. 2013 Feb 1;64(6):1485–1496. doi: 10.1093/jxb/ert005

Table 5.

Relative growth rate of whole plant (RGR), relative growth rate of shoot (RGR_s), relative growth rate of root (RGR_r), allometric coefficient (K=RGR_r/RGR_s), specific leaf area (SLA), and net assimilation rate (NAR) of an old (released in 1961) and a modern (released in 1997) winter wheat cultivar exposed to elevated CO₂ and/or O₃ for 21 d in OTCs. Control (CO₂, 385±4 ppm+CFA, 4±0.02 ppb O₃); elevated CO₂ (CO₂, 714±16 ppm+CFA, 4±0.02 ppb O₃); O₃ (ambient CO₂, 385±4 ppm+elevated O₃, 72±5 ppb O₃ for 7h d^–1, 9.00–16.00h); and elevated CO₂+O₃ (elevated CO₂, 714±16 ppm+elevated O₃, 72±5 ppb 7h d^–1). Overall, elevated CO₂ significantly (P <0.001) increased RGR, RGR_s, and RGR_r but did not alter K. Exposure to O₃ significantly (P <0.05) decreased RGR, RGR_s, RGR_r, and K in wheat cultivars. Results are shown as means±1 standard error (n=10). Means with the same letter were not significantly different.

Treatment	RGR (g g^–1 d^–1)	RGR_s (g g^–1 d^–1)	RGR_r (g g^–1 d^–1)	K	SLA (cm² g^–1)	NAR (g m^–2 d^–1)
(a) Beijing 6 (1961)
Control	0.065±0.003^c	0.068±0.003^c	0.056±0.003^d	0.83±0.05^a	603±34^ab	2.34±0.13
CO₂	0.067±0.002^c	0.070±0.003^c	0.059±0.003^d	0.84±0.05^a	548±32^ab	2.54±0.13
O₃	0.062±0.002^c	0.066±0.003^c	0.050±0.003^e	0.76±0.04^b	658±30^a	2.17±0.12
CO₂+O₃	0.066±0.002^c	0.069±0.003^c	0.056±0.003^d	0.82±0.04^a	571±30^ab	2.37±0.12
(b) Zhongmai 9 (1997)
Control	0.075±0.002^b	0.077±0.003^b	0.064±0.003^b	0.84±0.04^a	592±30^ab	2.43±0.12
CO₂	0.081±0.002^a	0.084±0.003^a	0.071±0.003^a	0.84±0.05^a	527±32^ab	2.76±0.13
O₃	0.054±0.002^d	0.058±0.003^d	0.040±0.003^c	0.71±0.04^c	655±30^a	1.98±0.12
CO₂+O₃	0.076±0.002^b	0.083±0.003^a	0.065±0.003^b	0.78±0.04^b	492±30^b	2.48±0.12