What is the difference between xylem and phloem?

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Both xylem and phloem are vascular tissues found in a plant. Xylem is a tubular structure which is responsible for water transport from the roots towards all of the parts of the plant. Phloem is also a tubular structure but is responsible for the transportation of food and other nutrients needed by plant. Xylem imports water and minerals while Phloem transports water and food. Xylem exists as non-living tissue at maturity, but phloem is living cells.

Xylem: Hard wall cells transport water and mineral nutrients
Phloem: Relatively soft -walled cells transport organic nutrients

"Hardness and softness" is a function of the amount of lignification and extractive content of the individual cell walls not there location in the tree.

Xylem:

1. It is a dead complex permanent tissue. Sapwood is xylem and mostly alive
   
2. It is the principal water conducting tissue of vascular plants.
3. Xylem consists of tracheids , vessels , xylem parenchyma and xylem fibres. Also ray parenchyma Also the xylem of softwoods (Gymnospermae) do NOT contain vessels.
   

Phloem:

1. It is a living complex permanent tissue. Inner phloem is alive. Outer phloem is dead.
   
2. It is the principal food conducting tissue found in vascular plants. Actually only the first .2-.7mm of the phloem is functional in food transport. The rest is non-functioning (ref. Esau's Plant Anatomy, 3rd ed. 2006, Chap.14) also (ALFIERI, F. J., and R. F. EVERT. 1968. Seasonal development of the secondary phloem in Pinus. Am. J. Bot. 55, 518-528.)
   
3. It consists of sieve cells , sieve tube elements , phloem parenchyma and phloem fibres. There are also phloem ray cells.
   

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Xylem consists of the inner heartwood (the dead part) and the outer portion called the sapwood (the mostly living part.) Xylem "wood" from the Greek xylon. The actual transport of the water and minerals from the roots (sap) is carried out by the outer portion of the sapwood (nearest the bark).The largest percentage of the sap is transported in the first few growth rings.


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First answer by Natural Val. Last edit by Phloem. Contributor trust: 6 [recommend contributorrecommended]. Question popularity: 67 [recommend question].