The roles of water

Water is used for many things in the life of a plant such as: 

• It keeps the plant upright and enables the leaves to be held in the best position for sunlight to reach them.
• Nutrients and trace elements are carried in solution to the cells of the plant where they are used for growth and activity.
• Water allows plants to cool themselves by evaporation through the stomata.
• It is also needed for photosynthesis
• Water helps the upward movement of salts and nutrients in the plant. 
• Water provides the transport system for important substances from the one part of the plant to another (translocation)

Photosynthesis

Photosynthesis is a biochemical process in which plants, algae, and some bacteria harness the energy of light to produce food. Ultimately, nearly all living things depend on energy produced from photosynthesis for their nourishment, making it vital to life on Earth. It is also responsible for producing the oxygen that makes up a large portion of the Earth's atmosphere. Organisms that produce energy through photosynthesis are called phototrophs.

Stoma

A tiny pore in a plant leaf surrounded by a pair of guard cells that regulate its opening and closure, and serves as the site for gas exchange.

Stomata is the plural of Stoma