Capillary action is part of the reason that water rises in a plant. The water enters the plant’s roots and moves to other parts of the plant through xylem (tiny tube-like structures).
Steps to be taken
Fill a plastic cup about one-fourth full with water. Add about ten drops of red food colouring and stir.
Select an inner stalk of celery. You want one that has pale green leaves.
Use scissors to cut across the end of the celery stalk. Observe and make note of the colour of the cut end of the celery stalk. Also make note of the colour of the leaves on this stalk.
Stand the celery stalk, cut end down, in the red water.
Observe the colour of the colour of the leaves on the celery stalk periodically for two or more days.
The pale green leaves will take on a reddish colour. Cut a cross section of the celery and you can see straw like tubes in the stalk that carry the water to the leaves, as they will all appear red.
How it happens?
This is because the red colouring dissolved in the water and moved with the water through the xylem tubes in the celery stalk and leaves the red colouring was deposited in the leaves, but most of the water evaporated through tiny opening in the leaves. The evaporation of the water from plants is called transpiration. This evaporation of the surface water from the xylem tubes results in more water being pulled into the roots to keep the xylem tubes filled. Thus, there is a continued movement of water through the plant. Nutrients in the soil that dissolve in water are transported to the cells in plants in a similar way that the red colouring was transported to the leaves of the celery.