xylem vessels

[moo]

how are xylem vessels dead? surely they were alive once? i asked my science teacher who replied "because they are" which wasn't quite a good enough explaination... how did dead cells just appear from nowhere???? confused!!

[dinsdale]

as stated in "how it works" they were not always dead, xylem vessles die once they hit maturity, to form a strong,none living passage for the flow of water. http://en.wikipedia.org/wiki/Xylem_vessel_element