Secondary Growth in Dicot stem

  • The growth in thickness by the activity of secondary tissues is called secondary thickening
Stelar secondary growth by vascular cambium
  • Formation of cambial ring
  • Fascicular cambium( cambium between xylem and phloem) and interfascicular
  • cambium join to form a continuous vascular cambial ring
  • The cambium produces secondary phloem to the outside and secondary xylem to the inside.
  • More secondary xylem is produced due to more activity of vascular cambium to the outside.
Extra stelar Secondary growth or Periderm formation by cork cambium
  • The formation of more and more secondary tissues exerts a pressure on cortex and epidermis
  • The epidermis gets ruptured and is replaced by another protective tissue developed in the
  • cortex from the cork cambium is the periderm. Periderm consists of meristem called phellogen or cork cambium. Cork cambium produces cork or phellum to the outside and phelloderm or secondary cortex to the outside. Periderm has specialized openings called lenticels on its surface for gaseous exchange
secondary Growth in a Typical Dicotyledonous Stem - Copy
Important points
  • Secondary vascular tissues are present
  • Formation of cambial ring
  • Fascicular cambium (cambium between xylem and phloem) and interfascicular
  • cambium join to form a continuous circular vascular cambial ring
  • The cambium is partly primary and partly secondary
  • The cambium produces secondary phloem to the outside and secondary xylem to the inside.
  • Cork cambium is present and produces cork to the outside and secondary cortex to the inside forming periderm.
  • Primary vascular bundles are limited in number
  • Vascular bundles conjoint, collateral and open
  • xylem is endarch
Common material: Eupatorium
Read more: Difference between Secondary Growth in Dicot stem and Dicot Root
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