结论:催天花配子体茎的显着增厚的外部组织的超微结构设计和生化组织优化了茎的承重能力。Hypnodendronmenziesii是一种在高潮湿条件下生长在新西兰森林地面上的苔藓。直立的配子体连续承受多达八个轮枝,散布在具有高度水合叶子的重树枝上的茎上。我们使用光学显微镜的组合进行调查,透射电子显微镜(TEM),扫描电子显微镜(SEM),和TEM免疫标记技术提供了有关表皮大大增厚细胞壁的结构设计和生化组织的新信息,皮下,最外层的皮质组织,比较配子体茎中潜在的薄壁皮质组织。通过TEM和SEM探测这些靶组织的细胞壁结构的超微结构显示细胞壁显示多层组织,除了证明细胞壁中存在电子致密物质,大概是类黄酮。鼠李糖半乳糖醛酸的分布和浓度模式,高半乳糖醛酸,和异甘露聚糖,通过免疫金标记确定,这表明细胞壁的结构和分子设计的结合可以优化表皮的机械功能,皮下,和外层皮质组织.表皮总厚度之间的统计关系,皮下,和外层皮质细胞壁,这些组织在茎的不同高度处占据的细胞腔面积和细胞壁面积百分比,探索了次生细胞壁层(L1-L4/5)的厚度。这些分析的结果明确支持外部组织对弹性杆的机械强度的贡献。
CONCLUSIONS: The ultrastructural design and biochemical organization of the significantly thickened outer tissues of the gametophytic stem of Hypnodendron menziesii optimizes load bearing of the stem. Hypnodendron menziesii is a bryoid umbrella moss growing in high humid conditions on the forest floors of New Zealand. The erect gametophyte bears up to eight whorls of branches in succession, spreading across the stem that bears the heavy weight of branches with highly hydrated leaves. Our investigation using a combination of light microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and TEM-immunolabeling techniques provided novel information on the structural design and biochemical organization of greatly thickened cell walls of epidermal, hypodermal, and outermost cortical tissues, comparing underlying thin-walled cortical tissues in the gametophytic stem. Probing into the ultrastructure of the cell wall architecture of these target tissues by TEM and SEM revealed the cell walls to display a multilamellar organization, in addition to demonstrating the presence of an electron-dense substance in the cell wall, presumably flavonoids. The pattern of distribution and concentration of rhamnogalacturonan, homogalacturonan, and heteromannan, as determined by immunogold labeling, suggests that it is the combination of structural and molecular design of the cell wall that may optimize the mechanical function of the epidermal, hypodermal, and outer cortical tissues. Statistical relationships between the overall thickness of epidermal, hypodermal, and outer cortical cell walls, the lumen area of cells and the percentage area of cell wall occupied in these tissues at different heights of the stem, and thickness of secondary cell wall layers (L1-L4/5) were explored. The results of these analyses unequivocally support the contribution of outer tissues to the mechanical strength of the resilient stem.