The objective of this experiment was to investigate the responses of contrasting wheat genotypes to drought stress under ambient and elevated CO₂ environments. At anthesis, the plants from each CO₂ levels were either exposed to progressive drought or well‐watered at 95% of pot holding capacity. The results showed that for both genotypes, CO₂ elevation sensitized the plants’ response to soil drying in terms of reduction of evapotranspiration. Drought significantly reduced trans‐zeatin (tZ) concentration in leaves, salicylic acid (SA) concentration in spikes, and physiological and yield‐related traits. However, the concentration of abscisic acid (ABA) and other phytohormones was increased under drought, which coincided with an increase in the kernel abortion. Elevated CO₂ significantly increased photosynthetic rate, but had no significant effect on yield‐related traits. Genotype L₃ possessed higher concentration of leaf tz, osmotic potential, and spike SA/ABA ratio under combined drought and elevated CO₂ as compared to genotype L₂. L₃ also had higher thousand kernel weight (TKW) and grain yield in comparison to L₂. The results indicate that elevated CO₂ is not necessarily increasing yield, and biophysiochemical traits in L₃ could be used as valuable selecting criteria to obtain higher TKW and grain yield in future drier and CO₂‐enriched environment.

中文翻译：

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CO2浓度升高对花期中等干旱胁迫下两种不同小麦基因型的影响

本实验的目的是研究在环境和高CO ₂环境下，不同基因型的小麦对干旱胁迫的响应。在开花期，来自每个CO ₂水平的植物要么暴露于进行性干旱，要么处于保持盆栽能力95％的浇水状态良好。结果表明，对于两种基因型，从减少蒸散量的角度来看，CO ₂升高对植物对土壤干燥的反应敏感。干旱显著减少反式叶片中的玉米蛋白（tZ）浓度，穗中的水杨酸（SA）浓度以及生理和与产量相关的性状。然而，干旱条件下脱落酸（ABA）和其他植物激素的浓度增加，这与谷粒流产的增加相吻合。升高的CO ₂显着提高了光合速率，但对产量相关性状没有显着影响。基因型大号₃具有叶TZ，渗透势的较高浓度，和合并的干旱下尖峰SA / ABA比和高浓度CO ₂相比于基因型大号₂。与L ₂相比，L ₃还具有更高的千粒重（TKW）和谷物产量。结果表明，CO升高₂并不一定增加产量，L _3中的生物物理化学特性可以作为有价值的选择标准，以在未来更干燥和富含CO _2的环境中获得更高的TKW和谷物产量。