The fluid in the vacuole of a plant cell is called cell sap.


Cell sap refers to the fluid present in the vacuole of a plant cell. The vacuole is a large membrane-bound organelle found in plant cells, and it occupies a significant portion of the cell's volume. The cell sap is contained within the vacuole and plays various roles in the plant cell's functioning.


The cell sap is primarily composed of water, which makes up the majority of its content. Additionally, it contains various dissolved substances such as sugars, organic acids, enzymes, amino acids, salts, pigments, and secondary metabolites. These substances are responsible for the characteristic color, taste, and smell of fruits and flowers.


The cell sap performs several important functions in a plant cell:

1. Storage: The vacuole and its sap act as a storage compartment for various substances. It stores water, nutrients, minerals, and waste products that are not immediately needed by the cell. This enables the plant to regulate its water balance and maintain turgidity, which is crucial for maintaining the structural integrity of the plant.

2. Turgor pressure: The cell sap contributes to the turgor pressure of the plant cell. Turgor pressure is the pressure exerted by the cell contents against the cell wall, and it helps maintain the shape and rigidity of the plant. When the vacuole is filled with water, it creates internal pressure that pushes against the cell wall, providing support to the plant.

3. Transport: The vacuole and its contents are involved in the transport of various substances within the plant. The vacuole stores and transports ions, sugars, and other compounds throughout the cell. It also plays a role in the long-distance transport of water and nutrients within the plant's vascular system.

4. Defense: The cell sap can contain toxic compounds and secondary metabolites that help defend the plant against herbivores, pathogens, and other stressors. These compounds can deter or inhibit the growth of potential threats, contributing to the plant's defense mechanism.

5. Pigmentation: Some plant cell saps contain pigments that give color to flowers, fruits, and other plant parts. These pigments attract pollinators, aid in seed dispersal, and provide visual cues for various ecological interactions.

In conclusion, the fluid in the vacuole of a plant cell is called cell sap. It is a vital component of the plant cell, serving functions such as storage, turgor pressure maintenance, transport, defense, and pigmentation.