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How Photosynthesis Is Affected by the Amount of Water

By Puriry Makandi ; Updated September 21, 2017
Water is needed for photosynthesis to take place.

Photosynthesis is the biochemical process by which plants produce food for growth through the use of light and water. Carbohydrates are derived from carbon dioxide and water during the process.

Electron Supply

During photosynthesis, water supplies electrons in green plants in the photolysis stage. For the process to succeed, an adequate supply of water has to be available to facilitate electron transfers.

Photosynthesis Rate

In reactions independent of light, water supply increases the concentration of carbon dioxide in carboxysomes. Carboxysomes are bacterial micro compartments that contain enzymes that aid in carbon fixation during photosynthesis. Water increases the rate of photosynthesis because the carboxysomes increase the concentration of carbon dioxide around the rubisco, an enzyme that catalyzes the initial part of carbon fixation process in photosynthesis.

Absorption of Carbon Dioxide

During the carbon fixation stage in photosynthesis, water helps in the absorption of carbon dioxide. This is carried out through the release of electrons in the oxidation process. Absorption of carbon dioxide increases the production of oxygen gas during the photosynthesis process.

Carbon Dioxide

Carbon concentration in plants is regulated by water intake. When adequate supplies of water are absorbed, respiration through the stomata regulates carbon dioxide concentration.


High temperatures favor a higher water intake. However, if temperatures are low and the water supply is high, the humid conditions stifle photosynthesis because water cannot be expelled from the leaves.


An adequate water supply helps prevent plants from wilting. This preserves not only water levels but also plant pigment that is essential to photosynthesis.


About the Author


Based in Nairobi, Kenya, Puriry Makandi has been writing since 2008. She works as a writer for Kitabu Publishers, where she writes features and news articles, among other assignments. She holds a Bachelor of Arts in literature from Egerton University.