13C in the field and the greenhouse. Decreasing transpiration and soil moisture are associated with decreasing leaf δ13C. Taken together these results outline a strategy for using leaf δ13C and reveal its usefulness as a measure of transpiration efficiency under well-watered conditions rather than a predictor of performance under drought.Significance StatementThis study identifies sources of variation in stable carbon isotopes of maize leaves and establishes the framework for connecting leaf δ13C and transpiration efficiency.

scholarly journals The Genetic Architecture of Leaf Stable Carbon Isotope Composition in Zea mays and the Effect of Transpiration Efficiency on Leaf Elemental Accumulation

2021 ◽  
Author(s):  
Crystal A Sorgini ◽  
Lucas M Roberts ◽  
Madsen Sullivan ◽  
Asaph B Cousins ◽  
Ivan Baxter ◽  
...  
Keyword(s):  
Leaf Area ◽  
Carbon Isotope ◽  
Water Use ◽  
Specific Leaf Area ◽  
Genetic Architecture ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Carbon Isotope Composition ◽  
Transpiration Efficiency ◽  
Stable Carbon

Abstract With increased demand on freshwater resources for agriculture, it is imperative that more water-use efficient crops are developed. Leaf stable carbon isotope composition, δ13C, is a proxy for transpiration efficiency and a possible tool for breeders, but the underlying mechanisms effecting δ13C in C4 plants are not known. It has been suggested that differences in specific leaf area, which potentially reflects variation in internal CO2 diffusion, can impact leaf δ13C. Furthermore, although it is known that water movement is important for elemental uptake, it is not clear how manipulation of transpiration for increased water-use efficiency may impact nutrient accumulation. Here we characterize the genetic architecture of leaf δ13C and test its relationship to specific leaf area and the ionome in five populations of maize. Five significant QTL for leaf δ13C were identified, including novel QTL as well as some that were identified previously in maize kernels. One of the QTL regions contains an Erecta-like gene, the ortholog of which has been shown to regulate transpiration efficiency and leaf δ13C in Arabidopsis. QTL for δ13C were located in the same general chromosome region, but slightly shifted, when comparing data from two different years. Our data does not support a relationship between δ13C and specific leaf area, and of the 19 elements analyzed, only a weak correlation between molybdenum and δ13C was detected. Together these data add to the genetic understanding of leaf δ13C in maize and suggest that improvements to plant water use may be possible without significantly influencing elemental homeostasis.

scholarly journals The Genetic Architecture of Leaf Stable Carbon Isotope Composition in Zea mays and the Effect of Transpiration Efficiency on Elemental Accumulation

2020 ◽  
Author(s):  
Crystal A. Sorgini ◽  
Lucas M. Roberts ◽  
Asaph B. Cousins ◽  
Ivan Baxter ◽  
Anthony J. Studer
Keyword(s):  
Leaf Area ◽  
Carbon Isotope ◽  
Water Use ◽  
Specific Leaf Area ◽  
Genetic Architecture ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Carbon Isotope Composition ◽  
Transpiration Efficiency ◽  
Stable Carbon

ABSTRACTWith increased demand on freshwater resources for agriculture, it is imperative that more water-use efficient crops are developed. Leaf stable carbon isotope composition, δ13C, is a proxy for transpiration efficiency and a possible tool for breeders, but the underlying mechanisms effecting δ13C in C4 plants are not known. It has been suggested that differences in specific leaf area, which potentially reflects variation in internal CO2 diffusion, can impact leaf δ13C. However, at this point the relationship has not been tested in maize. Furthermore, although it is known that water movement is important for elemental uptake, it is not clear how manipulation of transpiration for increased water-use efficiency may impact nutrient accumulation. Here we characterize the underlying genetic architecture of leaf δ13C and test its relationship to specific leaf area and the ionome in four biparental populations of maize. Five significant QTL for leaf δ13C were identified, including both novel QTL as well as some that were identified previously in maize kernels. One of the QTL regions contains an Erecta-like gene, the ortholog of which has been shown to regulate transpiration efficiency and leaf δ13C in Arabidopsis. Our data does not support a relationship between δ13C and specific leaf area, and of the 19 elements analyzed, only a weak correlation between molybdenum and δ13C was detected. Together these data begin to build a genetic understanding of leaf δ13C in maize and suggest the potential to improve plant water use without significantly influencing elemental homeostasis.Article SummaryQuantitative genetics approaches were used to investigate the genetic architecture of leaf stable carbon isotope discrimination (δ13C) in maize. Developing a better understanding of leaf δ13C could facilitate its use in breeding for reduced transpirational water loss. Several genomic regions were identified that contribute to the variation observed in leaf δ13C. Furthermore, contrary to what has been observed in other species, leaf δ13C was not correlated with specific leaf area. Finally, a leaf ionomic analysis indicates that a reduction in transpiration, and thus mass flow, would not result in a decrease in nutrient accumulation.

Stable carbon isotope analysis of faecal and blood samples of sheep in relation to the diet

2003 ◽  
Vol 2003 ◽  
pp. 159-159
Author(s):  
A. Balcaen ◽  
E. Claeys ◽  
V. Fievez ◽  
P. Boeckx ◽  
O. van Cleemput ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotope ◽  
Carbon Fixation ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Isotope Analysis ◽  
Calvin Cycle ◽  
Isotopic Fractionation ◽  
Woody Species ◽  
Stable Carbon

Stable isotopes have been extraordinarily helpful in understanding animal migration, diet, food webs and nutrient flow (Hilderbrand et al., 1996), based on the property that C3 and C4 plants possess distinctly different 13C/12C ratios (δ13C value) due to isotopic fractionation during photosynthetic carbon fixation (Smith & Epstein, 1971). Most woody species and temperate graminoids assimilate carbon via the Calvin cycle (C3), which discriminates stronger against the heavier isotope (13C) than Hatch-Slack (C4) species (tropical and subtropical graminoids and some shrubs). C3 and C4 plant species have mean δ13C values of -27 ‰ and -13 ‰ respectively (O’Leary, 1981). DeNiro & Epstein (1978) were one of the first to show that the isotopic composition of the whole animal body is similar to that of its diet. Other authors have also found relationships between the isotopic composition of animal tissues and the diet (González-Martin et al., 1999; Jones et al., 1979). The aim of this study was to investigate stable carbon isotope composition in sheep fed diets consisting of either C3 or C3+C4 plants.

Vertical stratification of Neotropical leaf-nosed bats (Chiroptera: Phyllostomidae) revealed by stable carbon isotopes

2011 ◽  
Vol 27 (03) ◽  
pp. 211-222 ◽  
Author(s):  
Katja Rex ◽  
Robert Michener ◽  
Thomas H. Kunz ◽  
Christian C. Voigt
Keyword(s):  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Species Interactions ◽  
Rain Forest ◽  
Stable Carbon Isotopes ◽  
Stable Carbon Isotope ◽  
The Body ◽  
Vertical Stratification ◽  
Forest Site ◽  
Stable Carbon

Abstract:Tropical rain forests harbour the most diverse plant and animal assemblages known to science, but our understanding of assemblage structure and species interactions is limited. Bats, as the only flying mammals, have the potential to exploit resources from all strata in forest communities. Thus, fruit-eating phyllostomid bats often have been categorized into canopy-, subcanopy- and understorey-foraging species, based largely upon the height at which they were most frequently captured. Here we challenge this classification and use stable carbon isotopes to assess foraging height of bat species at an Amazonian rain-forest site in Ecuador and at a Caribbean lowland rain-forest site in Costa Rica for comparison with data from mist-net captures. The proportion of the heavy stable carbon isotope13C in relation to the lighter12C isotope increases in plants from ground level to the canopy (0.12‰ m−1–0.18‰ m−1), and these differences in stable carbon isotope signatures are reflected in the body tissue of phytophagous bats. We used the stable carbon isotope ratio (δ13C) of wing tissue to estimate the foraging heights of 54 phyllostomid species in two Neotropical bat assemblages. Based on stable isotope data, phyllostomid species exploit food resources at all vertical strata of the forest. Capture height was not a reliable predictor of foraging height and suggests that bats most likely use lower strata to commute between foraging sites to avoid predators. Vertical stratification is likely to be a key factor promoting niche partitioning, thus promoting high local species richness in many tropical animal assemblages.

scholarly journals Degradation changes stable carbon isotope depth profiles in palsa peatlands

2014 ◽  
Vol 11 (1) ◽  
pp. 1383-1412 ◽  
Author(s):  
J. P. Krüger ◽  
J. Leifeld ◽  
C. Alewell
Keyword(s):  
Carbon Isotope ◽  
Carbon Isotopes ◽  
Stable Carbon Isotopes ◽  
Stable Carbon Isotope ◽  
Stable Carbon ◽  
Δ13c Values ◽  
Depth Profiles ◽  
Degradation Rates ◽  
Aerobic Decomposition ◽  
Permafrost Thawing

Abstract. Palsa peatlands are a significant carbon pool in the global carbon cycle and are projected to change by global warming due to accelerated permafrost thaw. Our aim was to use stable carbon isotopes as indicators of palsa degradation. Depth profiles of stable carbon isotopes generally reflect organic matter dynamics in soils with an increase of δ13C values during aerobic decomposition and stable or decreasing δ13C values with depth during anaerobic decomposition. Stable carbon isotope depth profiles of undisturbed and degraded sites of hummocks as well as hollows at three palsa peatlands in northern Sweden were used to investigate the degradation processes. The depth patterns of stable isotopes clearly differ between intact and degraded hummocks at all sites. Erosion and cryoturbation at the degraded sites significantly changes the stable carbon isotope depth profiles. At the intact hummocks the uplifting of peat material by permafrost is indicated by a turning in the δ13C depth trend and this assessment is supported by a change in the C / N ratios. For hollows isotope patterns were less clear, but some hollows and degraded hollows in the palsa peatlands show differences in their stable carbon isotope depth profiles indicating enhanced degradation rates. We conclude that the degradation of palsa peatlands by accelerated permafrost thawing could be identified with stable carbon isotope depth profiles. At intact hummocks δ13C depth patterns display the uplifting of peat material by a change in peat decomposition processes.

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