Tylosis
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Related to Tylosis: tylosis palmaris et plantaris
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
Tylosis
a blister-like protrusion of xylem parenchymal cells that obstruct the vessels or, less commonly, the tracheids. Tyloses form when the closing membrane of a pit grows into the lumen of a vessel. The cytoplasm and, sometimes, the nucleus of the cell move into the protrusion, which is not separated by a septum from the mother cell. Tyloses may be filled with starch, calcium salts, resin, or gum. Although they are most characteristic of woody plants, they also occur in herbaceous plants, such as pumpkin, purslane, and dock. Tyloses lower the water-retaining capacity of the heartwood and increase resistance to rotting and penetration by fungi. The formation of tyloses is sometimes a response to injury.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.