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Draw a well-labeled diagram of T.S. of monocot root?

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Internal Structure of Orchid Root: Most orchids are epiphytes. They have hanging aerial roots. Their anatomy is different from other monocotyledonous roots and is as follows:

1. Velamen:

  • It is the outermost tissue of the root.
  • The cells of this tissue are large, closely packed, with fibrous thickenings.
  • These are dead cells. These cells are filled with air in dry season and during rains these cells absorb water.
  • Velamen is like a multilayered epiblema.
  • The outermost layer of velamen is called limiting layer. It is cuticularized.

2. Exodermis:

  • It is the outermost layer of the cortex.
  • The lateral walls of the exodermal cells are thickened.
  • Passage cells are found here and there.

3. Cortex:

  • The cortex is made up of thin walled parenchymatous cells.
  • The innermost layer of the cortex is endodermis.
  • All tissues enclosed by the endodermis are called stele.

4. Pericycle:

  • It is one layered tissue on the inner side of endodermis.

5. Conjunctive tissue:

  • It is the parenchymatous tissue surrounding and in between the vascular bundles.

6. Vascular bundles:

  • Vascular bundle are radial. Xylem and phloem are present as alternate patches and are situated in a ring.
  • Vascular bundles are more than six. Xylem is exarch.

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