RT Journal Article
SR Electronic
T1 Circadian rhythms have significant effects on leaf-to-canopy gas exchange under field conditions
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 054593
DO 10.1101/054593
A1 Víctor Resco de Dios
A1 Arthur Gessler
A1 Juan Pedro Ferrio
A1 Josu G Alday
A1 Michael Bahn
A1 Jorge del Castillo
A1 Sébastien Devidal
A1 Sonia García-Muñoz
A1 Zachary Kayler
A1 Damien Landais
A1 Paula Martín
A1 Alexandru Milcu
A1 Clément Piel
A1 Karin Pirhofer-Walzl
A1 Olivier Ravel
A1 Serajis Salekin
A1 David T Tissue
A1 Mark G Tjoelker
A1 Jordi Voltas
A1 Jacques Roy
YR 2016
UL http://biorxiv.org/content/early/2016/05/21/054593.abstract
AB Molecular clocks drive oscillations in leaf photosynthesis, stomatal conductance and other cell and leaf level processes over ~24 h under controlled laboratory conditions. The influence of such circadian regulation over whole canopy fluxes remains uncertain and diurnal CO2 and H2O vapor flux dynamics in the field are currently interpreted as resulting almost exclusively from direct physiological responses to variations in light, temperature and other environmental factors. We tested whether circadian regulation would affect plant and canopy gas exchange at the CNRS Ecotron. Canopy and leaf level fluxes were constantly monitored under field-like environmental conditions, and also under constant environmental conditions (no variation in temperature, radiation or other environmental cues). Here we show first direct experimental evidence at canopy scales of circadian gas exchange regulation: 20-79% of the daily variation range in CO2 and H2O fluxes occurred under circadian entrainment in canopies of an annual herb (bean) and of a perennial shrub (cotton). We also observed that considering circadian regulation improved performance in commonly used stomatal conductance models. Overall, our results show that overlooked circadian controls affect diurnal patterns of CO2 and H2O fluxes in entire canopies and in field-like conditions, although this process is currently unaccounted for in models.