Function of a Vacuole in a Plant Cell

Have you ever had a garden vegetable, like a cucumber, that didn’t get rain, and it withered up and died?

Water is required for plant growth and development. Plants, like a cucumber, are made up of eukaryotic cells, which means they contain a nucleus and membrane-bound organelles . One essential organelle in a plant cell is the vacuole. The membrane surrounding a plant vacuole is called the tonoplast .

Vacuoles store water

Vacuoles in plant cells are large because their main function is to store water for the plant. The central vacuole in a plant cell can take up to 30 to 90 percent of the area of the cell. If you look at a plant cell under a microscope, the central vacuole looks like a bubble.

Water is vital for the plant cell for daily processes, but also provides support for the plant. If the plant does not have sufficient water stored in the vacuoles, the plant will wilt.

How does the water support the plant? Water stored in the central vacuole applies pressure to the cell wall when the vacuole is full. This is called turgor pressure . Turgor pressure keeps the plant upright.

Water gets inside the plant cell with help from the cell membrane. The water concentration changes in the plant through the process of osmosis . During osmosis, water molecules move across a selectively permeable membrane , in this case, the plant cell membrane. The water molecules move from an area of high concentration to an area of low concentration. The water is then stored in the vacuoles where it applies the turgor pressure.

Vacuoles store necessary materials

Plant vacuoles store carbohydrates like sucrose, glucose, and fructose. Plants use these sugars to grow and develop. One benefit is that humans and animals can then eat the plant’s seeds, roots, or stalks for their nutrition.

Calcium is a mineral that plants need for the structure of their cell walls . Calcium is stored in the cytoplasm or the vacuoles.

Vacuoles store pigments

Plant vacuoles contain specialized pigments, giving flowers their distinctive colors that attract pollinators . Specialized pigments, called anthocyanins , which are stored in plant vacuoles give foods red, orange, violet, and blue colors. Examples of foods containing these colors are blueberries, blackberries, strawberries, cherries, and blood oranges.

These foods are healthy options for us. We also benefit from other materials stored in plant vacuoles, like latex and rubber.

Vacuoles protect the plant

Plants have defensive adaptations that help them survive. One of these adaptations is the storage of bitter liquids in its vacuoles. Animals and insects avoid eating these awful-tasting plants, increasing the plants’ survival rates.

Hydrolytic enzymes in a plant’s central vacuole help control pathogens . The enzymes break down fungi and yeast cells which can harm the plant.

Vacuoles provide numerous functions for a plant. Without vacuoles, it would be difficult for a plant to survive.

Glossary

Vesicle: a small fluid-filled bladder, sac, cyst, or vacuole within the body

Eukaryotic: any cell or organism that has a clearly-defined nucleus

Organelles: small structures in a cell that are surrounded by membranes and have specific functions

Tonoplast: a semipermeable membrane surrounding a vacuole in a plant cell

Pathogens: organisms causing disease to their host

Central vacuole: a large vacuole found inside of plant cells

Turgor pressure: pressure exerted by fluid in a cell that presses the cell membrane against the cell wall

Osmosis: the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell’s partially permeable membrane

Selectively-permeable membrane: a membrane that allows only some substances and molecules to pass into or out of the cell

Concentration: the amount of a substance, such as a salt, that is in a certain amount of tissue or liquid, such as blood. A substance becomes more concentrated when less water is present.

Pollinators: animals or insects that transfer pollen from plant to plant

Anthocyanins: a major class of red to blue flavonoid pigments that are extensively represented in plants

Adaptations: any heritable trait that helps an organism, such as a plant or animal, survive and reproduce in its environment

Hydrolytic enzymes: enzymes that break down protein, lipids, nucleic acids, carbohydrates, and fat molecules into their simplest units

Carbohydrates: a type of organic compound including sugars, starches, and cellulose

Cell wall: a stiff outer layer around a plant, bacteria, or fungal cell

References

Vacuoles (plants). https://bscb.org/learning-resources/softcell-e-learning/vacuole-plants/

Sheng-Xiu Li. Turgor Pressure. December 19, 2012. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/turgor-pressure

The Biology of the Plant Central Vacuole: Structures and Functions. October 24, 2018.

https://www.bioexplorer.net/central-vacuole.html/

Recalling Ways in Which Plants Can Store Minerals in Their Cells to Avoid Toxicity. https://www.nagwa.com/en/videos/803169642981/

Contributors

Lisa Endicott: Author

My passion for science is rooted in my love and curiosity for nature and animals. I have successfully taught biology, health and English as a Second Language classes for 27 years in Madison, Wisconsin. I earned degrees in Biology and Life Science education along with a Masters in reading education from the University of Wisconsin, La Crosse. I completed my English as a Second Language certificate at the University of Wisconsin, Madison. I find teaching most rewarding when students dig deeper into lessons to answer their own questions. I am excited to write for Smore Science to share the extraordinary world of science. Young women, you belong in STEM careers. We need your voices and your talents. Embrace risks and challenge yourselves.

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