Table 1.
Sowing date and mean daily solar radiation (Rs) at canopy tops in the chambers; for four CO2 concentrations and two dry seasons (DS) and two wet season (WS).
Table 2.
Summary of mean climate variables inside the CO2 chambers observed during the crop cycle in WS 2013 on top of the crop canopy.
Table 3.
Daily measured evapotranspiration (ET), calculated potential evapotranspiration (ETo), and derived crop coefficient (KC = ET ETo-1) for 27 days in the growth chambers having different CO2 concentration.
Table 4.
Observations and ANOVA for measured days from sowing to flowering, days from sowing to grain maturity and aboveground dry weight (agdw) for four CO2 concentration treatments and four seasons.
Fig 1.
A: Response of final above ground dry weight (agdw) to atmospheric CO2 concentration for two dry seasons (DS) and two wet seasons (WS), differing in solar radiation levels. B: Dynamics of potential ET (ETo, Table 3) and crop ET in 2013 WS. C: Dynamics of crop coefficient Kc (ET/ETo) in 2013 WS. D: Response of Kc to atmospheric CO2 concentration during three periods of crop development. Error bars represent SEM for multiple measurements on different plants within a chamber.
Fig 2.
Response to atmospheric CO2 concentration of number of leaves appeared on main culm (A), number of tillers produced per hill (B) and leaf area index (C) at flowering stage.
Error bars indicate SEM of means of biological replications within a chamber and not replications of treatment.
Table 5.
CO2 concentration effect on cumulative ET as directly measured during 27 days of observation (for daily values see Table 3) and for the whole crop cycle (extrapolated using the model in S1 Fig).
Fig 3.
A: Response to atmospheric CO2 concentration of final total agdw (TDW) and cumulative crop water use. Water use was calculated from daily calculations of Kc as shown in S1 Fig. B: Response of leaf-level transpiration efficiency (TE) and crop-level water use efficiency (WUE).