Question

Describe the Primary structure of T.S of Monocot stem.

Answer 1

(i) Epidermis:

• Outer most layer of monocot stem.
• Made up of single layer and tightly packed parenchyma cells.
• Outer wall is covered by thick cuticle.
• Few stomata are seen in epidermis. 
• Multicellular hairs are absent

(ii) Hvpodermis:

• The layer below the epidermis is called hypodermis.
• Hypodermis is made up of sclerenchymatous cells.
• It is interrupted by chlorenchyma.

Sclerenchyma provides mechanical support to plant.

(iii) Ground tissue:

• There is no distinction of cortex, endodermis, pericycle and pith.
• Inner to hypodermis parenchyma cell forms the ground tissue.

(iv) Vascular bundles:

• Vascular bundles are scattered in the ground tissue. Each vascular bundle are surrounded by bundle sheath by sclerenchymatous tissue.
• Vascular bundles are conjoint, collateral, endarch and closed.
• Xylem contains meta xylem and protoxylem.
• In mature Vascular bundle the lowest protoxylem disintegrates and form a cavity called protoxylem lacuna.
• Phloem contains seive tubes and companion cells.

(v) Pith:

• It is not differentiated in monocot stem.