Onset of sheath extension and duration of lamina extension are major determinants of the response of maize lamina length to plant density

Andrieu, Bruno, Hillier, Jonathan and Birch, Colin (2006) Onset of sheath extension and duration of lamina extension are major determinants of the response of maize lamina length to plant density. Annals Of Botany, 98 5: 1005-1016. doi:10.1093/aob/mcl177


Author Andrieu, Bruno
Hillier, Jonathan
Birch, Colin
Title Onset of sheath extension and duration of lamina extension are major determinants of the response of maize lamina length to plant density
Journal name Annals Of Botany   Check publisher's open access policy
ISSN 0305-7364
1095-8290
0003-4754
Publication date 2006-11
Sub-type Article (original research)
DOI 10.1093/aob/mcl177
Volume 98
Issue 5
Start page 1005
End page 1016
Total pages 12
Place of publication Oxford, UK
Publisher Oxford University Press
Collection year 2006
Language eng
Subject CX
C1
270402 Plant Physiology
620104 Other cereals
Abstract Background and Aims Plants regulate their architecture strongly in response to density, and there is evidence that this involves changes in the duration of leaf extension. This questions the approximation, central in crop models, that development follows a fixed thermal time schedule. The aim of this research is to investigate, using maize as a model, how the kinetics of extension of grass leaves change with density, and to propose directions for inclusion of this regulation in plant models. • Methods Periodic dissection of plants allowed the establishment of the kinetics of lamina and sheath extension for two contrasting sowing densities. The temperature of the growing zone was measured with thermocouples. Two-phase (exponential plus linear) models were fitted to the data, allowing analysis of the timing of the phase changes of extension, and the extension rate of sheaths and blades during both phases. • Key Results The duration of lamina extension dictated the variation in lamina length between treatments. The lower phytomers were longer at high density, with delayed onset of sheath extension allowing more time for the lamina to extend. In the upper phytomers—which were shorter at high density—the laminae had a lower relative extension rate (RER) in the exponential phase and delayed onset of linear extension, and less time available for extension since early sheath extension was not delayed. • Conclusions The relative timing of the onset of fast extension of the lamina with that of sheath development is the main determinant of the response of lamina length to density. Evidence is presented that the contrasting behaviour of lower and upper phytomers is related to differing regulation of sheath ontogeny before and after panicle initiation. A conceptual model is proposed to explain how the observed asynchrony between lamina and sheath development is regulated.
Keyword co-ordination
emergence
leaf extension
kinetics
lamina
leaf
ligule
ontogeny
plant architecture
primordium
sheath
Zea mays
RER
LER
Co-ordination
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Agriculture and Food Sciences
 
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Created: Wed, 15 Aug 2007, 09:01:05 EST