I will try to provide more specific information in the near future. However, you will learn much by studying the information available at the present sites. I recommend that you review the links as you prepare for lab and as you write your reports on your observations. This first demonstration of transpiration consists of a potted Coleus plants that has roots, stems and leaves intact. One branch of the plant was inserted into a glass flask and the opening sealed with a cotton plug.
Transpiration is the loss of water vapor from the plant surface.
In the demonstration of the intact plant, there is no way to determine if the moisture that is transpired is being pushed up the plant by the root system, or if it is being pulled up the plant by the shoot system. In this demonstration, the shoot of a vigorous Coleus plant has been cut from the root system, and the cut stem is inserted into a container of water. Later, when you dissected the plant, you used the location of the red dye to mark the location of the xylem tissue that was transporting the eosin. Today, in a similar procedure you will allow eosin to move up the stems of an herbaceous and a woody stem. By noting the distance the dye travels in the stem in timed period, you will estimate the rate of transport of materials in the xylem.