CN-Wheat, a functional–structural model of carbon and nitrogen metabolism in wheat culms after anthesis. I. Model description

Abstract

Background and Aims Improving crops requires better linking of traits and metabolic processes to whole plant performance. In this paper, we present CN-Wheat, a comprehensive and mechanistic model of carbon (C) and nitrogen (N) metabolism within wheat culms after anthesis.Methods The culm is described by modules that represent the roots, photosynthetic organs and grains. Each of them includes structural, storage and mobile materials. Fluxes of C and N among modules occur through a common pool and through transpiration flow. Metabolite variations are represented by differential equations that depend on the physiological processes occurring in each module. A challenging aspect of CN-Wheat lies in the regulation of these processes by metabolite concentrations and the environment perceived by organs.Key Results CN-Wheat simulates the distribution of C and N into wheat culms in relation to photosynthesis, N uptake, metabolite turnover, root exudation and tissue death. Regulation of physiological activities by local concentrations of metabolites appears to be a valuable feature for understanding how the behaviour of the whole plant can emerge from local rules.Conclusions The originality of CN-Wheat is that it proposes an integrated view of plant functioning based on a mechanistic approach. The formalization of each process can be further refined in the future as knowledge progresses. This approach is expected to strengthen our capacity to understand plant responses to their environment and investigate plant traits adapted to changes in agronomical practices or environmental conditions. A companion paper will evaluate the model.

Macronutrient in soils and wheat from long-term agroexperiments reflects variations in residue and fertilizer inputs

“…Carbon concentration in wheat grain was affected by treatments and was greater in the SB45, SB90, NB45, NB90 than in FB and SB ( Table 1). The accumulation of N in grain has positive correlation with C in the grain 34 , and SB45, SB90, NB45, NB90 plots had greater N than in FB and SB plots. This could be the reason for greater concentrations of C in the N applied treatments than in the plots without N application.…”

Photosynthetic Acclimation to Fluctuating Irradiance in Plants

“…This equilibrium state would depend on the speed of dynamic acclimation and the degree of linearity in the response of plant traits to changes in irradiance. These dynamics have been captured in simulation models either (i) by implementing a goalseeking behavior that calculates steady-state acclimation from optimization theory (Yin et al, 2019) or (ii) by simulating protein turnover dynamically (Thornley, 1998;Kull and Kruijt, 1999;Barillot et al, 2016;Pao et al, 2019a). Experimental evidence exists that coordination across leaves may be achieved through cytokinins carried by the transpiration stream (Pons et al, 2001), as transpiration will vary according to the irradiance profile.…”

“…Experimental evidence exists that coordination across leaves may be achieved through cytokinins carried by the transpiration stream (Pons et al, 2001), as transpiration will vary according to the irradiance profile. This mechanism has been included in a recent mechanistic model of wheat incorporating plant carbon and N balances, but has not yet been validated experimentally (Barillot et al, 2016).…”

Photosynthetic Entrainment of the Circadian Clock Facilitates Plant Growth under Environmental Fluctuations: Perspectives from an Integrated Model of Phase Oscillator and Phloem Transportation

“…Numerous mathematical models on growth of various plants have been developed (e.g., Thornley and Johnson, 1990 ; Chew et al, 2014 , 2017 ; Feller et al, 2015 ; Barillot et al, 2016a , b ). Among them, two multiscale models of A. thaliana include the circadian clock sub-model and are able to quantitatively predict growth (Chew et al, 2014 , 2017 ).…”