Drought tolerance and rapid post-stress recovery are critical survival strategies for turfgrass management in areas with limited rainfall and irrigation. This study sought to determine whether elevated CO₂ could improve drought tolerance in rhizomatous Kentucky bluegrass (Poa pratensis L.) by protecting rhizomes from stress damage and promote regrowth and regeneration of daughter plants from rhizomes upon rewatering. Plants (cv. ‘Baron’) were grown at elevated CO₂ concentration (800 μl L⁻¹) or ambient CO₂ concentration (400 μl L⁻¹) for 28 d and then exposed to well-irrigated conditions (control) or drought stress by withholding irrigation for an additional 28 d, followed by rewatering in growth chambers. Elevated CO₂–treated plants had significantly higher leaf relative water content, visual quality, and membrane stability during drought compared with ambient CO₂–treated plants. Rhizome nodes of elevated CO₂–treated plants maintained significantly higher viability and lower content of abscisic acid and auxin under drought stress. In response to rewatering, plants previously exposed to drought stress under elevated CO₂ exhibited increased growth of new shoots measured as total shoot biomass and daughter-plant biomass, and an increased number of rhizomes, as well as greater canopy density compared with plants at ambient CO₂. This study suggested that elevated CO₂ concentration was able to protect rhizomes from drought damage and reactivate rhizomes for regeneration of new plants when drought was relieved by irrigation.

中文翻译：

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二氧化碳升高对肯塔基兰草根茎生长的耐旱性和干旱后恢复的影响

在降雨和灌溉有限的地区，耐旱和快速的应激后恢复是草坪管理的关键生存策略。本研究旨在确定升高的 CO ₂是否可以通过保护根茎免受胁迫损伤并促进再浇水后根茎子代植物的再生和再生来提高根状茎肯塔基早熟禾 ( Poa pratensis L.) 的耐旱性。植物（cv.'Baron'）在升高的 CO ₂浓度（800 μl L ^-1）或环境 CO ₂浓度（400 μl L ^-1) 28 天，然后暴露于良好灌溉条件（对照）或干旱胁迫下，再暂停灌溉 28 天，然后在生长室中重新浇水。高CO ₂ -处理的植物干旱期间与环境CO相比有显著较高的叶相对含水量，视觉质量和膜稳定性₂ -处理的植物。在干旱胁迫下，升高的 CO ₂处理植物的根茎节保持显着更高的活力和更低的脱落酸和生长素含量。为响应再浇水，先前在高 CO ₂下暴露于干旱胁迫的植物与环境 CO _{2 下的}植物相比，以总枝条生物量和子株生物量衡量的新枝条的生长增加，根茎数量增加，以及更大的冠层密度。该研究表明，当灌溉缓解干旱时，升高的 CO ₂浓度能够保护根茎免受干旱损害，并重新激活根茎以再生新植物。