Plants have a transport system, in some ways similar to an animal's blood circulatory system. However, it is rather different in several important ways. For example, there is no pump like the heart, no circulating cells and liquids do not continuously move round and round.
The substances which are transported - mineral salts (ions) from the soil, and the products of photosynthesis from the leaves - are dissolved in water (as an "aqueous solution"). The transport system basically consists of 2 types of conducting tissue, each of which is made from cells which have been modified for their special purpose. Some cells die as a result of this modification, and they may also lose some of their internal components.
When you look at sections of plant material, you will see this tissue as a mass of cells, rather than easily defined tubes like blood vessels in animals!
Water and mineral salts enter a plant through special cells called root hair cells. The water is taken up by a special form of diffusion called osmosis , but the mineral salts (ions) may also be taken up by active transport which uses some of the plant's energy to concentrate them.
Xylem vessels carry water and minerals on into the plant, but only in an upward direction. These vessels form a continuous "pipe" from the root to the stem and leaves.
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