Table_1_Insights Into the Inside – A Quantitative Histological Study of the Explosively Moving Style in Marantaceae.docx

This study aims to identify the histological basis for the extraordinary, fast movement of the style in Marantaceae. Although this explosive pollination mechanism was subject of many studies, quantitative measurements to document volumetric changes have never been conducted. Based on physical parameters and limitations (poroelastic time), the movement itself is by far too fast to be explained by turgor changes solely. Therefore, we address the hypothesis that the style contains elastic structures to store energy allowing the fast movement. We provide an experimental approach in Goeppertia bachemiana to identify histological differences of styles in various states, i.e., steady, unreleased, and released state. Cross and longitudinal sections were used to reconstruct the cell volume in different sectors of the style. Histological data were discussed with respect to a putative water shift (turgor movement) and elastic instabilities that were proposed to explain the style movement of Marantaceae. Current data show, that the upper epidermis is under tensile stress in the unreleased state. After style release, the lower side of the style revealed an enormous water up-take. According to our results, we hypothesize that the fast style movement of G. bachemiana is likely based on an elastically stretched upper epidermis, whereas a “soaking tissue” at the lower side presumably mediates the up curling of the style. The experimental data show that at least for G. bachemiana, physical limitations such as the poroelastic time are suitable parameters to predict movements that are based on elastic instabilities.

本研究旨在探究马鞭草科植物花柱异常快速运动的组织学基础。尽管这一爆炸式传粉机制已成为众多研究的对象，但从未进行过定量测量以记录体积变化。基于物理参数和局限性（多孔弹性时间），花柱的运动本身过于快速，无法仅由膨压变化来解释。因此，我们提出假设，花柱含有弹性结构以储存能量，从而允许快速运动。我们通过在Goeppertia bachemiana中进行实验，以识别花柱在不同状态下的组织学差异，即稳定状态、未释放状态和释放状态。通过横切和纵切面，我们重建了花柱不同部位的细胞体积。在讨论组织学数据时，我们考虑了推测的水位移动（膨压运动）和弹性不稳定性，这些不稳定性被提出用以解释马鞭草科植物的花柱运动。当前数据显示，在未释放状态下，上部表皮承受拉伸应力。在花柱释放后，花柱下侧表现出巨大的水分吸收。根据我们的研究结果，我们假设G. bachemiana中花柱的快速运动可能基于弹性拉伸的上部表皮，而下侧的“吸水组织”可能介导花柱的上卷。实验数据表明，至少对于G. bachemiana而言，物理限制如多孔弹性时间，是预测基于弹性不稳定性的运动的合适参数。