title: Hierarchies of plant stiffness.
abstract: Plants must meet mechanical as well as physiological and reproductive requirements for survival. Management of internal and external stresses is achieved through their unique hierarchical architecture. Stiffness is determined by a combination of morphological (geometrical) and compositional variables that vary across multiple length scales ranging from the whole plant to organ, tissue, cell and cell wall levels. These parameters include, among others, organ diameter, tissue organization, cell size, density and turgor pressure, and the thickness and composition of cell walls. These structural parameters and their consequences on plant stiffness are reviewed in the context of work on stems of the genetic reference plant Arabidopsis thaliana (Arabidopsis), and the suitability of Arabidopsis as a model system for consistent investigation of factors controlling plant stiffness is put forward. Moving beyond Arabidopsis, the presence of morphological parameters causing stiffness gradients across length-scales leads to beneficial emergent properties such as increased load-bearing capacity and reversible actuation. Tailoring of plant stiffness for old and new purposes in agriculture and forestry can be achieved through bioengineering based on the knowledge of the morphological and compositional parameters of plant stiffness in combination with gene identification through the use of genetics.
authors.affiliation: Department of Biology, McGill University, 1205 Docteur Penfield Ave., Montreal, QC, H3A 1B1, Canada. Electronic address: veronique.brule@mail.mcgill.ca.
authors.forename: Veronique
authors.initials: V
authors.lastname: Brulé
authors.affiliation: Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC, H3A OC3, Canada. Electronic address: ahmad.rafsanjani@mail.mcgill.ca.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Rafsanjani
authors.affiliation: Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC, H3A OC3, Canada. Electronic address: damiano.pasini@mcgill.ca.
authors.forename: Damiano
authors.initials: D
authors.lastname: Pasini
authors.affiliation: Department of Biology, McGill University, 1205 Docteur Penfield Ave., Montreal, QC, H3A 1B1, Canada. Electronic address: tamara.western@mcgill.ca.
authors.forename: Tamara L
authors.initials: TL
authors.lastname: Western
mesh_terms: D017360:Arabidopsis / Q000502:physiology; D001696:Biomechanical Phenomena; D002473:Cell Wall / Q000502:physiology*; D018521:Plant Physiological Phenomena
keywords: Arabidopsis thaliana; Bioengineering; Plant biomechanics; Plant cell walls; Plant stiffness; Stiffness gradients