title: Hydro-responsive curling of the resurrection plant Selaginella lepidophylla.
abstract: The spirally arranged stems of the spikemoss Selaginella lepidophylla, an ancient resurrection plant, compactly curl into a nest-ball shape upon dehydration. Due to its spiral phyllotaxy, older outer stems on the plant interlace and envelope the younger inner stems forming the plant centre. Stem curling is a morphological mechanism that limits photoinhibitory and thermal damages the plant might experience in arid environments. Here, we investigate the distinct conformational changes of outer and inner stems of S. lepidophylla triggered by dehydration. Outer stems bend into circular rings in a relatively short period of desiccation, whereas inner stems curl slowly into spirals due to hydro-actuated strain gradient along their length. This arrangement eases both the tight packing of the plant during desiccation and its fast opening upon rehydration. The insights gained from this work shed light on the hydro-responsive movements in plants and might contribute to the development of deployable structures with remarkable shape transformations in response to environmental stimuli.
authors.affiliation: Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montréal, QC, H3A OC3, Canada.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Rafsanjani
authors.affiliation: Biology Department, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, H3A 1B1, Canada.
authors.forename: Véronique
authors.initials: V
authors.lastname: Brulé
authors.affiliation: Biology Department, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, H3A 1B1, Canada.
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Western
authors.affiliation: Mechanical Engineering Department, McGill University, 817 Sherbrooke Street West, Montréal, QC, H3A OC3, Canada.
authors.forename: Damiano
authors.initials: D
authors.lastname: Pasini
mesh_terms: D020342:Finite Element Analysis; D018547:Plant Stems / Q000502:physiology; D032503:Selaginellaceae / Q000378:metabolism*; D014741:Video Recording; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water