scholarly journals Variations in δ13C of different plant organs: implications for post-photosynthetic fractionation

2017 ◽  
Author(s):  
Yonge Zhang ◽  
Xinxiao Yu ◽  
Lihua Chen ◽  
Guodong Jia
Keyword(s):  
Carbon Isotope ◽  
Organic Materials ◽  
Isotope Composition ◽  
Water Status ◽  
Time Lag ◽  
Water Soluble ◽  
Plant Organs ◽  
Multiple Processes ◽  
Below Ground ◽  
Photosynthetic Fractionation

ABSTRACTCompared to photosynthetic fractionation, the mechanism of post-photosynthetic carbon isotope fractionation is not well understood. The aim of this study was to investigate post-photosynthetic fractionation in both above and below ground tissues and to evaluate potential hypotheses explaining differences in carbon isotope composition (δ13C) among different plant organs, which can provide valuable insights into plant physiology. The results revealed that there is no significant day-night difference in δ13C of twig phloem water soluble organic materials (WSOM), which could be explained by the unrestricted exchange of triose-phosphates between the chloroplast and cytoplasm and a time lag for carbohydrate exportation. Further, we found that δ13C of twig phloem WSOM is more sensitive to plant water status than leaf WSOM. Analysis of δ13C in different plant organs showed that the greatest 13C enrichment was recorded in stem phloem. Divergences in δ13C of phloem WSOM among different plant organs were not likely to be explained by respiratory fractionation or time lag and were ascribed to transport of carbohydrates across organ boundaries and metabolic processes. Our study demonstrated that post-photosynthesis fractionation could not be ascribed to a single, unifying hypotheses; instead, it is the result of multiple processes.Highlightδ13C of twig phloem water soluble organic materials varied no clear diel pattern. In the leaf-twig-stem-root sequence, the greatest 13C enrichment was recorded in stem phloem.

scholarly journals High time-resolved measurement of stable carbon isotope composition in water-soluble organic aerosols: method optimization and a case study during winter haze in East China

2018 ◽  
Author(s):  
Wenqi Zhang ◽  
Yan-Lin Zhang ◽  
Fang Cao ◽  
Yankun Xiang ◽  
Yuanyuan Zhang ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Isotope ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Organic Aerosols ◽  
Carbon Isotope Composition ◽  
Water Soluble ◽  
High Time ◽  
Stable Carbon ◽  
Air Mass

Abstract. Water soluble organic carbon (WSOC) is a significant fraction of organic carbon (OC) in atmospheric aerosols. WSOC is of great interest due to its significant effects on atmospheric chemistry, the Earth’s climate and human health. Stable carbon isotope (δ13C) can be used to track the potential sources and investigate atmospheric processes of organic aerosols. In this study, a method of simultaneously measuring the mass concentration and δ13C values of WSOC from aerosol samples is established by coupling the Gas Bench II preparation device with isotopic ratio mass spectrometry. The precision and accuracy of isotope determination is better than 0.17 ‰ and 0.5 ‰, respectively, for samples containing carbon larger than 5 μg. This method is then applied for the high time-resolution aerosol samples during a severe wintertime haze period in Nanjing, East China. WSOC varies between 3–32 μg m−3, whereas δ13C-WSOC ranges from −26.24 ‰ to −23.35 ‰. Three different episodes (e.g., namely the Episode 1, the Episode 2, the Episode 3) are identified in the sampling period, showing a different tendency of δ13C-WSOC with the accumulation process of WSOC aerosols. The increases in both the WSOC mass concentrations and the δ13C-WSOC values in the Episode 1 indicate that WSOC is subject to a substantial photochemical aging during the air mass transport. In the Episode 2, the decline of the δ13C-WSOC is accompanied by the increase in the WSOC mass concentrations, which is associated with regional-transported biomass burning emissions. In the Episode 3, heavier isotope (13C) is exclusively enriched in total carbon (TC) compares to WSOC aerosols. This suggests that water-insoluble carbon may contain 13C-enriched components such as dust carbonate which is supported by the enhanced Ca2+ concentrations and air mass trajectories analysis. The present study provides a novel method to determine stable carbon isotope composition of WSOC and it offers a great potential to better understand the source emission, the atmospheric aging and the secondary production of water soluble organic aerosols.

scholarly journals Carbon Isotope Composition and the NDVI as Phenotyping Approaches for Drought Adaptation in Durum Wheat: Beyond Trait Selection

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1679
Author(s):  
Rut Sanchez-Bragado ◽  
Maria Newcomb ◽  
Fadia Chairi ◽  
Giuseppe Emanuele Condorelli ◽  
Richard W. Ward ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Carbon Isotope ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Isotope Composition ◽  
Water Status ◽  
Carbon Isotope Composition ◽  
Phenotypic Traits ◽  
Drought Adaptation ◽  
Leaf Level

High-throughput phenotyping platforms provide valuable opportunities to investigate biomass and drought-adaptive traits. We explored the capacity of traits associated with drought adaptation such as aerial measurements of the Normalized Difference Vegetation Index (NDVI) and carbon isotope composition (δ13C) determined at the leaf level to predict genetic variation in biomass. A panel of 248 elite durum wheat accessions was grown at the Maricopa Phenotyping platform (US) under well-watered conditions until anthesis, and then irrigation was stopped and plot biomass was harvested about three weeks later. Globally, the δ13C values increased from the first to the second sampling date, in keeping with the imposition of progressive water stress. Additionally, δ13C was negatively correlated with final biomass, and the correlation increased at the second sampling, suggesting that accessions with lower water-use efficiency maintained better water status and, thus, performed better. Flowering time affected NDVI predictions of biomass, revealing the importance of developmental stage when measuring the NDVI and the effect that phenology has on its accuracy when monitoring genotypic adaptation to specific environments. The results indicate that in addition to choosing the optimal phenotypic traits, the time at which they are assessed, and avoiding a wide genotypic range in phenology is crucial.

Biochemical and transcriptomic analysis of maize diversity to elucidate drivers of leaf carbon isotope composition

2018 ◽  
Vol 45 (5) ◽  
pp. 489 ◽  
Author(s):  
Allison R. Kolbe ◽  
Anthony J. Studer ◽  
Asaph B. Cousins
Keyword(s):  
Carbon Isotope ◽  
Isotope Composition ◽  
Carbon Isotope Composition ◽  
Rubisco Activity ◽  
Bisphosphate Carboxylase ◽  
Co2 Diffusion ◽  
Or Gene ◽  
Photosynthetic Fractionation ◽  
Future Work

Carbon isotope discrimination is used to study CO2 diffusion, substrate availability for photosynthesis, and leaf biochemistry, but the intraspecific drivers of leaf carbon isotope composition (δ13C) in C4 species are not well understood. In this study, the role of photosynthetic enzymes and post-photosynthetic fractionation on δ13C (‰) was explored across diverse maize inbred lines. A significant 1.3‰ difference in δ13C was observed between lines but δ13C did not correlate with in vitro leaf carbonic anhydrase (CA), phosphoenolpyruvate carboxylase (PEPC), or ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity. RNA-sequencing was used to identify potential differences in post-photosynthetic metabolism that would influence δ13C; however, no correlations were identified that would indicate significant differences in post-photosynthetic fractionation between lines. Variation in δ13C has been observed between C4 subtypes, but differential expression of NADP-ME and PEP-CK pathways within these lines did not correlate with δ13C. However, co-expression network analysis provided novel evidence for isoforms of C4 enzymes and putative transporters. Together, these data indicate that diversity in maize δ13C cannot be fully explained by variation in CA, PEPC, or Rubisco activity or gene expression. The findings further emphasise the need for future work exploring the influence of stomatal sensitivity and mesophyll conductance on δ13C in maize.

scholarly journals Carbon isotope composition of sugars in grapevine, an integrated indicator of vineyard water status

2002 ◽  
Vol 53 (369) ◽  
pp. 757-763 ◽  
Author(s):  
Jean‐Pierre Gaudillère ◽  
Cornelius Van Leeuwen ◽  
Nathalie Ollat
Keyword(s):  
Carbon Isotope ◽  
Isotope Composition ◽  
Water Status ◽  
Carbon Isotope Composition

scholarly journals High time-resolved measurement of stable carbon isotope composition in water-soluble organic aerosols: method optimization and a case study during winter haze in eastern China

2019 ◽  
Vol 19 (17) ◽  
pp. 11071-11087 ◽  
Author(s):  
Wenqi Zhang ◽  
Yan-Lin Zhang ◽  
Fang Cao ◽  
Yankun Xiang ◽  
Yuanyuan Zhang ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Isotope Composition ◽  
Eastern China ◽  
Stable Carbon Isotope ◽  
Organic Aerosols ◽  
Carbon Isotope Composition ◽  
Water Soluble ◽  
Total Carbon ◽  
Stable Carbon ◽  
Air Mass

Abstract. Water-soluble organic carbon (WSOC) is a significant fraction of organic carbon (OC) in atmospheric aerosols. WSOC is of great interest due to its significant effects on atmospheric chemistry, the Earth's climate and human health. The stable carbon isotope (δ13C) can be used to track the potential sources and investigate atmospheric processes of organic aerosols. However, the previous methods measuring the δ13C values of WSOC in ambient aerosols require a large amount of carbon content, are time-consuming and require labor-intensive preprocessing. In this study, a method of simultaneously measuring the mass concentration and the δ13C values of WSOC from aerosol samples is established by coupling the GasBench II preparation device with isotopic ratio mass spectrometry. The precision and accuracy of isotope determination is better than 0.17 ‰ and 0.5 ‰, respectively, for samples containing WSOC amounts larger than 5 µg. This method is then applied for the aerosol samples collected every 3 h during a severe wintertime haze period in Nanjing, eastern China. The WSOC values vary between 3 and 32 µg m−3, whereas δ13C−WSOC ranges from −26.24 ‰ to −23.35 ‰. Three different episodes (Episode 1, Episode 2 and Episode 3) are identified in the sampling period, showing a different tendency of δ13C−WSOC with the accumulation process of WSOC aerosols. The increases in both the WSOC mass concentrations and the δ13C−WSOC values in Episode 1 indicate that WSOC is subject to a substantial photochemical aging during the air mass transport. In Episode 2, the decline of the δ13C−WSOC is accompanied by the increase in the WSOC mass concentrations, which is associated with regional-transported biomass burning emissions. In Episode 3, heavier isotope (13C) is exclusively enriched in total carbon (TC) in comparison to WSOC aerosols. This suggests that the non-WSOC fraction in total carbon may contain 13C-enriched components such as dust carbonate, which is supported by the enhanced Ca2+ concentrations and air mass trajectory analysis. The present study provides a novel method to determine the stable carbon isotope composition of WSOC, and it offers a great potential to better understand the source emission, the atmospheric aging and the secondary production of water-soluble organic aerosols.

scholarly journals Timing of water limitations affects source to sink differences in δ13C composition in apple

2021 ◽  
Author(s):  
Lee Kalcsits ◽  
Nadia Valverdi ◽  
Michelle Reid
Keyword(s):  
Carbon Isotope ◽  
Environmental Conditions ◽  
Deficit Irrigation ◽  
Isotope Composition ◽  
Water Status ◽  
Carbon Isotope Composition ◽  
Physiological Level ◽  
Irrigation Treatments ◽  
Source And Sink ◽  
Irrigation Practices

Deficit irrigation is used to reduce vegetative vigor, increase fruit quality, and conserve water resources. However, physiological responses to deficit irrigation can vary depending on soil and environmental conditions. Although physiological measurements are often made at single points in time, responses are often longer lasting and a measurement that integrates responses over time would have greater value in assessing the effectiveness of deficit irrigation practices. Carbon isotope composition has long been used as a proxy measurement for water-use efficiency, stomatal conductance, and carbon dioxide exchange with the atmosphere and is heavily influenced by water status. Potentially, fruit, leaves, or other tissues could be used as samples for carbon isotope measurements. However, it is not well known how irrigation practices can influence both source and sink tissue carbon isotope composition in perennial systems. Here, we used two experiments to determine how irrigation timing affects both source and sink δ13C at the end of the season. Irrigation limitations were initiated after bloom for either the whole season or for early, middle, or late season and compared to a well-watered control. For both experiments, leaves were poor indicators of irrigation deficit treatments that were applied during the season. There were no significant differences in leaf δ13C between deficit treatments and the control for both experiments. However, all sink tissues including roots and stems in experiment one for both years and for fruits in experiment two for both years were significantly more enriched compared to the well-watered control. Environmental conditions during the season also appeared to influence the magnitude of difference inδ13Cbetween deficit irrigation treatments and the control. These results indicate that the use of sink tissues are more sensitive for measuring signals associated with in-season water deficits. Carbon isotope composition can be an effective proxy to measure efficacy of irrigation treatments at the physiological level.

The influence of hydrodynamics on the carbon isotope composition of inorganically precipitated calcite

2021 ◽  
Vol 565 ◽  
pp. 116932
Author(s):  
Hao Yan ◽  
Wolfgang Dreybrodt ◽  
Huiming Bao ◽  
Yongbo Peng ◽  
Yu Wei ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Isotope Composition ◽  
Carbon Isotope Composition
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