Transpiration is the process by which water leaves a plant. Water intake from the soil by plant root will ultimately lost to the atmosphere, through the stomata in the leaves. The stomata are bordered by guard cells that open and close the pore. The opening of the stomata to allow the gaseous exchange for photosynthesis, it also allows the loss of water from plant.
In transpiration process, the air passes across the leaves and evaporate some water out the stomata. The loss of water from the leaves creates a negative pressure, so water is draw up the stem via xylem. So, new water enters the plant through the root to replace the water moving up the stem. Thus, enables mineral nutrients and water enter the plant. The rate of transpiration can be affect by several factors, such as humidity levels, light intensity, temperature.
In this experiment, we are investigating the effect of light, wind, and their combine effect on transpiration rate. In part 1, we measure the transpiration under ambient laboratory condition. The effect of wind and light on transpiration is investigated in part 2 and 3 respectively. In part 4 we measure the combine effect on transpiration by opening the fan and shine light onto the plant. The negative pressure creates by transpiration is measured by a pressure sensor. Below is a simple diagram showing the process of transpiration.
The absolute gradient of the graph indicates the rate of transpiration. Form the result the slope is greatest in experiment 4, smallest at experiment 1. The transpiration rate is slowest at ambient condition. Increase in light intensity can increase the transpiration rate. Increase in wind speed also increase the transpiration rate. The transpiration rate is greatest when combining the two factors.
The increase in wind speed increase transpiration rate, it is because water lost from transpiration is often left in a residual layer just beneath the leaf. If left alone, this can reduce...