Abstract Drought stress is one of the major stressors for plants under climate change, depressing growth through inhibition of photosynthesis and causing oxidative cell damage. It has been shown that plants can form a drought stress memory, improving their performance under recurring drought stress after they have been primed by drought before. Mechanisms underlying such a drought stress memory and possible cross-stress tolerance (improved performance to drought after plants have been stressed by other stressors) are currently unclear. We aimed to test whether previous waterlogging stress and drought stress leads to improved performance and changes in morphological, photosynthetic and anti-oxidative parameters under recurring drought. Therefore, we repeatedly subjected Alopecurus pratensis grass plants to waterlogging and drought over two years. In the third year, plants were well-watered for three weeks to recover and then subjected to drought stress for two weeks. Plants primed with drought before showed less tissue damage and higher levels of Rubisco content, anti-oxidative enzymes (POX, SOD) and chlorophyll b after the recovery and the drought period. We show for the first time a long-term drought stress memory in a grass species, lasting over several weeks. Our results indicate that drought priming enhances the activity of anti-oxidative enzymes, which is key for depressing oxidative damage and for improving tolerance to subsequent drought stress in A. pratensis.

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数周内植物应激记忆与高水平的抗氧化酶有关

摘要 干旱胁迫是气候变化下植物的主要应激源之一，通过抑制光合作用抑制生长并引起细胞氧化损伤。已经表明，植物可以形成干旱胁迫记忆，在它们之前被干旱引发后，在反复出现的干旱胁迫下提高它们的表现。这种干旱胁迫记忆和可能的交叉胁迫耐受性（在植物受到其他胁迫因素胁迫后提高抗旱性能）的机制目前尚不清楚。我们的目的是测试先前的涝渍胁迫和干旱胁迫是否会导致在反复干旱的情况下改善性能和形态、光合和抗氧化参数的变化。因此，我们在两年多的时间里反复让看麦娘草植物遭受涝渍和干旱。在第三年，植物充分浇水三周以恢复，然后经受两周的干旱胁迫。在恢复和干旱期后，干旱前引发的植物组织损伤较少，Rubisco 含量、抗氧化酶（POX、SOD）和叶绿素 b 水平较高。我们首次展示了草种的长期干旱应激记忆，持续数周。我们的结果表明，干旱启动增强了抗氧化酶的活性，这是抑制氧化损伤和提高对草履虫随后干旱胁迫耐受性的关键。恢复期和干旱期后的抗氧化酶（POX、SOD）和叶绿素b。我们首次展示了草种的长期干旱应激记忆，持续数周。我们的结果表明，干旱启动增强了抗氧化酶的活性，这是抑制氧化损伤和提高对草履虫随后干旱胁迫耐受性的关键。恢复期和干旱期后的抗氧化酶（POX、SOD）和叶绿素b。我们首次展示了草种的长期干旱应激记忆，持续数周。我们的结果表明，干旱启动增强了抗氧化酶的活性，这是抑制氧化损伤和提高对草履虫随后干旱胁迫耐受性的关键。