Wall stress relaxation refers to the reduction in tensile stress (force per unit area) in cell walls of plants, fungi and bacteria, as a result of movement or rearrangement of the polymeric network that gives the wall its tensile strength. Wall stress usually comes from cell hydrostatic pressure or turgor pressure, which stretches the cell wall. The wall's resistance to stretching simultaneously creates wall stress and its counter force, turgor pressure. In plant cells, the wall-loosening protein named expansin causes wall stress relaxation by loosening the connections between cellulose microfibrils. The resulting decrease in cell turgor pressure and cell water potential creates the necessary water potential gradient that allows water uptake and expansion of the cell.
Famous quotes containing the words wall, stress and/or relaxation:
“What a troublesome thing a wall is! I thought it was to defend me, and not I it! Of course, if they had no wall, they would not need to have any sentinels.”
—Henry David Thoreau (1817–1862)
“Anyone who wishes to combine domestic responsibilities and paid employment with the least stress and most enjoyment might start by pondering this paradox: the first step to better functioning is to stop blaming herself for not functioning well enough.”
—Faye J. Crosby (20th century)
“Worst of all, there is no sign of any relaxation of antisemitism. Logically it has nothing to do with Fascism. But the human race is imitative rather than logical; and as Fascism spreads antisemitism spreads.”
—George Bernard Shaw (1856–1950)