The parts of the plant which are seen under the soil are called the roots. They absorb water and minerals from the soil and fix the plant firmly to the soil. Monocot roots are fibrous roots. The radicle gives rise to the main root soon replaced by a cluster of roots from the base. The transverse section of monocot root shows three distinct region-piliferous layer, cortex and stele.
Piliferous layer: It is the outermost layer, made up of single layered thin walled living cells. The stomata and cuticle are absent.
Cortex: Immediately beneath the epidermis is a massive cortex lies consisting of thin walled parenchyma cells having sufficiently developed intercellular spaces among them. The sclerenchyma cells are commonly found in the cortex of monocotyledons. The inner most layer of the cortex is the endodermis which is composed of barrel shaped compact cells having no intercellular spaces among them. The endodermal cells possess casparian strips on their anticlinal walls. The cells opposite to protoxylem cells remain thin walled without casparian thickenings and are called passage cells. The passage cells allow the passage of water from the cortical cells to the xylem.
Stele: The stele consists of pericycle, vascular tissues, conjunctive tissue and pith.
The pericycle is single layered and parenchymatous.The cells in the pericycle contain abundant protoplasm. The lateral roots are originated from the pericycle.
Vascular tissues are xylem and phloem. In monocot root the xylem and phloem occur as separate bundles. The xylem and phloem bundles are equal in number. They are arranged on different radii. Such an arrangement of vascular tissue is called radial. The xylem bundle consists of protoxylem and metaxylem.Protoxylem lies towards the periphery and metaxylem towards the centre.This condition is called exarch. The number of xylem vessels in each bundle is limited. The conjunctive tissue and pith are seen. The pith is parenchymatous and, large and well developed.