Bigger is not always better: reducing leaf area helps stay-green sorghum use soil water more slowly

George-Jaeggli, Barbara, Mortlock, Miranda Yolanda and Borrell, Andrew Kenneth (2017) Bigger is not always better: reducing leaf area helps stay-green sorghum use soil water more slowly. Environmental and Experimental Botany, 138 119-129. doi:10.1016/j.envexpbot.2017.03.002

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Author George-Jaeggli, Barbara
Mortlock, Miranda Yolanda
Borrell, Andrew Kenneth
Title Bigger is not always better: reducing leaf area helps stay-green sorghum use soil water more slowly
Journal name Environmental and Experimental Botany   Check publisher's open access policy
ISSN 0098-8472
Publication date 2017-06-01
Year available 2017
Sub-type Article (original research)
DOI 10.1016/j.envexpbot.2017.03.002
Open Access Status File (Author Post-print)
Volume 138
Start page 119
End page 129
Total pages 11
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Subject 1105 Ecology, Evolution, Behavior and Systematics
1102 Agronomy and Crop Science
1110 Plant Science
Abstract Stay-green, a trait that confers delayed leaf senescence and improved grain yield under post-anthesis drought, has been associated with smaller canopies at flowering and increased water uptake during the post-flowering period. It has been shown that the main stay-green quantitative trait loci reduce leaf area via reduced tiller number and smaller leaves. To show that these canopy characteristics are directly linked to water savings, we grew near-isogenic lines with and without stay-green introgressions in large lysimeter pots and measured their weekly pre-anthesis water use and main-stem and tiller leaf area. Paradoxically, age-related senescence of lower leaves in stay-green lines was accelerated before flowering, contributing to their smaller leaf area at flowering. This process of reducing leaf area by shedding old leaves lower in the canopy, has not previously been described for the stay-green introgressions. We found that tiller leaf area rather than transpiration efficiency, or transpiration per leaf area, was the main driver of weekly transpiration and the reduced pre-flowering water use in stay-green lines. In soils with good water-holding capacity, any water savings during the pre-anthesis period increases water availability during the post-anthesis period, therefore allowing plants to retain photosynthetic capacity for longer by “staying green” during grain filling.
Keyword Drought
Canopy development
Sorghum (Sorghum bicolor)
Night-time transpiration
Q-Index Code C1
Q-Index Status Provisional Code
Grant ID DAQ00085
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Agriculture and Food Sciences
Queensland Alliance for Agriculture and Food Innovation
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Created: Wed, 05 Apr 2017, 13:06:20 EST by Dr Miranda Y. Mortlock on behalf of School of Agriculture and Food Sciences