Leaf evolution in pleurocarpous mosses – structural solutions in cellular monolayers

  • Bell, Neil, (Osallistuja)

Projektin yksityiskohdat

Kuvaus

The phyllodes (“leaves”) of mosses are independently derived and phylogenetically analogous to tracheophyte leaves, having evolved under similar constraints as organs for maximising projected surface area. However as structures they are fundamentally different, being mostly cellular monolayers with limited or no tissue differentiation. While some species have localised multilayered structural tissue, e.g. nerves and leaf borders, others are supported only by the lattice formed from individually thickened cell walls and possibly by leaf surface geometry. Many of these features clearly also have roles in water transport and retention. There is a huge diversity of leaf morphology in mosses, not least in the pleurocarps, which comprise about a third of all species.

We plan to examine correlated evolution of pleurocarpous moss leaf structural features in a phylogenetic context, identify primary associations of characters as hypotheses of unified functional structure or architectural types, and study the biomechanical properties (e.g. flexural stiffness, strength) of a range of different representative leaves. We will also reconstruct ancestral states for leaf structural features at critical nodes and test for convergent evolution of discrete types. We hypothesise that there are a limited number of structural solutions to the problem of supporting a leaf cellular monolayer and that these are well separated in morphospace, despite probably having arisen independently on multiple occasions.

The project will incorporate a small genomics component aimed at sequencing a limited number of chloroplast genomes for the purpose of identifying regions that could be used to resolve phylogeny in the largest pleurocarpous moss order, the Hypnales. Collaborative biomechanical research will utilise state-of-the-art industrial instruments and will be aimed at quantifying variables such as Young’s modulus and breaking stress. The result will be a unified model of pleurocarpous moss leaves as evolved biological structures that will greatly contribute to systematics, but will also have relevance to other disciplines where it is necessary to understand morphological and functional homology within mosses and between mosses and tracheophytes. We further anticipate that the project will be relevant to engineers and architects interested in biomimetics, as mosses have thoroughly explored the structural potential of cellular lattices during the course of their long evolution.
TilaPäättynyt
Todellinen alku/loppupvm01/09/201231/08/2017

Tieteenalat

  • 1181 Ekologia, evoluutiobiologia
  • 1183 Kasvibiologia, mikrobiologia, virologia
  • 119 Muut luonnontieteet