Journal article
Carbon sink strength of nodules but not other organs modulates photosynthesis of faba bean (Vicia faba) grown under elevated [CO2] and different water supply
The New Phytologist, Vol.227(1), pp.132-145
07/2020
PMID: 32129887
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Abstract
Photosynthetic stimulation by elevated [CO2] (e[CO2]) may be limited by the capacity of sink organs to use photosynthates. In many legumes, N2-fixing symbionts in root nodules provide an additional sink, so that legumes may be better able to profit from e[CO2]. However, drought not only constrains photosynthesis but also the size and activity of sinks, and little is known about the interaction of e[CO2] and drought on carbon sink strength of nodules and other organs.
To compare carbon sink strength, faba bean was grown under ambient (400 ppm) or elevated (700 ppm) atmospheric [CO2] and subjected to well-watered or drought treatments, and then exposed to 13C pulse-labelling using custom-built chambers to track the fate of new photosynthates.
Drought decreased 13C uptake and nodule sink strength, and this effect was even greater under e[CO2], and was associated with an accumulation of amino acids in nodules. This resulted in decreased N2 fixation, and increased accumulation of new photosynthates (13C/sugars) in leaves, which in turn can feed back on photosynthesis.
Our study suggests that nodule C sink activity is key to avoid sink limitation in legumes under e[CO2], and legumes may only be able to achieve greater C gain if nodule activity is maintained.
Details
- Title
- Carbon sink strength of nodules but not other organs modulates photosynthesis of faba bean (Vicia faba) grown under elevated [CO2] and different water supply
- Creators
- Shahnaj Parvin - Southern Cross UniversityShihab Uddin - University of MelbourneSabine Tausz‐Posch - Central Queensland UniversityRoger Armstrong - La Trobe UniversityMichael Tausz - Central Queensland University
- Publication Details
- The New Phytologist, Vol.227(1), pp.132-145
- Publisher
- Wiley-Blackwell Publishing Ltd.
- Number of pages
- 14
- Grant note
- Australian Commonwealth Department of Agriculture and Water Resources (FtRG1193982) Australian Research Council Grain Research and Development Corporation, (DAV00137) Photosynthetic stimulation by elevated [CO2] (e[CO2]) may be limited by the capacity of sink organs to use photosynthates. In many legumes, N2-fixing symbionts in root nodules provide an additional sink, so that legumes may be better able to profit from e[CO2]. However, drought not only constrains photosynthesis but also the size and activity of sinks, and little is known about the interaction of e[CO2] and drought on carbon sink strength of nodules and other organs. To compare carbon sink strength, faba bean was grown under ambient (400 ppm) or elevated (700 ppm) atmospheric [CO2] and subjected to well-watered or drought treatments, and then exposed to 13C pulse-labelling using custom-built chambers to track the fate of new photosynthates. Drought decreased 13C uptake and nodule sink strength, and this effect was even greater under e[CO2], and was associated with an accumulation of amino acids in nodules. This resulted in decreased N2 fixation, and increased accumulation of new photosynthates (13C/sugars) in leaves, which in turn can feed back on photosynthesis. Our study suggests that nodule C sink activity is key to avoid sink limitation in legumes under e[CO2], and legumes may only be able to achieve greater C gain if nodule activity is maintained. SP received a Melbourne International Research Scholarship and a Postgraduate Writing-Up Grant supported by The Albert Shimmins Fund.
- Identifiers
- 991012925496702368
- Copyright
- © 2020 The Authors. New Phytologist © 2020 New Phytologist Trust
- Academic Unit
- Faculty of Science and Engineering; School of Environment, Science and Engineering; Science; Southern Cross Plant Science
- Language
- English
- Resource Type
- Journal article