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Xylem water transpor
For 330 Xylem water transport, many from Taiz & Zeiger 2002
Term | Definition |
---|---|
Cavitation | Breakage of water columns under tension in the xylem. |
Embolism | Bubble formation that expands within the xylem water column under tension. |
Perforation plate | Perforated end walls at each end of vessel elements. |
Pit membrane | The porous layer between pit pairs containing primary cell walls that allow water movement between tracheids. |
Pit pair | Formed by opposing pits of adjoining tracheids. |
Primary cell walls | A rigid, protective cellulosic layer surrounding the plasma membrane of plant cells, which makes up the appoplast and permits cell growth. |
Secondary cell walls | The thickened cell wall laid down between the primary cell wall and the plasma membrane consisting largely of cellulose imbedded in lignin that adds strength for upright growth and is impermeable to water. |
Torus | A central thickening of pit membranes in tracheids of some species of conifers that acts like a valve to close the pit. |
Tracheids | Elongated, spindle-shaped cells arranged in overlapping vertical files that are present in both angiosperms and gymnosperms and function in xylem water transport. |
Vessel elements | Short and wide vessel members with perforated end walls that function in angiosperm xylem water transport. |
Xylem | Water-conducting tissue of plants. |
Xylem elements | The conducting cells in the xylem of which there are two important types: tracheids and vessel elements; also called tracheary elements |