
TY  - JOUR
A1  - Ziska, Lewis H. 
A1  - Bunce, James A. 
T1  - Effect of elevated carbon dioxide concentration at night on the growth and gas exchange of selected C<emph tye="8">4</emph> species
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 1999
VL  - 26
IS  - 1
SP  - 71
EP  - 77
KW  - Climate change, carbon dioxide, C4 plants, Amaranthus retroflexus, respiration.
UR  - https://doi.org/10.1071/PP98136 
N2  - Biomass of certain C4 species is increased when plants are grown at elevated CO2 concentrations. Experiments using four C4 species (Amaranthus retroflexus L., Amaranthus hypochondriacus L., Sorghum bicolor (L.) Moench and Zea mays L.) exposed both day and night from sowing to carbon dioxide concentrations of 370 (ambient) or 700 &#181;mol mol-1 (elevated) or to 370 &#181;mol mol-1 during the day and 700 &#181;mol mol-1 at night, determined whether any biomass increase at elevated CO2 concentrations was related to a reduction in the night-time rate of CO2 efflux at high night-time CO2 concentrations. Of the four species tested, only A. retroflexus significantly increased both CO2 assimilation (+13%) and plant biomass (+21%) at continuous elevated relative to continuous ambient concentrations of CO2. This increase was not associated with improvement in leaf water potential during dark or light periods. In contrast, high CO2 only during the night significantly reduced plant biomass compared to the 24 h ambient CO2 treatment for both A. retroflexus and Z. mays. This indicates that the observed increase in biomass at elevated CO2 for A. retroflexus was not caused by a reduction of carbon loss at night (i.e. increased carbon conservation), but rather a direct stimulation of daytime CO2 assimilation, independent of any improvement in leaf water potential. 
ER  -

