The water use dynamics of canola cultivars grown under elevated CO2 are linked to their leaf area development

Shihab Uddin; Shahnaj Parvin; Markus Löw; Glenn J Fitzgerald; Sabine Tausz-Posch; Roger Armstrong; Michael Tausz

doi:10.1016/j.jplph.2018.08.001

The water use dynamics of canola cultivars grown under elevated CO₂ are linked to their leaf area development

J Plant Physiol. 2018 Oct:229:164-169. doi: 10.1016/j.jplph.2018.08.001. Epub 2018 Aug 8.

Authors

Shihab Uddin¹, Shahnaj Parvin², Markus Löw³, Glenn J Fitzgerald⁴, Sabine Tausz-Posch⁵, Roger Armstrong⁶, Michael Tausz⁷

Affiliations

¹ Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia; Department of Agronomy, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh. Electronic address: shihab.uddin@unimelb.edu.au.
² Department of Agronomy, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh; School of Ecosystem and Forest Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia.
³ Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia.
⁴ Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia; Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, VIC 3401, Australia.
⁵ Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia; School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
⁶ Department of Economic Development, Jobs, Transport and Resources, Private Bag 260, Horsham, VIC 3401, Australia; Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Bundoora, VIC 3086, Australia.
⁷ School of Ecosystem and Forest Sciences, The University of Melbourne, 4 Water Street, Creswick, VIC 3363, Australia; Birmingham Institute of Forest Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.

PMID: 30103086
DOI: 10.1016/j.jplph.2018.08.001

Abstract

The 'CO₂ fertilisation effect' is often predicted to be greater under drier than wetter conditions, mainly due to hypothesised early season water savings under elevated [CO₂] (e[CO₂]). However, water savings largely depend on the balance between CO₂-induced improvement of leaf-level water use efficiency and CO₂-stimulation of transpiring leaf area. The dynamics of water use during the growing season can therefore vary depending on leaf area development. Two canola (Brassica napus L.) cultivars of contrasting growth and vigour (vigorous hybrid cv. Hyola 50 and non-hybrid cv. Thumper) were grown under ambient [CO₂] (a[CO₂], ∼400 μmol mol^-1) or e[CO₂] (∼700 μmol mol^-1) with two water treatments (well-watered and mild drought) in a glasshouse to investigate the interdependence of leaf area development and water use. Dynamics of water use during the growing season varied depending on [CO₂] and cultivars. Early stimulation of leaf growth under e[CO₂], which also depended on cultivar, overcompensated for the effect of increased leaf-level water use efficiency, so that weekly water use was greater and water depletion from soil greater under e[CO₂] than a[CO₂]. This result shows that the balance between leaf area and water use efficiency stimulation by e[CO₂] can tip towards early depletion of available soil water, so that e[CO₂] does not lead to water savings, and the 'CO₂ fertilisation effect' is not greater under drier conditions.

Keywords: Climate change; Drought; Elevated [CO(2)]; Leaf area; Soil water depletion; Water use dynamics.

MeSH terms

Brassica napus / growth & development
Brassica napus / metabolism*
Carbon Dioxide / metabolism*
Climate Change
Droughts
Plant Leaves / growth & development
Plant Leaves / metabolism*
Water / metabolism*

Substances

Water
Carbon Dioxide