Protein Extraction from Xylem and Phloem Sap

It is well known that phloem and xylem vessels transport small nutrient molecules over long distances in higher plants. The finding that proteins also occur in both transport fluids was unexpected, and the function of most of these proteins is not yet well understood. This chapter outlines how proteins can be obtained and purified from xylem and phloem saps to perform subsequent proteomic analyses.