The vacuole is the main storage compartment in a plant cell and is responsible for storing water.

Here's why:

* Large Size: Vacuoles can occupy up to 90% of the cell's volume, giving them a huge capacity for water storage.

* Turgor Pressure: The water stored in the vacuole creates turgor pressure, which helps maintain the plant's rigidity and structure.

* Other Functions: Besides water, vacuoles also store nutrients, waste products, and pigments.

So, while other parts of the cell may hold some water, the vacuole is the primary water storage organelle in plant cells.