Water is the major constituent of any living organism. A plant with optimum water content is a very important part a plants growth and development. It is possible that more plants die through a lack of water than any other cause.
FUNCTIONS OF WATER.
A plant is made up of about 95% water, this being the main part of all living matter. When a plant cell is full with water or turgid, the resulting pressure of the water within the membrane or vacuole acts as a support for the cell and therefore the whole plant. This means that a plant that is losing more water than it is absorbing therefore causing the plant to collapse and wilt. In the case of aquatic plants they have very little internal support tissue and are supported by external water pressure. In order to survive, any organism must carry out a complex and chemical reaction. Raw materials for chemical reaction must be transported and brought into contact with each other through a medium, an ideal medium is water. Water is also used as one of the raw materials in photosynthesis, which is one of the most important processes in a plants development and growth.
MOVEMENT IN WATER.
Water moves though a plant starting with the root passing into the stem then into the leaves and on into the atmosphere the process of water loss through the leaves is called diffusion whereby the molecules of gases or liquids move from an area of high concentration to another area of relatively low concentration. In the case of plants this means that water moves through the stomata from inside the leaf, which is an area of high concentration into the atmosphere immediately surrounding it, which is an area relatively low concentration of water or humidity. Thus the pathway of water through a plant is described as three distinct stages; water uptake; movement up the stem; and transpirational loss through the leaves.
1 Water Uptake.
The uptake of water through the roots by a special form of diffusion is called osmosis.