Table_1_Mind the Gap: Reach and Mechanical Diversity of Searcher Shoots in Climbing Plants.DOCX

Climbing plants need to reach supports and position their leaves for light capture. Vines and lianas develop a large diversity of self-supporting shoots among diverse species and different kinds of attachment. A searcher’s reach is a crucial trait for colonising supports in complex three-dimensional spaces. We explore the reach capacity and diversity of searcher shoots among representative temperate and tropical climbing plants. We investigate the overall range of variation between short- and long-reach searchers; the mechanical and anatomical organisations underlying reach capacities; how searcher architectures are linked to different climbing strategies such as stem twining, tendril climbing, root climbing, and branch-angle-hook climbing. We investigated reach and mechanical and anatomical organisations (stem rigidity and stiffness, stem and tissue geometry) in 29 climbing plant species from temperate and tropical habitats. Searchers show a wide range of maximal reach per species from 0.1 to 2.5 m. Flexural rigidity (EI) at the base of searchers increased with reach length; overall this increase was proportional although some longest-reaching shoots develop proportionally thinner searcher bases with higher stiffness [structural Young’s modulus (Estr)] than shorter-reach shoots. Bases of short-reach searchers rely more on primary tissues compared to long-reach shoots, which rely more on wood production. We identified different mechanical architectures for a given reach capacity across all species. These are linked to different kinds of attachment mechanisms, support foraging, and possibly leaf display. Plants attaching by twining of the main stem showed a wide range of reach capacity. They also developed lighter, more slender, less rigid, but generally relatively stiff (higher Estr) shoots compared with tendril climbers and branch-angle-hook climbers. Differences in the mechanical architecture of searcher shoots in climbing plants are informative for understanding how diverse climbing plant species explore and colonise different kinds of three-dimensional spaces. This is a key feature that distinguishes different habitat preferences. We discuss how such knowledge is not only important for understanding functional biology and ecology of climbing plants but is also of interest for developing new technologies in soft robotics that mimic climbing plants that can navigate through unstructured environments.

攀缘植物需触及支撑物并定位其叶片以捕捉光线。不同物种和不同类型的附着方式下，葡萄藤和木质藤本植物发展出多样化的自支撑枝条。搜索者的伸展范围是殖民复杂三维空间支撑物的关键特征。我们探讨了代表性温带和热带攀缘植物中搜索者枝条的伸展能力和多样性。我们研究了短距离和长距离搜索者之间的整体变异范围；支撑能力背后的机械和形态组织；搜索者结构如何与不同的攀爬策略如茎缠绕、卷须攀爬、根攀爬和枝角钩攀爬相联系。我们调查了来自温带和热带栖息地的29种攀缘植物中搜索者的伸展、机械和形态组织（茎的刚度和刚度、茎和组织几何形状）。搜索者展现出从0.1到2.5米的广泛最大伸展范围。搜索者基部的弯曲刚度（EI）随着伸展长度的增加而增加；总体而言，这种增加是成比例的，尽管一些最长伸展的枝条发展出成比例更细的搜索者基部，具有更高的刚度[结构杨氏模量（Estr）]而非短距离伸展的枝条。与长距离伸展相比，短距离搜索者的基部更依赖于初生组织。我们确定了所有物种给定伸展能力下的不同机械结构，这些结构与其不同的附着机制、支持觅食以及可能的叶片展示相关联。通过主茎缠绕附着的植物展现出广泛的伸展能力。它们还发展出更轻、更细、更不僵硬但总体上相对刚硬（更高的Estr）的枝条，与卷须攀爬者和枝角钩攀爬者相比。攀缘植物中搜索者枝条机械结构的不同，对于理解不同攀缘植物物种如何探索和殖民不同类型的立体空间具有重要意义。这是区分不同栖息地偏好的关键特征。我们讨论了此类知识不仅对于理解攀缘植物的功能生物学和生态学至关重要，而且对于开发模仿攀缘植物的新软体机器人技术，使其能够在非结构化环境中导航也具有重要意义。