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:
“But I would cry,
rooted into the wall that
was once my mother,
if I could remember how
and if I had the tears.”
—Anne Sexton (1928–1974)
“While ... we cannot and must not hide our concern for grave world dangers, and while, at the same time, we cannot build walls around ourselves and hide our heads in the sand, we must go forward with all our strength to stress and to strive for international peace. In this effort America must and will protect herself.”
—Franklin D. Roosevelt (1882–1945)
“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)