| 生育后期干旱胁迫对玉米碳氮分配及生理特征的影响 |
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| 引用本文：孙焕烜，尚宏越，郭银银，张 佩，董志强，李亚君.生育后期干旱胁迫对玉米碳氮分配及生理特征的影响[J].西北农业学报,2023,(5):706~713 |
| DOI:10.7606/j.issn.1004-1389.2023.05.006 |
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| 中文摘要:为给解析干旱胁迫下的碳、氮代谢调控机制提供参考，以玉米品种‘郑单958’为材料，在防雨棚中设置吐丝期后干旱胁迫和正常供水两个处理，测定不同部位碳、氮同化物含量及分配情况，碳、氮代谢关键酶活性及叶片基因表达谱差异。结果表明，干旱胁迫显著降低生物量在籽粒中的分配比例，可溶性糖、淀粉、全氮等在籽粒中的分配比例均显著降低，而茎秆和穗轴中的分配比例显著增加。干旱胁迫下生育后期叶片碳、氮同化物含量及分配比例均呈下降趋势，这与可溶性淀粉合成酶、谷氨酰胺合成酶等活性的改变有关。采用转录组测序对生育后期叶片差异基因表达进行了分析，共得到差异表达基因51个，这些基因富集在细胞壁组织、碳水化合物代谢、光合作用等代谢途径中。其中纤维素、木质素合成等关键酶基因在干旱胁迫下均显著下调表达，表明干旱胁迫抑制了细胞壁的合成，导致叶片早衰。干旱胁迫下己糖激酶、核糖体蛋白等基因显著下调表达，而甘露糖异构酶基因显著上调表达。综上所述，干旱胁迫抑制了生育后期碳、氮同化物向籽粒的分配，茎秆中的分配比例显著上升。干旱胁迫下叶片碳、氮同化物含量及分配比例显著降低，这与叶片早衰及相关碳氮代谢关键酶活性及基因表达的变化有关。 |
| 中文关键词:玉米 干旱胁迫 碳氮分配 基因表达 |
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| Effect of Drought Stress on Carbon and Nitrogen Allocation and Physiological Characteristics of Maize at Late Growth Stage |
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| Abstract:To provide reference for explore the carbohydrate and nitrogen metabolic regulation mechanisms of maize under drought stress,the maize variety ‘Zhengdan 958’ was used as material,two water treatments of drought stress (DS) and well water (WW) supply were set up in the rain-proof shed after the silking stage,which is expected to analyze the distribution of carbon and nitrogen assimilates,differences in enzyme activity of carbon and nitrogen metabolism and gene expression profiles in leaves.The results showed that drought stress significantly reduced the grain harvest index,and the carbon and nitrogen ratio of grain were decreased significantly,while the distribution ratios in stalk and cob were increased.The content and distribution rates of leaf carbon and nitrogen assimilates were reduced under drought stress,which may be associated with the changes in activities of soluble starch synthase (SSS) and glutamine synthetase in leaves.An RNA-Seq analysis was performed to analyze the differences in gene expressions under drought stress,and a total of 51 differentially expressed genes were obtained.These genes were significantly enriched in metabolic pathways such as cell wall organization,carbohydrate metabolism,and photosynthesis.The expression of fibre and lignin synthesis-related enzyme genes were significantly down-regulated under drought stress,which indicated that drought stress inhibited the synthesis of cell wall,and resulted in accelerated leaf senescence.The genes encoding hexokinase,and ribosomal proteins were significantly down-regulated under post-anthesis drought stress,while mannose isomerase genes were up-regulated.To sum up,drought stress inhibits the partitioning of carbon and nitrogen assimilates from vegetative tissue to the grains,which was associated with the increase of the partitioning rates in the stem.Leaf carbon and nitrogen assimilates were reduced under drought stress,and may be associated with the accelerated leaf senescence and alter enzyme activities and genes expression profiles of carbon and nitrogen metabolic pathways. |
| keywords:Maize Drought stress Carbon and nitrogen allocation Gene expression. |
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