Robert Palin, Jeremy Pritchard, Colin Thomas
University of Birmingham

Introduction
The relationship between the composition and architecture of the primary plant cell wall, and its mechanical properties is not fully understood. The elasticity, plasticity and strength of the primary plant cell wall are presumed to arise primarily from a network of the cellulose microfibrils, cross-linked with hemi-cellulose, and interpenetrated by pectin. It is known that changes in the composition and architecture of the cell wall lead to detectable differences in the mechanical properties. In this work, a comparison was made to the mechanical properties of cell walls of A. thaliana wild type and a selection of cell wall mutants grown in suspension cultures. Relationships between suspension culture propertied, shoot and root growth characteristics and wall composition were sought.

Cell wall mutants
Three cell wall mutations (IDA, Mur1 and Snakeskin) were investigated and compared to the Columbia wild type. Shoot and root growth was characterised to evaluate the effects of the mutations on plant growth.
To produce viable single cells for use in micro-compression, callus cells were grown from root sections and transferred to liquid culture media and kept at a constant temperature and rotated. The viability of the cells was proven using neutral red staining.

Compression testing by Microcompression
Force-deformation data were obtained by compression testing using micro-manipulation. Mathematical modelling was used to estimate the low strain elastic modulus of the cell walls, and the (pseudo) stress at wall failure.

Comparison of the Cell Wall Composition
The composition of the cell wall will be obtained from sequentially extracting polymers from the cell walls of suspension cultured cells and hydroponically grown the Arabidopsis mutants. Analysis by spectrophotometry and paper chromatography will allow the quantification of the differences between the mutants and those grown under different growth conditions.