What is a defining feature of phloem sap?
A second vascular tissue is specialized to transport sugars throughout the plant using a different mechanism. Like the water-carrying xylem, the food-carrying phloem (Figure here) consists of elongated cells arranged end-to-end. However, phloem cells are living, and their ends are connected with both sieve plates and many tiny bridges called plasmodesmata. To move sap – solutions of sugars which the plant has photosynthesized – plants create and harness diffusion gradients.