Soil water status triggers CO2 fertilization effect on the growth of winter wheat (Triticum aestivum)
2020
Zheng, Yunpu | He, Chunlin | Guo, Lili | Hao, Lihua | Cheng, Dongjuan | Li, Fei | Peng, Zhengping | Xu, Ming
Understanding the key processes and potential mechanisms of crops in response to elevated atmospheric CO₂ concentration and drought may further shed lights on the impacts of climate change on the global agriculture ecosystems. This study examined the effects of elevated atmospheric CO₂ concentration on the growth of winter wheat under different soil water conditions (full irrigation, mild water stress, moderate water stress, and severe water stress) with growth chambers where the CO₂ concentration was controlled at 400 and 800 µmol mol⁻¹, respectively. We found a very strong CO₂ fertilization effect on the growth of winter wheat under full irrigation condition, whereas this CO₂ fertilization effect declined and eventually vanished with soil water stress, as evidenced by the decreased plant biomass and leaf photosynthesis of winter wheat independent of CO₂ concentration. This adverse impact of water stress on the CO₂ fertilization effect for plant growth may attribute to the changes in morphological characteristics of individual stoma and spatial distribution pattern of stomata as well as the non-structural carbohydrates of winter wheat. These results suggested that water stress may lower the CO₂ fertilization effect on plant growth through altering stomatal traits, leaf photochemical processes, and biochemical compositions of winter wheat. Therefore, many current climate models based on earlier “double-CO₂” experiment may overestimate the CO₂ fertilization effect on crops, and meanwhile underestimate the impacts of climate change on global agriculture production when the elevated atmospheric CO₂ concentration confounded with drought stress under future climate change.
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