The functional morphology of the petioles of the banana, Musa textilis
The functional morphology of the petioles of the banana, Musa textilis
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DOI：
10.1093/jexbot/51.353.2085
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发表时间：
2000-12-01
影响因子：
6.9
通讯作者：
Speck, T
中科院分区：
文献类型：
--
作者：
Ennos, AR;Spatz, HC;Speck, T
香蕉是世界上最大的草本植物之一，它们轻巧的叶柄支撑着巨大的叶子，这项研究研究了叶柄如何实现足够的刚度，同时允许在大风中进行广泛和可逆的重新配置。梅萨特克斯的叶柄和叶的形态和解剖学检查表明，这两个明显不相容的能力是如何实现的。叶柄的中空U形部分和其外层的纵向加强元件使其具有足够的刚度，而其腹侧弯曲有助于支撑叶片，而不需要厚的侧脉。然而，这些特征也允许叶柄通过扭转来重新配置，而叶子可以折叠。此外，两套内部结构，纵向分区和横向星状薄壁组织板，有助于防止背腹扁平，使叶柄弯曲远离风没有屈曲。这些想法通过一系列机械测试进行了测试和验证。简单的四点弯曲和扭转测试表明，叶柄在扭转方面的顺应性确实远高于弯曲。轴向弯曲试验和挤压试验表明，叶柄可以弯曲的两倍远，是四倍的抗背腹压扁时，完整时比当内部组织被删除，香蕉叶柄，因此，似乎是一个很好的例子，自然集成的机械设计。
Bananas are among the largest herbs in the world and their lightweight petioles hold up huge leaves, This study examined how the petioles manage to achieve adequate rigidity to do this, while allowing extensive and reversible reconfiguration in high winds. Morphological and anatomical examination of the petioles and leaves of Mesa textilis suggested how these two apparently incompatible abilities are achieved. The hollow U-shaped section of the petiole and the longitudinal strengthening elements in its outer skin give it adequate rigidity, while its ventral curvature help support the leaf without the need for thick lateral veins. These features, however, also allow the petiole to reconfigure by twisting away from the wind, while the leaf can fold away. In addition, two sets of internal structures, longitudinal partitions and transverse stellate parenchyma plates, help prevent dorsoventral flattening, allowing the petiole to flex further away from the wind without buckling. These ideas were tested and verified by a range of mechanical tests. Simple four-point-bending and torsion tests showed that the petioles are indeed far more compliant in torsion than in bending. Axial bending tests and crushing tests showed that petioles could be flexed twice as far and were four times as resistant to dorsoventral flattening when intact than when the internal tissue is removed, The banana petiole, therefore, seems to be an excellent example of natural integrated mechanical design.