Short-term responses of leaf growth rate to water deficit scale up to whole-plant and crop levels: an integrated modelling approach in maize.
Physiological and genetic studies of leaf growth often focus on short-term responses, leaving a gap to whole-plant models that predict biomass accumulation, transpiration and yield at crop scale. To bridge this gap, we developed a model that combines an existing model of leaf 6 expansion in response to short-term environmental variations with a model coordinating the development of all leaves of a plant. The latter was based on: (1) rates of leaf initiation, appearance and end of elongation measured in field experiments; and (2) the hypothesis of an independence of the growth between leaves. The resulting whole-plant leaf model was integrated into the generic crop model APSIM which provided dynamic feedback of environmental conditions to the leaf model and allowed simulation of crop growth at canopy level. The model was tested in 12 field situations with contrasting temperature, evaporative demand and soil water status. In observed and simulated data, high evaporative demand reduced leaf area at the whole-plant level, and short water deficits affected only leaves developing during the stress, either visible or still hidden in the whorl. The model adequately simulated whole-plant profiles of leaf area with a single set of parameters that applied to the same hybrid in all experiments. It was also suitable to predict biomass accumulation and yield of a similar hybrid grown in different conditions. This model extends to field conditions existing knowledge of the environmental controls of leaf elongation, and can be used to simulate how their genetic controls flow through to yield.
Chenu
Karine
K
INRA, UMR 759 LEPSE, 2 place Viala, 34060 Montpellier Cedex 01, France.
Chapman
Scott C
SC
Hammer
Graeme L
GL
McLean
Greg
G
Salah
Halim Ben Haj
HB
Tardieu
François
F
D018556:Crops, Agricultural / Q000378:metabolism*; D008954:Models, Biological; D018515:Plant Leaves / Q000254:growth & development* / Q000378:metabolism*; D018526:Plant Transpiration / Q000502:physiology; D012987:Soil; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism*
D012987:Soil; D014867:Water