skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Why cutting respiratory CO 2 loss from crops is possible, practicable, and prudential
Abstract Plants release back to the atmosphere about half of the CO 2 they capture by photosynthesis. Decreasing the rate of crop respiration could therefore potentially increase yields, store more carbon in the soil and draw down atmospheric CO 2 . However, decreasing respiration rate has had very little research effort compared to increasing photosynthesis, the historically dominant metabolic paradigm for crop improvement. Conceptual and technical advances, particularly in protein turnover and directed enzyme evolution, have now opened ways to trim the large fraction of respiration that fuels proteome maintenance by lowering the breakdown and resynthesis rates of enzymes and other proteins. In addition to being theoretically possible and practicable, exploring the reduction of respiration is prudential, given that it (i) has barely yet been tried and (ii) could help meet the challenges of sustaining crop productivity and managing atmospheric carbon.  more » « less
Award ID(s):
1748105
PAR ID:
10461837
Author(s) / Creator(s):
; ; ; ; ; ;
Date Published:
Journal Name:
Modern Agriculture
Volume:
1
Issue:
1
ISSN:
2751-4102
Page Range / eLocation ID:
16 to 26
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; (, Environmental Research: Climate)
    Abstract Arctic amplification (AA), referring to the phenomenon of amplified warming in the Arctic compared to the warming in the rest of the globe, is generally attributed to the increasing concentrations of carbon dioxide (CO2) in the atmosphere. However, little attention has been paid to the mechanisms and quantitative variations of AA under decreasing levels of CO2, when cooling where the Arctic region is considerably larger than over the rest of the planet. Analyzing climate model experiments forced with a wide range of CO2concentrations (from 1/8× to 8×CO2, with respect to preindustrial levels), we show that AA indeed occurs under decreasing CO2concentrations, and it is stronger than AA under increasing CO2concentrations. Feedback analysis reveals that the Planck, lapse-rate, and albedo feedbacks are the main contributors to producing AAs forced by CO2increase and decrease, but the stronger lapse-rate feedback associated with decreasing CO2level gives rise to stronger AA. We further find that the increasing CO2concentrations delay the peak month of AA from November to December or January, depending on the forcing strength. In contrast, decreasing CO2levels cannot shift the peak of AA earlier than October, as a consequence of the maximum sea-ice increase in September which is independent of forcing strength. Such seasonality changes are also presented in the lapse-rate feedback, but do not appear in other feedbacks nor in the atmospheric and oceanic heat transport processeses. Our results highlight the strongly asymmetric responses of AA, as evidenced by the different changes in its intensity and seasonality, to the increasing and decreasing CO2concentrations. These findings have significant implications for understanding how carbon removal could impact the Arctic climate, ecosystems, and socio-economic activities. 
    more » « less
  2. ; ; ; ; (, Proceedings of the National Academy of Sciences)
    Carbon dioxide (CO 2 ) supersaturation in lakes and rivers worldwide is commonly attributed to terrestrial–aquatic transfers of organic and inorganic carbon (C) and subsequent, in situ aerobic respiration. Methane (CH 4 ) production and oxidation also contribute CO 2 to freshwaters, yet this remains largely unquantified. Flood pulse lakes and rivers in the tropics are hypothesized to receive large inputs of dissolved CO 2 and CH 4 from floodplains characterized by hypoxia and reducing conditions. We measured stable C isotopes of CO 2 and CH 4 , aerobic respiration, and CH 4 production and oxidation during two flood stages in Tonle Sap Lake (Cambodia) to determine whether dissolved CO 2 in this tropical flood pulse ecosystem has a methanogenic origin. Mean CO 2 supersaturation of 11,000 ± 9,000 μ atm could not be explained by aerobic respiration alone. 13 C depletion of dissolved CO 2 relative to other sources of organic and inorganic C, together with corresponding 13 C enrichment of CH 4 , suggested extensive CH 4 oxidation. A stable isotope-mixing model shows that the oxidation of 13 C depleted CH 4 to CO 2 contributes between 47 and 67% of dissolved CO 2 in Tonle Sap Lake. 13 C depletion of dissolved CO 2 was correlated to independently measured rates of CH 4 production and oxidation within the water column and underlying lake sediments. However, mass balance indicates that most of this CH 4 production and oxidation occurs elsewhere, within inundated soils and other floodplain habitats. Seasonal inundation of floodplains is a common feature of tropical freshwaters, where high reported CO 2 supersaturation and atmospheric emissions may be explained in part by coupled CH 4 production and oxidation. 
    more » « less
  3. ; ; (, New Phytologist)
    Summary Steady‐state photosyntheticCO2responses (A/Cicurves) are used to assess environmental responses of photosynthetic traits and to predict future vegetative carbon uptake through modeling. The recent development of rapidA/Cicurves (RACiRs) permits faster assessment of these traits by continuously changing [CO2] around the leaf, and may reveal additional photosynthetic properties beyond what is practical or possible with steady‐state methods.Gas exchange necessarily incorporates photosynthesis and (photo)respiration. Each process was expected to respond on different timescales due to differences in metabolite compartmentation, biochemistry and diffusive pathways. We hypothesized that metabolic lags in photorespiration relative to photosynthesis/respiration andCO2diffusional limitations can be detected by varying the rate of change in [CO2] duringRACiR assays. We tested these hypotheses through modeling and experiments at ambient and 2% oxygen.Our data show that photorespiratory delays cause offsets in predictedCO2compensation points that are dependent on the rate of change in [CO2]. Diffusional limitations may reduce the rate of change in chloroplastic [CO2], causing a reduction in apparentRACiR slopes under highCO2ramp rates.MultirateRACiRs may prove useful in assessing diffusional limitations to gas exchange and photorespiratory rates. 
    more » « less
  4. ; ; ; ; ; ; ; ; ; (, Global Change Biology)
    Abstract Microbes affect the global carbon cycle that influences climate change and are in turn influenced by environmental change. Here, we use data from a long‐term whole‐ecosystem warming experiment at a boreal peatland to answer how temperature and CO2jointly influence communities of abundant, diverse, yet poorly understood, non‐fungi microbial Eukaryotes (protists). These microbes influence ecosystem function directly through photosynthesis and respiration, and indirectly, through predation on decomposers (bacteria and fungi). Using a combination of high‐throughput fluid imaging and 18S amplicon sequencing, we report large climate‐induced, community‐wide shifts in the community functional composition of these microbes (size, shape, and metabolism) that could alter overall function in peatlands. Importantly, we demonstrate a taxonomic convergence but a functional divergence in response to warming and elevated CO2with most environmental responses being contingent on organismal size: warming effects on functional composition are reversed by elevated CO2and amplified in larger microbes but not smaller ones. These findings show how the interactive effects of warming and rising CO2levels could alter the structure and function of peatland microbial food webs—a fragile ecosystem that stores upwards of 25% of all terrestrial carbon and is increasingly threatened by human exploitation. 
    more » « less
  5. ; ; ; ; ; ; ; (, Nature Food)
    Abstract Artificial photosynthesis systems are proposed as an efficient alternative route to capture CO 2 to produce additional food for growing global demand. Here a two-step CO 2 electrolyser system was developed to produce a highly concentrated acetate stream with a 57% carbon selectivity (CO 2 to acetate), allowing its direct use for the heterotrophic cultivation of yeast, mushroom-producing fungus and a photosynthetic green alga, in the dark without inputs from biological photosynthesis. An evaluation of nine crop plants found that carbon from exogenously supplied acetate incorporates into biomass through major metabolic pathways. Coupling this approach to existing photovoltaic systems could increase solar-to-food energy conversion efficiency by about fourfold over biological photosynthesis, reducing the solar footprint required. This technology allows for a reimagination of how food can be produced in controlled environments. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email