Describe : Transpiration Pull.

Explanation

In higher plants, the flow of water upward through the xylem in plants can achieve fairly high rates up to 15 metres per hour.
In this either water is pushed or pulled through the plant. Most researchers agree that water is mainly pulled through the plant. and that the driving force for this process is transpiration from the leaves.
This is referred to as the cohesion-tension-transpiration pull model of water transport.
Water is transient in plants. Less than 1 percent of the water reaching the leaves is used in photosynthesis and plant growth. Most of it is lost through the stomata in the leaves. This water loss is known as transpiration.
By enclosing a healthy plant in polythene bag and observing the droplets of water formed inside the bag.
You could also know water loss from a leaf using cobalt chloride paper, which turns colour on absorbing water.