Flax (Linum usitatissinum L.) is an economically important fiber crop species as it produces long cellulosic fibers with high tensile strength. The first step in flax fiber extraction occurs after harvest via a process known as dew retting in which pulled (uprooted) plants are placed on the soil. During this process microorganisms from the soil and the phyllosphere develop on the plants, leading to partial decomposition of the stem tissues and facilitated mechanical extraction and improved fiber quality. Despite its importance, the management of dew retting is mainly based on empirical knowledge that makes the process difficult to control. In this study the dynamics of flax dew retting were investigated for the first time by combining targeted-metagenomics (metabarcoding), enzymatic activities and chemical and microscopic characterization of the stem. This multimodal approach indicated that intensive microbial colonization and major chemical changes in the stem cell wall composition occurred during the first weeks of retting leading to progressive fiber bundle decohesion in the outer stem tissues. The main changes could be explained by the degradation of pectin-rich and non-lignified thin walls of both the parenchyma cells surrounding fiber bundles, and the differentiating xylem and cambial cells. Field emission scanning electron microscopy suggested that the ultrastructure of the fiber secondary wall is weakly impacted by dew-retting. Analyses indicated that the mechanical properties of extracted technical fibers were improved during the last retting stages. Overall data on thermoplastic composites produced by a twin-screw extrusion and injection molding processes suggested that the retting degree had a small but significant effect on tensile properties.

亚麻（亚麻usitatissinumL.）是一种经济上重要的纤维作物品种，因为它生产具有高拉伸强度的长纤维素纤维。亚麻纤维提取的第一步是在收获后通过称为“露露”的过程进行的，在该过程中，将拔出的（连根拔起的）植物放在土壤上。在此过程中，来自土壤和叶际的微生物在植物上生长，导致茎组织的部分分解，并促进了机械提取并改善了纤维质量。尽管非常重要，但露水管理主要基于经验知识，这使得过程难以控制。在这项研究中，首次通过结合目标基因组学（元条形码），酶促活性以及茎的化学和微观表征，研究了亚麻露的动态。这种多峰方法表明，在re缩的最初几周内，干细胞壁成分发生了强烈的微生物定植和主要化学变化，从而导致外部茎组织中纤维束逐渐脱粘。主要的变化可以通过围绕纤维束的薄壁组织细胞以及分化的木质部和角质层细胞的富含果胶和未木质化的薄壁的降解来解释。场发射扫描电子显微镜表明，纤维二次壁的超微结构受结露的影响很小。分析表明，提取的工业纤维的机械性能在最后的脱胶阶段得到了改善。