Atmospheric CO₂ enrichment affects C3 crops both directly via increased carbon gain and improved water use efficiency and indirectly via higher temperatures and more frequent climatic extremes. Here we investigated the response of spring wheat (Triticum aestivum L. cv. Triso) to CO₂ enrichment (550 vs. 380 µmol/mol) and heat, applied as a constant +4°C increase or a typical heat wave either before or after anthesis, or as two typical heat waves before and after anthesis. We applied a climate chamber approach closely mimicking ambient conditions. CO₂ enrichment increased above-ground biomass and yield by c. 7 and 10%, but was not able to compensate for adverse heat stress effects, neither before nor after anthesis, with few exceptions only. Yield depression due to heat stress was most severe when two heat waves were applied (−19%). This adverse effect was, however, compensated by CO₂ enrichment. Applying heat stress before or after anthesis did not exert different effects on yield for both +4°C warming and heat wave application. However, +4°C depressed yield more than a heat wave at ambient CO₂, but not so at elevated CO₂. Thus, the interactive effects were complex and prediction of future wheat yield under CO₂ enrichment and climate extremes deserves more attention.

中文翻译：

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热量、小麦和 CO 2 ：时间和温度胁迫模式对生物量和产量的相关性

大气二氧化碳富集通过增加碳增加和提高用水效率直接影响 C3 作物，并通过更高的温度和更频繁的极端气候间接影响 C3 作物。在这里，我们研究了春小麦（Triticum aestivum L. cv. Triso）对 CO₂ 富集（550 对 380 µmol/mol）和热量的响应，以恒定的 +4°C 增加或之前或之后的典型热浪施加花，或作为花前和花后的两个典型的热浪。我们应用了一种气候室方法，密切模仿环境条件。CO 2 富集使地上生物量和产量增加了 c。7% 和 10%，但无法补偿不利的热应激影响，无论是在开花前还是在开花后，只有少数例外。当施加两次热浪时，热应激导致的产量下降最为严重 (-19%)。然而，这种不利影响被 CO₂ 富集抵消了。在开花前后施加热应激对 +4°C 升温和热浪施加对产量没有产生不同的影响。然而，+4°C 对环境 CO2 的抑制作用不仅仅是热浪，但在 CO2 升高的情况下则不然。因此，相互作用的影响是复杂的，在二氧化碳富集和极端气候条件下对未来小麦产量的预测值得更多关注。