Bouldering: an alternative strategy to long-vertical climbing in root-climbing hortensias

In the Neotropics, the genus Hydrangea of the popular ornamental hortensia family is represented by climbing species that strongly cling to their support surface by means of adhesive roots closely positioned along specialized anchoring stems. These root-climbing hortensia species belong to the nearly exclusive American Hydrangea section Cornidia and generally are long lianescent climbers that mostly flower and fructify high in the host tree canopy. The Mexican species Hydrangea seemannii, however, encompasses not only long lianescent climbers of large vertical rock walls and coniferous trees, but also short ‘shrub-like’ climbers on small rounded boulders. To investigate growth form plasticity in root-climbing hortensia species, we tested the hypothesis that support variability (e.g. differences in size and shape) promotes plastic responses observable at the mechanical, structural and anatomical level. Stem bending properties, architectural axis categorization, tissue organization and wo...在新热带区（Neotropics），广受欢迎的观赏花卉八仙花科（hortensia family）下的绣球花属（Hydrangea），存在一类攀援物种：它们依靠沿特化固定茎紧密排布的黏附根牢牢附着于支撑表面。这类具根攀援习性的绣球花物种，几乎全部隶属于美洲绣球花专属的角柱组（Cornidia），多为大型藤本攀援植物，通常在寄主树冠的高处开花结果。然而，墨西哥原生的塞曼绣球（Hydrangea seemannii），不仅包含攀附于大型垂直岩壁与针叶树的长藤本攀援个体，还存在生长于小型圆形砾石上的矮化"灌木状"攀援个体。为探究具根攀援习性的绣球花物种的生长型可塑性，本研究检验了如下假说：支撑物的异质性（如尺寸与形态差异）可诱导出可在机械、结构及解剖层面观测到的可塑性响应。本研究对茎的弯曲特性、茎轴结构分类、组织构造以及...