The flow of nutrient solutions in hydroponics markedly affects plant growth and development. Suitable flow rates can improve root morphology, facilitating nutrient absorption. Altered cell wall composition upon sensing external stimuli can promote environmental adaptation. Lignin, an important plant cell wall component, enhances structural strength; however, the effects of nutrient solution flow on lignin synthesis remain unexplored. Here, we applied high-throughput metabolomic, transcriptomic, and proteomic techniques to systematically study hydroponically grown lettuce (Lactuca sativa), revealing significant regulatory effects of nutrient solution flow on lignin metabolism in lettuce roots. Gene and protein expression differed in lettuce roots under different flow rates, consistent with the underlying molecular mechanisms elucidated by metabolomic analyses. Specifically, under no-flow conditions, the contents of p-coumaryl alcohols (H-lignin) and coniferyl alcohols (G-lignin) were elevated, whereas high-flow conditions upregulated sinapyl alcohols synthesizing S-lignin. Moreover, lignin synthesis-related HCT, CAD, and PER gene families were highly expressed under no-flow and high-flow conditions, with coordinate changes in lignin content, indicating that nutrient flow influenced their expression; thereby affecting root cell lignin content. This study enhances our understanding of plant growth and secondary metabolic regulatory mechanisms in hydroponic environments and lays a theoretical foundation for optimizing plant growth conditions in hydroponic systems.

中文翻译：

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水培养分流动环境对生菜根木质素生物合成影响的多组学分析


水培法中营养液的流动显着影响植物的生长和发育。合适的流速可以改善根系形态，促进养分吸收。感知到外部刺激后细胞壁组成的改变可以促进环境适应。木质素是一种重要的植物细胞壁成分，可增强结构强度;然而，营养液流动对木质素合成的影响仍未得到探索。在这里，我们应用高通量代谢组学、转录组学和蛋白质组学技术系统研究水培生菜 （Lactuca sativa），揭示了营养液流动对生菜根系木质素代谢的显着调节作用。在不同流速下，生菜根的基因和蛋白质表达不同，这与代谢组学分析阐明的潜在分子机制一致。具体而言，在无流条件下，对香豆酰醇 （H-木质素） 和针叶醇 （G-木质素） 的含量升高，而高流速条件下合成 S-木质素的芥子醇含量上调。此外，木质素合成相关的 HCT 、 CAD 和 PER 基因家族在无流和高流条件下均高表达，木质素含量的坐标变化表明营养流影响了它们的表达;从而影响根细胞木质素含量。本研究增强了我们对水培环境中植物生长和次生代谢调控机制的理解，并为优化水培系统中的植物生长条件奠定了理论基础。