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Abstract：
Maize is one of the most economically important cereal crops worldwide. Salinity coupled with waterlogging is a major challenge for successful crop production. Understanding the underlying mechanisms and impacts of individual and combined salinity and waterlogging stress on the morpho-physio-biochemical and molecular responses and oxidative metabolism of maize during stress and recovery periods is essential. The present study was carried out to assess the response of four hybrid maize cultivars viz. DK-6142, FH-1231, FH-949, and MALKA-2016 under individual and combined salinity and waterlogging conditions. The treatments comprised the control (no stress), NaCl (salinity with 10 dSm-1), WL (waterlogged conditions with 3 cm flooding), and NaCl + WL (combined salinity and waterlogging stress). The data regarding morpho-physiological attributes were collected at 22 days after sowing (DAS; stress phase) and 30 DAS (recovery phase). The results revealed that both stresses, either individually or in combination, substantially reduced the root-shoot length, root-shoot fresh and dry weights, leaf width, and the number of leaves per plant as well as the leaf chlorophyll (Chl) and carotenoids contents; however, the inhibitory effects were more severe in combined stresses than for individual stress factors in many cultivars. Both individual and combined stress conditions enhanced hydrogen peroxide (H2O2) accumulation, whereas the antioxidant enzyme activities, i.e., superoxide dismutase (SOD), peroxidase (POD) catalase (CAT), and ascorbate peroxidase (APX), remained higher under stress conditions compared to the control. The expression levels of antioxidant genes (CAT and POD) were also upregulated under stress conditions. All of the cultivars recovered better from individual stresses than combined stress conditions; however, the hybrid DK-6142 performed better than the other maize hybrids under stress conditions and showed faster recovery.
摘要：
玉米是世界上最重要的经济粮食作物之一。盐度加上水涝是成功作物生产的主要挑战。了解在胁迫和恢复期，单个和联合盐度和淹水胁迫对玉米形态生理生化和分子响应以及氧化代谢的潜在机制和影响至关重要。本研究旨在评估四个杂交玉米品种的反应。DK-6142，FH-1231，FH-949和MALKA-2016在单独和组合盐度和内涝条件下。治疗包括对照（无压力），NaCl（盐度为10dSm-1），WL(3cm洪水淹没条件),和NaCl+WL(盐度和淹水胁迫组合)。在播种后22天(DAS;应激阶段)和30天(恢复阶段)收集关于形态生理属性的数据。结果表明，两种应力，无论是单独还是组合，大大减少了根茎的长度，根茎鲜重和干重，叶片宽度,和每株植物的叶片数量以及叶片叶绿素（Chl）和类胡萝卜素含量；但是，在许多品种中，联合胁迫的抑制作用比单个胁迫因子的抑制作用更严重。个体和组合胁迫条件都增强了过氧化氢（H2O2）的积累，而抗氧化酶的活性，即，超氧化物歧化酶（SOD），过氧化物酶（POD）过氧化氢酶（CAT），和抗坏血酸过氧化物酶（APX），与对照相比，在胁迫条件下保持较高。在胁迫条件下，抗氧化基因（CAT和POD）的表达水平也上调。所有品种从单个胁迫中恢复的比组合胁迫条件更好；然而，杂种DK-6142在胁迫条件下的表现优于其他玉米杂种，并且恢复更快。
