Large organisms require a definite transport system. In most higher plants the transport system is made up to tube-like structures called xylem and phloem. These constitute a vascular system. It extends from the roots through the stem and into the leaves. In the leaves they are clearly seen as a pattern of veins.
Water and minerals are transported from the roots upwards through xylem tubes. Phloem transports synthesized food from the leaves to the rest of the plant body. Transport in plants is also called translocation. The medium of transport in plants is water, while blood acts as a carrier of materials in the higher animals.