Tracheid

Tracheid of oak shows pits along the walls. It has no perforation plates.

A tracheid is a long and tapered lignified cell in the xylem of vascular plants. It is a type of conductive cell called a tracheary element. Angiosperms use another type of conductive cell, called vessel elements, to transport water through the xylem. The main functions of tracheid cells are to transport water and inorganic salts, and to provide structural support for trees. There are often pits on the cell walls of tracheids, which allows for water flow between cells. Tracheids are dead at functional maturity and do not have a protoplast. The wood (softwood) of gymnosperms such as pines and other conifers is mainly composed of tracheids.[1] Tracheids are also the main conductive cells in the primary xylem of ferns.[2]

The tracheid was first named by the German botanist Carl Gustav Sanio in 1863, from the German Tracheide.[3]

  1. ^ Cuny, Henri E.; Rathgeber, Cyrille B. K.; Frank, David; Fonti, Patrick; Fournier, Meriem (2014). "Kinetics of tracheid development explain conifer tree-ring structure". New Phytologist. 203 (4): 1231–1241. doi:10.1111/nph.12871. ISSN 1469-8137. PMID 24890661. S2CID 22862428.
  2. ^ Pittermann, Jarmila; Limm, Emily; Rico, Christopher; Christman, Mairgareth A. (2011). "Structure–function constraints of tracheid-based xylem: a comparison of conifers and ferns". New Phytologist. 192 (2): 449–461. doi:10.1111/j.1469-8137.2011.03817.x. ISSN 1469-8137. PMID 21749396.
  3. ^ Sanio, C. (1863). "Vergleichende Untersuchungen über die Elementarorgane des Holzkörpers". Bot. Zeitung. 21: 85–91, 93–98, 101–111. ISSN 2509-5420.