Explanation

Generally, it is considered that inorganic nutrients are transported by xylem, while phloem takes part in transporting organic nutrient. But same is not true. In xylem sap, nitrogen is also transported as ions, organic form of amino acids etc. So, there is an exchange of even a small amount of material between xylem and phloem. A majority of minerals enter into the root through active absorption as concentration of minerals are more in roots interior then in soil. Relationship between the source and sink is variable and depends upon the season and need of plants