Department of Soil & Water Sciences, Institute of Environmental Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
Department of Vegetable and Field Crop Research, Agricultural Research Organization, Gilat Research Center, Gilat, Israel.
Plant Cell Environ. 2022 Dec;45(12):3445-3461. doi: 10.1111/pce.14430. Epub 2022 Sep 27.
The combination of a future rise in atmospheric carbon dioxide concentration ([CO ]) and drought will significantly impact wheat production and quality. Genotype phenology is likely to play an essential role in such an effect. Yet, its response to elevated [CO ] and drought has not been studied before. Here we conducted a temperature-controlled glasshouse [CO ] enrichment experiment in which two wheat cultivars with differing maturity timings and life cycle lengths were grown under ambient (aCO approximately 400 μmol mol ) and elevated (eCO approximately 550 μmol mol ) [CO ]. The two cultivars, bred under dry and warm Mediterranean conditions, were well-watered or exposed to drought at 40% pot holding capacity. We aimed to explore water × [CO ] × genotype interaction in terms of phenology, physiology, and agronomic trait response. Our results show that eCO had a significant effect on plants grown under drought. eCO boosted the booting stage of the late-maturing genotype (cv. Ruta), thereby prolonging its booting-to-anthesis period by approximately 3 days (p < 0.05) while unaffecting the phenological timing of the early-maturing genotype (cv. Zahir). The prolonged period resulted in a much higher carbon assimilation rate, particularly during pre-anthesis (+87% for Ruta vs. +22% for Zahir under eCO ). Surprisingly, there was no eCO effect on transpiration rate and grain protein content in both cultivars and under both water conditions. The higher photosynthesis (and transpiration efficiency) of Ruta was not translated into higher aboveground biomass or grain yield, whereas both cultivars showed a similar increase of approximately 20% in these two traits at eCO under drought. Overall, Zahir, the cultivar that responded the least to eCO had a more efficient source-to-sink balance with a lower sink limitation than Ruta. The complex water × [CO ] × genotype interaction found in this study implies that future projections should account for multifactor interactive effects in modeling wheat response to future climate.
未来大气二氧化碳浓度（[CO ]）上升和干旱的结合将对小麦生产和质量产生重大影响。基因型物候可能在这种影响中发挥重要作用。然而，它对升高的[CO ]和干旱的响应尚未得到研究。在这里，我们进行了一个温度控制的温室[CO ]富集实验，其中两个具有不同成熟时间和生命周期长度的小麦品种在大气（aCO 约 400 μmol/mol）和升高的（eCO 约 550 μmol/mol）[CO ]下生长。这两个品种是在干燥温暖的地中海条件下培育的，充分浇水或在 40%的盆持水量下暴露于干旱。我们旨在探索水 × [CO ] × 基因型互作对物候、生理和农艺性状响应的影响。我们的结果表明，eCO 对干旱条件下生长的植物有显著影响。eCO 促进了晚熟基因型（cv. Ruta）的拔节期，从而将其拔节到抽穗期延长了约 3 天（p < 0.05），而不影响早熟基因型（cv. Zahir）的物候时间。延长的时间导致更高的碳同化率，特别是在抽穗前（eCO 下 Ruta 比 Zahir 高 87%）。令人惊讶的是，在两种水分条件下，eCO 对两个品种的蒸腾速率和籽粒蛋白质含量都没有影响。Ruta 更高的光合作用（和蒸腾效率）并没有转化为更高的地上生物量或籽粒产量，而在干旱条件下，eCO 下两个品种的这两个性状都增加了约 20%。总体而言，对 eCO 反应最小的品种 Zahir 具有更高的源库平衡效率，对源的限制低于 Ruta。本研究中发现的复杂水 × [CO ] × 基因型互作表明，未来的预测应该考虑到多因素交互效应对建模小麦对未来气候的响应。
