Definition of Transpiration
Transpiration is the process by which water moves through a plant and evaporates from its aerial parts, such as leaves, stems, and flowers. It is a necessary process for plants, as water is necessary for photosynthesis, and transpiration enables mass flow of mineral nutrients and water from roots to shoots. Transpiration occurs through the stomatal apertures, and can be thought of as a necessary "cost" associated with the opening of the stomata to allow the diffusion of carbon dioxide gas from the air for photosynthesis.
Process of Transpiration
Transpiration refers to the evaporation and loss of water from the leafs surface, but it also explains how water moves through the rest of the plant in the xylem. When water is lost from the leaves surface, negative pressure forces water to move up the plant, often referred to as the transpiration pull. This allows water to be transported up the plant with no additional energy required. This means that water transport in the plant through the xylem is a passive process.
Factors Affecting Transpiration
Different factors affecting the rate of transpiration are:
- Cellular Factors: The orientation of leaf, the water status of the plant, structural peculiarities of the leaf, total number and distribution of stomata in a leaf.
- Environmental Factors: Light, humidity, temperature, atmospheric pressure.
Significance of Transpiration in Plants
The significance of transpiration is explained below:
- Transpiration helps in the conduction of water and minerals to different parts of the plants.
- Due to the continuous elimination of water from the plant body, there is a balance of water maintained within the plant.
- It maintains osmosis and keeps the cells rigid.
- A suction force is created by transpiration that helps in the upward movement of water in the plants.
- Transpiration helps balance the amount of water in the plants and keeps them cool.
In conclusion, transpiration is a crucial process for plants, as it enables the movement of water and minerals throughout the plant and helps maintain a balance of water within the plant.
