Question

Water pressure in stems and leaves helps to

Answer 1

When there is water in the cell of a stem or leaves, the cytoplasm swells up and creates a pressure against its cell walls. That cell pushes against its surrounding cells. Those surrounding cells exert a pressure in the cells surrounding them and so on. This pressure is known as turgid pressure, and it keeps the non-woody parts of the plant, such as the leaves and the stem, upright and rigid.
When a cell loses enough water to become flaccid, the cytoplasm starts to peel away from the cell wall. Its cytoplasm no longer exerts a pressure on its cell wall. Therefore the cell no longer exerts a pressure on its surrounding cells, who don’t exert a pressure on the cells surrounding them. This lack of pressure causes the plant to wilt.
Hope this helps!

Answer 2

Answer:

When the soil of a plant runs too low of available water, the water chains in the xylem become thinner and thinner due to less water. Effectively, the plant is losing water faster than it is absorbing it. When this happens, the plant loses its turgidity and begins to wilt.