Growing plant cells require pressure from the cell to press on the cell wall to make it elongate as it is being formed. When young, expanding cells are not turgid, there is no pressure on the cell wall to make the wall elongate, it becomes thickened instead The thickening will actually make a plant stem or leaf stronger provided it does not occur for such a long period of time that there is damage to the growing cell. Called drying down or hardening a plant. Can be a very effective strategy in raising crops where water applications can be controlled. Oldest and cheapest method of controlling plant growth.
Caution verrrrry fine line between drying down and drying up a young plant.