TY - JOUR
T1 - Nonlinear dynamics of the CAM circadian rhythm in response to environmental forcing
AU - Hartzell, Samantha
AU - Bartlett, Mark S.
AU - Virgin, Lawrence
AU - Porporato, Amilcare
N1 - Funding Information:
This work was partially funded through the Agriculture and Food Research Initiative of the USDA National Institute of Food and Agriculture ( 2011-67003-30222 ); the National Science Foundation through Grants CBET-1033467 , EAR-1331846 , FESD-1338694 , and EAR-1316258 ; and by the U.S. Department of Energy (DOE) through the office of Biological and Environmental Research (BER) Terrestrial Carbon Processes Program ( DE-SC0006967 ). We thank Prof. Paolo Inglese of the Universitá degli Studi di Palermo for his useful suggestions and comments.
Publisher Copyright:
© 2014 Elsevier Ltd.
PY - 2015/3/7
Y1 - 2015/3/7
N2 - Crassulacean acid metabolism (CAM) photosynthesis functions as an endogenous circadian rhythm coupled to external environmental forcings of energy and water availability. This paper explores the nonlinear dynamics of a new CAM photosynthesis model (Bartlett et al., 2014) and investigates the responses of CAM plant carbon assimilation to different combinations of environmental conditions. The CAM model (Bartlett et al., 2014) consists of a Calvin cycle typical of C3 plants coupled to an oscillator of the type employed in the Van der Pol and FitzHugh-Nagumo systems. This coupled system is a function of environmental variables including leaf temperature, leaf moisture potential, and irradiance. Here, we explore the qualitative response of the system and the expected carbon assimilation under constant and periodically forced environmental conditions. The model results show how the diurnal evolution of these variables entrains the CAM cycle with prevailing environmental conditions. While constant environmental conditions generate either steady-state or periodically oscillating responses in malic acid uptake and release, forcing the CAM system with periodic daily fluctuations in light exposure and leaf temperature results in quasi-periodicity and possible chaos for certain ranges of these variables. This analysis is a first step in quantifying changes in CAM plant productivity with variables such as the mean temperature, daily temperature range, irradiance, and leaf moisture potential. Results may also be used to inform model parametrization based on the observed fluctuating regime.
AB - Crassulacean acid metabolism (CAM) photosynthesis functions as an endogenous circadian rhythm coupled to external environmental forcings of energy and water availability. This paper explores the nonlinear dynamics of a new CAM photosynthesis model (Bartlett et al., 2014) and investigates the responses of CAM plant carbon assimilation to different combinations of environmental conditions. The CAM model (Bartlett et al., 2014) consists of a Calvin cycle typical of C3 plants coupled to an oscillator of the type employed in the Van der Pol and FitzHugh-Nagumo systems. This coupled system is a function of environmental variables including leaf temperature, leaf moisture potential, and irradiance. Here, we explore the qualitative response of the system and the expected carbon assimilation under constant and periodically forced environmental conditions. The model results show how the diurnal evolution of these variables entrains the CAM cycle with prevailing environmental conditions. While constant environmental conditions generate either steady-state or periodically oscillating responses in malic acid uptake and release, forcing the CAM system with periodic daily fluctuations in light exposure and leaf temperature results in quasi-periodicity and possible chaos for certain ranges of these variables. This analysis is a first step in quantifying changes in CAM plant productivity with variables such as the mean temperature, daily temperature range, irradiance, and leaf moisture potential. Results may also be used to inform model parametrization based on the observed fluctuating regime.
KW - Bifurcation
KW - Chaos
KW - Circadian rhythm oscillator
KW - Crassulacean acid metabolism (CAM) photosynthesis
KW - Quasi-periodicity
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U2 - 10.1016/j.jtbi.2014.12.010
DO - 10.1016/j.jtbi.2014.12.010
M3 - Article
C2 - 25542971
AN - SCOPUS:84921636342
VL - 368
SP - 83
EP - 94
JO - Journal of Theoretical Biology
JF - Journal of Theoretical Biology
SN - 0022-5193
ER -