2019-03-01 Biology Times

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Biology Times (^19)
Tyloses are found in secondary xylem and rarely in primary xylem. During the formation of tyloses the
pit membranes of the half bordered pit pairs, present between a parenchyma cell and a vessel, enlarge and
form a bladder like structure, as a result the lumen is almost blocked. The nucleus of the wood parenchyma
together with its cytoplasm passes into the tylose. In fully formed tyloses, starch grains, resins and gums
are formed. In each cell, there may be one to many tyloses. Normally tyloses develop in the heart wood of
flowering plants adding to the durability of the wood
Heart wood is used as timbers and is of commercial importance. The study of timbers is called sylviculture.
The heartwood is resistant to termites and microorganisms. It is used for the preparation of furnitures,
doors, windows etc.
Differences between Sapwood and Heart wood

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