Changes of (A) plant height, (B) ear height, (C) stem diameter, (D) leaf area and (E) aboveground biomass (means ± SD) (n = 3) in six treatments (C₅₅₀W_+15%, C₅₅₀W₀, C₄₅₀W_+15%, C₄₅₀W₀, C₃₉₀W_+15% and C₃₉₀W₀) in silking stage of maize under effects of elevated [CO₂] and irrigation.

<p>Different lower cases letters indicated significant difference (P<0.05).</p

<i>P</i>_n of experimental value comparing with <i>P</i>_n of model predicted value.

<p>The 1∶1 line indicates <i>P</i>_n of experimental value equals to the predicted value.</p

Change on ear characteristics of maize under effects of elevated [CO₂] and irrigation.

<p>The data are means ± SD (n = 3).</p><p>Different lower cases letters (a,b,c,d,e) indicated significant difference (<i>P</i><0.05).</p

Dynamic curves of (A) net photosynthetic rate (<i>P</i>_n), (B) transpiration rate (<i>T</i>_r), (C) water use efficiency (<i>WUE</i>), (D) stomatal conductance (<i>G</i>_s) and (E) intercellular CO₂ concentration (<i>C</i>_i) (means ± SD) (n = 3) in six treatments (C₅₅₀W_+15%, C₅₅₀W₀, C₄₅₀W_+15%, C₄₅₀W₀, C₃₉₀W_+15% and C₃₉₀W₀) in silking stage of maize under effects of elevated [CO₂] and irrigation.

<p>Dynamic curves of (A) net photosynthetic rate (<i>P</i>_n), (B) transpiration rate (<i>T</i>_r), (C) water use efficiency (<i>WUE</i>), (D) stomatal conductance (<i>G</i>_s) and (E) intercellular CO₂ concentration (<i>C</i>_i) (means ± SD) (n = 3) in six treatments (C₅₅₀W_+15%, C₅₅₀W₀, C₄₅₀W_+15%, C₄₅₀W₀, C₃₉₀W_+15% and C₃₉₀W₀) in silking stage of maize under effects of elevated [CO₂] and irrigation.</p

Monthly average precipitation during 1981–2010 years in the growing season of Maize in study area.

<p>Gray bars indicate the regional monthly averages precipitation from 1981 to 2010, and black bars indicate increased 15% precipitation based on gray bars.</p

Parameters of irradiance-response curves of maize under effects of elevated [CO₂] and different irrigation.

<p>Abbreviations are: <i>P</i>_nmax - maximum net photosynthetic rate, <i>LSP</i> - light saturation point, <i>LCP</i> - light compensation point, <i>φ</i>_c - quantum efficiency of the light compensation point, <i>R</i>_d - dark respiration.</p

The relative soil moisture (means ± SD) (n = 3) in six treatments (C₅₅₀W_+15%, C₅₅₀W₀, C₄₅₀W_+15%, C₄₅₀W₀, C₃₉₀W_+15% and C₃₉₀W₀) in silking stage of maize under effects of elevated [CO₂] and irrigation.

<p>The relative soil moisture (means ± SD) (n = 3) in six treatments (C₅₅₀W_+15%, C₅₅₀W₀, C₄₅₀W_+15%, C₄₅₀W₀, C₃₉₀W_+15% and C₃₉₀W₀) in silking stage of maize under effects of elevated [CO₂] and irrigation.</p

View of Open Top Chambers on 21 July 2013 at Liaoning province, China.

<p>View of Open Top Chambers on 21 July 2013 at Liaoning province, China.</p

The two-way analysis of variances on growth and yield of maize between different elevated [CO₂] and irrigation treatment.

<p>* and ** indicated <i>P</i><0.05 and <i>P</i><0.01, respectively.</p

Treatments performed in OTCs.

<p>Treatments performed in OTCs.</p