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Plant function and evolutionary biology
RESEARCH ARTICLE (Open Access)

Inferring vascular architecture of the wheat spikelet based on resource allocation in the branched headt (bht-A1) near isogenic lines

Gizaw M. Wolde https://orcid.org/0000-0003-2278-817X A B D and Thorsten Schnurbusch orcid.org/0000-0002-5267-0677 A C D
+ Author Affiliations
- Author Affiliations

A Independent HEISENBERG-Research Group Plant Architecture, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, OT Gatersleben, D-06466 Seeland, Germany.

B Present address: Department of Plant Sciences, University of California, Davis, CA 95616, USA.

C Faculty of Natural Sciences III, Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, 06120 Halle, Germany.

D Corresponding authors. Emails: wolde@ipk-gatersleben.de; thor@ipk-gatersleben.de

Functional Plant Biology 46(11) 1023-1035 https://doi.org/10.1071/FP19041
Submitted: 12 June 2018  Accepted: 21 June 2019   Published: 23 September 2019

Journal Compilation © CSIRO 2019 Open Access CC BY-NC-ND

Abstract

Substantial genetic and physiological efforts were made to understand the causal factors of floral abortion and grain filling problem in wheat. However, the vascular architecture during wheat spikelet development is surprisingly under-researched. We used the branched headt near-isogenic lines, FL-bht-A1-NILs, to visualise the dynamics of spikelet fertility and dry matter accumulation in spikelets sharing the same rachis node (henceforth Primary Spikelet, PSt, and Secondary Spikelet, SSt). The experiment was conducted after grouping FL-bht-A1-NILs into two groups, where tillers were consistently removed from one group. Our results show differential spikelet fertility and dry matter accumulation between the PSt and SSt, but also showed a concomitant improvement after de-tillering. This suggests a tight regulation of assimilate supply and dry matter accumulation in wheat spikelets. Since PSt and SSt share the same rachis node, the main vascular bundle in the rachis/rachilla is expected to bifurcate to connect each spikelet/floret to the vascular system. We postulate that the vascular structure in the wheat spikelet might even follow Murray’s law, where the wide conduits assigned at the base of the spikelet feed the narrower conduits of the distal florets. We discuss our results based on the two modalities of the vascular network systems in plants.

Additional keywords: assimilate partitioning, bifurcation, modeling, aorta, primary spikelet, secondary spikelet, spikelet fertility, Triticum durum, vascular bundle.


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