Dicotyledonous Root

 

Epidermis

  • The outermost layer of a dicot root is called epiblema or piliferous layer.
  • It is made of a single layer of parenchyma cells.
  • The cells have tubular outgrowths called root hairs.
  • Cuticle and stomata are absent.

Cortex

  • it is the region between epidermis and endodermis.
  • It is homogeneous and is composed of loosely arranged parenchyma cells.

Endodermis

  • It is the innermost layer of cortex.
  • It is composed of a single layer of barrel-shaped cells.
  • The radial walls of the cells have casparian strips due to the deposition of suberin.

Stele

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  • Stele is the central part of the root.
  • It is very small when compared to the size of the cortex.
  • It is composed of the vascular tissue and the intrastelar ground tissue.
  • Pericycle is the outermost layer of stele.
  • It is composed of a single layer of parenchymatous cells.
  • Growth of lateral roots and vascular cambium during secondary growths takes place in these cells.
  • Pith is very small and inconspicuous.
  • Vascular bundles are seen in the central position.
  • They have radial arrangement. It is a characteristic feature of roots.
  • Protoxylem is seen towards the periphery, and metaxylem towards the centre. Hence, the xylem is exarch. This is also a characteristic feature of roots.
  • The parenchymatous cells found between the xylem and phloem is known as conjective tissue.

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