The plant cell wall is made up of hydrated polymetric material, allowing it to have viscoelastic properties.[1] The primary cell wall of a plant consists of cellulose fibers, hemicellulose, and xyloglucans.[2] This load bearing network is also surrounded by pectins and glycoproteins.
Wall stress relaxation is an important factor in cell wall expansion. Wall stress (measured in force per unit area) is created in response to the plant cell's turgor pressure.[2] Turgor pressure creates tension in the cell walls of plants, fungi, and bacteria, as it opposes the pressure of the cell's primary cell wall; this also allows for stretching of the cell wall.[1] The stretching of the cell wall, or the reduction of stress, occurs as a result of cell expansion and rearrangement. Cell expansion is crucial for the reshaping and rearranging of plant cells.[1] Expansion is the result of "creep", or selective wall loosening, which is driven by turgor pressure. During this "creep", cellulose microfibers move relative to each other creating an irreversible extension [2]