"sieve-tube element." YourDictionary, n.d. Web. 14 July 2019. <https://www.yourdictionary.com/sieve-tube-element>.
sieve-tube element. (n.d.). Retrieved July 14th, 2019, from https://www.yourdictionary.com/sieve-tube-element
An elongated, food-conducting cell in phloem in angiosperms. Unlike the tracheary elements of xylem, sieve elements have living protoplasts when mature, but they lack a nucleus and are dependent upon companion cells for certain functions. At the ends of each sieve-tube element are sieve plates, areas of the cell wall containing numerous large pores. The sieve-tube elements are aligned end to end and form continuous tubes, along which nutrients flow relatively unimpeded from cell to cell through the sieve plates. Sieve-tube elements are more specialized than the sieve cells found in gymnosperms.