The projected increase in atmospheric CO₂ concentration (CO₂) is expected to enhance rice yield, while the temperature increase lowers it. However, how air temperature increase modifies this effect of CO₂ fertilization is still unclear, particularly across different ambient temperatures. To investigate this phenomenon, a temperature-free air CO₂ enrichment experiment in paddy field was conducted in 2013 and 2014. An japonica rice (Oryza sativa L.) Wuyunjing 23 was exposed to two levels of CO₂ (ambient and elevated by 200 μmol mol⁻¹ during daytime) in combination with two temperature regimes (ambient and elevated by ca. 1 ℃ during daytime). Elevated CO₂ significantly increased grain yield in both seasons, but temperature impacts on the magnitude of CO₂ responses differed between two seasons: a significant CO₂ × temperature interaction was detected in 2013 (mean air temperature 26.6 ℃), with 24 % increase in grain yield under ambient temperature vs 8 % under elevated temperature; while in 2014 (mean air temperature 23.6 ℃), a similar CO₂-induced increase under ambient (+12 %) and elevated temperature (+16 %) was detected. Plant height significantly increased upon CO₂ elevation in 2014 at various growth stages but not in 2013. The effects of CO₂ × temperature interaction on grain yield were primarily attributed to variations in panicle (or tiller) numbers, with negligible effects on other yield components. The aboveground biomass patterns mirrored those of grain yield in the responses to CO₂, temperature and their interaction, while less effect of CO₂ or temperature treatment was found on harvest index. The results demonstrate that interactions between CO₂ and temperature on rice are dependent on growth season temperature: high daytime temperature stress during the early growth period of rice can interfere with tillering formation and lead to less yield gain from CO₂ enrichment.

_{预计大气中CO 2}浓度(CO ₂ )的增加将提高水稻产量，而气温升高则会降低水稻产量。然而，气温升高如何改变CO ₂施肥的效果仍不清楚，特别是在不同的环境温度下。为了研究这一现象，我们于2013年和2014年在稻田进行了无温空气CO _{2富集实验。将粳稻（} Oryza sativa L.）乌云粳23暴露于两种水平的CO ₂（环境浓度和升高200 μmol） mol ^-1白天）与两种温度状态（环境温度和白天升高约 1 ℃）相结合。CO ₂升高显着增加了两个季节的谷物产量，但温度对 CO ₂响应幅度的影响在两个季节之间有所不同：2013 年检测到显着的 CO ₂ ×温度交互作用（平均气温 26.6 ℃），产量增加了 24%。常温下的籽粒产量 vs 高温下的 8%；而在2014年（平均气温23.6℃），在环境温度（+12%）和高温（+16%）下检测到类似的CO _{2引起的增加。}2014年不同生长阶段CO ₂升高后株高显着增加，但2013年则没有。CO ₂ ×温度相互作用对籽粒产量的影响主要归因于穗数（或分蘖数）的变化，对其他产量组成部分的影响可以忽略不计。地上生物量模式反映了谷物产量对CO ₂、温度及其相互作用的响应，而CO ₂或温度处理对收获指数的影响较小。结果表明，水稻上CO ₂和温度之间的相互作用取决于生长季节温度：水稻生长早期的白天高温胁迫会干扰分蘖形成，并导致CO ₂富集带来的产量增益减少。