BACKGROUND AND AIMS Fruit pedicels have to deal with increasing loads after pollination due to the continuous growth of the fruits. Thus, they represent interesting tissues from a mechanical as well as developmental point of view. However, only few studies exist on fruit pedicels. In this study, we unravel the anatomy and structural-mechanical-relationships of the pedicel of Adansonia digitata reaching up to 90 cm in length. METHODS Morphological and anatomical analyses included the examination of stained cross sections from various positions along the stalk as well as X-ray micro-tomography (µ-CT) and scanning electron microscopy (SEM). For mechanical testing, fiber bundles derived from the mature pedicels were examined via tension tests. For establishing the structural-mechanical relationships, density of the fiber bundles as well as their cellulose microfibril distribution and chemical composition were analyzed. KEY RESULTS While in the peduncle the vascular tissue and the fibers are arranged in a concentric ring like way, this organization shifts to the polystelic structure of separate fiber bundles in the pedicel. The polystelic pedicel possesses five vascular strands that consist of strong bast fiber bundles. The fiber bundles reveal a Young´s modulus of up to 5 GPa, a tensile strength of up to 400 MPa, a high density (>1g/cm-3), and a high microfibril angle of around 20°. CONCLUSIONS The structural arrangement as well as the combination of high density and high microfibril angle of the bast fiber bundles are most likely optimized for bearing considerable strains in torsion and bending while at the same time allowing for carrying high tension loads.

中文翻译：

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猴面包树果梗的功能原理——解剖学和生物力学

背景和目的 由于果实的持续生长，授粉后果梗必须处理增加的负荷。因此，从机械和发育的角度来看，它们代表了有趣的组织。然而，关于果梗的研究很少。在这项研究中，我们解开了长达 90 厘米的 Adansonia digitata 花梗的解剖结构和结构-机械关系。方法 形态学和解剖学分析包括检查沿茎的不同位置的染色横截面以及 X 射线显微断层扫描 (μ-CT) 和扫描电子显微镜 (SEM)。对于机械测试，通过拉伸测试检查源自成熟花梗的纤维束。为了建立结构-机械关系，分析了纤维束的密度以及它们的纤维素微纤丝分布和化学成分。主要结果 虽然在花梗中，维管组织和纤维以同心环的方式排列，但这种组织转移到花梗中分离纤维束的多丝结构。Polystelic 花梗具有五个维管束，由强韧的韧皮纤维束组成。纤维束显示出高达 5 GPa 的杨氏模量、高达 400 MPa 的拉伸强度、高密度 (>1g/cm-3) 和约 20° 的高微纤维角。