Internal structure of Monocot root

MONOCOT ROOT

Monocot root lacks of secondary growth and shows following internal structures:

1.EPIDERMIS : it is composed of a thin walled,compactly arranged single layer of parenchymatous cells without intercellular space.it also gives rise to unicellular root hair.cuticle and stomata are absent in monocot root. epidermal cells and root hair take part in absorption of water and minerals from soil. multilayer epidermis is found in epiphytic plants like orchid and is called as velamen.pnematodes of velamen help in gaseous exchange.

2. CORTEX: it consist of layers of parenchymatous cells having intercellular spaces. cells are oval in shape and help in gaseous exchange.they help in starch storage too. in maize,outer layer of cortex changes into exodermis or hypodermis. exodermis is protrctive in nature.

3. ENDODERMIS: endodermis isthe innermost layer of cortex.it consists of single layer of closely packed barrel shaped parenchymatous cells. the cells are characterised by the presence of casprian strips in their radial walls.they are formed by the deposition of suberin and lignin.endodermis opposite to protoxylem are thin walled and are called as passage cells. it allows the radial diffusion of water.

4. PERICYCLE:it lies below the endodermis and forms the outer boundery of primary vascular tissue.it is usually single layered and sometimes multilayered.it may be parenchymatous or sclerenchymatous . it gives rise to lateral roots.

5.VASCULiAR BUNDLE: the vascular bundles are of radial type.xylem and phloem are radially arranged alternating with each other .they are 8-20 in number.xylem shows exarch condition.metaxylem vessels are larger with spherical and pitted thickening.protoxylem have smaller vessels and with annular thickenings. Phloem contains all component except bast fibre.xylem help in conduction of water and minerals while phloem helps in conduction of food materials.

6. CONJUNCTIVE TISSUE: found between xylem and phloem bundles.maybe parenchymatous or sclerenchymatous.

7. PITH: It is central part of root and lies internal to vascular bundle.it is made up of thin walled parenchymatous cells with intercellular space.it  is well developed in monocot root.