Rate of Transpiration Calculator
Calculation Results:
Total Rate of Transpiration: units/min
Specific Transpiration Rate: units/min/cm²
Understanding the Rate of Transpiration
Transpiration is the biological process where water is lost from a plant in the form of water vapor, primarily through the stomata on leaf surfaces. Measuring the rate of transpiration is essential for plant physiologists, agronomists, and students to understand plant health, water efficiency, and the impact of environmental conditions.
The Calculation Formula
The basic formula used by this calculator to determine the rate of water loss is:
If you include the leaf surface area, we calculate the Specific Transpiration Rate (Flux):
Factors Affecting Transpiration Rates
- Light Intensity: Higher light typically increases the rate as stomata open wider for photosynthesis.
- Temperature: Increased heat speeds up evaporation and reduces relative humidity, driving water out of the leaf faster.
- Humidity: Higher external humidity decreases the concentration gradient, slowing down transpiration.
- Wind Speed: Wind removes the "boundary layer" of water vapor near the leaf surface, significantly increasing the rate.
Practical Example
Suppose you are using a potometer to measure a geranium plant. Over a period of 20 minutes, you observe the air bubble move a distance corresponding to 4.0 ml of water. The total surface area of the leaves is 80 cm².
- Total Rate: 4.0 ml / 20 min = 0.2 ml/min
- Specific Rate: 0.2 ml/min / 80 cm² = 0.0025 ml/min/cm²