Transpiration was first measured by Stephen Hales. A Potometer is used to measure transpiration.
Generally, plants send out excessive amounts of water vapour through stomata, lenticels, and cuticles.
Evaporation of water molecules from the leaf cells creates a suction that pulls water from the xylem cells of roots.
The process of transpiration helps in the absorption and upward movement of water and minerals from the root to the leaves.
Transpiration regulates the temperature of plants and helps in cooling.
Mechanism of Transpiration
In normal conditions, stomata are closed in the absence of sunlight
But they open in the presence of light. Potassium ions are involved in this process.
Factors Affecting the Process of Transpiration: Temperature, atmospheric moisture, wind, velocity, solar radiation and soil environment affect the process of transpiration.