Aarti Gupta
Last Activity: 10 Years ago
In gymnosperms and dicotyledons,secondary growth occurs in the stem and root.The secondary protective tissue -the periderm replaces the epidermis.Unlike epidermis,periderm is an multilayered tissue system and consist of Phellogen(cork cmbium) or lateral meristem which produces-
1.Phellem(cork) towards outside and
2.Phelloderm(secondary cortex) towards inside.
The bulk of periderm constitutes cork.The cells of cork are dead at maturity with thick walls impregnated with a waxy material called suberin.Commercial cork is harvested from oak tree(Quercus suber).
Two features of cork-
1.Cork is highly compressible and does not catches fire easily.
2.Cork insulates trees from freezing temperatures in the cold winter and also helps in conservation of water.