Barthlott Wilhelm, Büdel Burkhard, Mail Matthias, Neumann Klaus Michael, Bartels Dorothea, Fischer Eberhard
Nees Institute for Biodiversity of Plants, University of Bonn, Bonn, Germany.
Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany.
Front Plant Sci. 2022 May 24;13:880439. doi: 10.3389/fpls.2022.880439. eCollection 2022.
Plants and other organisms have evolved structures and mechanisms for colonizing land since the Early Ordovician. In this context, their surfaces, the crucial physical interface with the environment, are mainly considered barriers against water loss. It is suggested that extreme water repellency (superhydrophobicity) was an additional key innovation for the transition of algae from water to land some 400 mya. Superhydrophobicity enhances gas exchange on land and excludes aquatic competitors in water films. In a different context, in material science and surface technology, superhydrophobicity has also become one of the most important bioinspired innovations enabling the avoidance of water films and contamination. Here, we present data for an extremely water-repellent cyanobacterial biofilm of the desiccation tolerant providing evidence for a much earlier prokaryotic Precambrian (ca. 1-2 bya) origin of superhydrophobicity and chemical heterogeneities associated with land transition. The multicellular cyanobacterium is functionally differentiated in a submerged basal hydrophilic absorbing portion like a "rhizoid" and an upright emersed superhydrophobic "phyllocauloid" filament for assimilation, nitrogen fixation, and splash dispersed diaspores. Additional data are provided for superhydrophobic surfaces in terrestrial green algae and in virtually all ancestral land plants (Bryophytes, ferns and allies, , ), slime molds, and fungi. Rethinking of superhydrophobicity as an essential first step for life in terrestrial environments is suggested.
自早奥陶世以来，植物和其他生物已经进化出了在陆地上定殖的结构和机制。在这种情况下，它们的表面作为与环境的关键物理界面，主要被视为防止水分流失的屏障。有人认为，极端疏水性（超疏水性）是约4亿年前藻类从水生向陆生转变的另一项关键创新。超疏水性增强了陆地的气体交换，并排除了水膜中的水生竞争者。在另一种情况下，在材料科学和表面技术中，超疏水性也已成为最重要的仿生创新之一，能够避免水膜和污染。在这里，我们展示了一种耐干燥的极端疏水蓝藻生物膜的数据，为超疏水性和与陆地转变相关的化学异质性在更早的前寒武纪原核生物（约10亿至20亿年前）起源提供了证据。这种多细胞蓝藻在功能上分化为一个像“假根”一样的浸没在水下的基部亲水吸收部分，以及一个直立露出水面的超疏水“叶茎状”细丝，用于同化、固氮和通过飞溅传播的传播体。还提供了陆地绿藻以及几乎所有原始陆地植物（苔藓植物、蕨类植物及其近缘植物）、黏菌和真菌中超疏水表面的其他数据。有人建议将超疏水性重新视为陆地环境中生命的重要第一步。
