US National Weather Service Philadelphia September Weather data records that on September 28, 1984, the high temperature did not exceed 52 degrees Fahrenheit, the lowest high measured in Philadelphia in the past 69 years.
Vacuoles are generally used to store cell products or protect the rest of the cell from invading microorganisms. The large central vacuole of plant cells is a special case. It is used to store water and cellular wastes and helps maintain the necessary internal pressure of plants called turgor pressure. Structure.
Turgor in Plants. Plant cells are surrounded by rigid cell walls. When plant cells are exposed to hypotonic environments, water rushes into the cell, and the cell swells, but is kept from breaking by the rigid wall layer. The pressure of the cell pushing against the wall is called turgor pressure, and is the desired state for most plant tissues. For instance, placing a wilted celery stalk or lettuce leaf in a hypotonic environment of pure water, will often revive the leaf by inducing turgor in the plant cells.