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

George-Jaeggli, Barbara and 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 . pp. 119-129. ISSN 0098-8472

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Article Link(s): http://dx.doi.org/10.1016/j.envexpbot.2017.03.002

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.

Item Type:Article
Business groups:Crop and Food Science
Keywords:Drought Canopy development Senescence Sorghum Stay-green Transpiration
Subjects:Agriculture > Agriculture (General) > Agricultural meteorology. Crops and climate
Agriculture > Agriculture (General) > Methods and systems of culture. Cropping systems
Agriculture > Agriculture (General) > Soil conservation and protection
Agriculture > Agriculture (General) > Conservation of natural resources
Plant culture > Field crops > Sorghum
Deposited On:28 Mar 2017 03:47
Last Modified:28 Mar 2017 03:47

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