an elongated cell whose walls contain perforations (sieve pores) that are arranged in circumscribed areas (sieve plates) and that afford communication with similar adjacent cells.
An elongated, food-conducting cell in phloem characteristic of gymnosperms. Sieve cells have pores through which nutrients flow from cell to cell, but they have no sieve plates like the more specialized sieve-tube elements of angiosperms. Compare sieve-tube element.
noun 1. Eduard [ey-doo-ahrt] /ˈeɪ du ɑrt/ (Show IPA), 1850–1932, German philologist.
noun, Physics. 1. the standard unit in the International System of Units (SI) of dose equivalent having the same biological effect as one joule of x-rays per kilogram of recipient mass (or one gray): The average person receives about 2 to 3 one-thousandths of a sievert per year from naturally occurring radiation in the environment. […]
noun, Botany. 1. a vertical series of sieve cells in the phloem, specialized for the conduction of food materials. 2. a single sieve cell. noun 1. (botany) an element of phloem tissue consisting of a longitudinal row of thin-walled elongated cells with perforations in their connecting walls through which food materials pass
- Sieve-tube element
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 […]