  The microscopic structure of a plant cell wall is given by cellulose
microfibrils embedded in a cell wall matrix. In this paper we consider a
microscopic model for interactions between viscoelastic deformations of a plant
cell wall and chemical processes in the cell wall matrix. We consider elastic
deformations of the cell wall microfibrils and viscoelastic Kelvin--Voigt type
deformations of the cell wall matrix. Using homogenization techniques
(two-scale convergence and periodic unfolding methods) we derive macroscopic
equations from the microscopic model for cell wall biomechanics consisting of
strongly coupled equations of linear viscoelasticity and a system of
reaction-diffusion and ordinary differential equations. As is typical for
microscopic viscoelastic problems, the macroscopic equations for viscoelastic
deformations of plant cell walls contain memory terms. The derivation of the
macroscopic problem for degenerate viscoelastic equations is conducted using a
perturbation argument.
