Exudates of xylem and phloem have been studied. The xylem sap mainly contains inorganic compounds. Most of the Sulphur and Potassium are in the form of inorganic compound. However. most of the nitrogen is in the form of organic compound. In case of phloem sap also: both organic and inorganic compounds are found. Organic compounds are more in phloem sap because it carries the food. But it also has inorganic compound because exchange of materials takes place between phloem and xylem.