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Dicot and Monocot Root Differences in Biology Import Concepts Must to Know

Question. Difference Between Dicot and Monocot Root.

Answer:

Monocot Root:

A monocot root shows distinct regions. We will discuss each of them in the following. The components of the monocot root system are described below.

Illustration: Dicot and Monocot Root Differences in Biology Import Concepts Must to Know

Epiblema:

This is the single outermost layer of the root made entirely from parenchymatous cells and does not have any intercellular space. It bears unicellular epidermal root hairs with less cutin and more cuticles. This region of the monocot root is also known as rhizodermis.

Cortex:

It is made up of multi-layered oval parenchymatous cells and has intercellular spaces. These spaces help in the gas exchange and storage of starch. In monocots, a few layers of cortex below the epiblema give rise to a layer called exodermis which is made from multi-layered cuticularized sclerenchyma cells.

Endodermis:

It is the innermost layer of the cortex made of barrel-shaped parenchyma. It shows a ring-like formation around the stele and the cells are characterized by Casparian stripes. Due to the presence of Casparian stripes, endodermis forms a water-tight jacket around the vascular tissue, therefore it is also called a biological barrier. Endodermis regulates both the inward and outward flow of water and minerals and prevents the diffusion of air into xylem elements.

Pericycle:

It is made from thin-walled parenchymatous cells and is the outermost layer of the stellar system. The cells can become Sclerenchymatous in older roots. Numerous lateral roots arise from this layer.

Vascular Bundle:

The xylem and phloem systems are found in different radii alternating with each other in this region. The numbers of these systems vary from 8 - 46. The protoxylem lies towards the periphery whilst the metaxylem lies towards the centre. The protoxylem has spiral thickening and the metaxylem has pitted thickening. The phloem consists of sieve tubes, phloem parenchyma, and companion cells. The region functions as a transportation system of elements within the plant body.

Conjunctive Tissue:

It is made of parenchymatous tissue and separates the xylem and phloem system.

Pith:

It is a large well-developed part of the monocot root and is made up of thinly walled parenchymatous tissue. It contains high amounts of starch grains.

Dicot Root:

The following are the distinguishing features of the dicot root system. The five distinct regions are as same as the monocot root system which are described below.

Illustration: Dicot and Monocot Root Differences in Biology Import Concepts Must to Know

Epiblema:

It is uniseriate, colourless, thin-walled, and without intercellular spaces. The epiblema produces unicellular root hairs. Stomata and cuticle are absent.

Cortex:

It is thin-walled and made from polygonal or circular parenchymatous cells that usually have intercellular spaces. It is responsible for the transportation of salts and water from root hairs to the centre of the root.

Endodermis:

It is made of barrel-shaped compact parenchymatous cells and gas both passage cells and Casparian stripes. This region allows the radial diffusion of water and minerals through the endodermis.

Pericycle:

It is composed of a uniseriate layer of parenchymatous cells without intercellular spaces. Lateral meristem and lateral roots grow from the Pericycle region.

Vascular Region

The bundles are radial. The xylem system consists of tracheids, vessels, xylem fibers and xylem parenchyma. The phloem system consists of sieve tubes, phloem parenchyma and companion cells, Phloem fibers are absent or reduced.

Pith:

It is centrally located and is very small and is made of polygonal parenchymatous cells. It functions as a storage unit of food.

Table of Difference between Dicot and Monocot RootTable of Difference between Dicot and Monocot Root
Differentiating PropertyDicot RootMonocot Root
DefinitionMonocotyledonous roots are fibrous or adventitious roots consisting of a wide network of thin roots and root fibers that originate from the stem.Dicotyledonous roots are taproots consisting of a single primary root from which secondary and tertiary roots develop and grow vertically downwards through the soil.
Root systemMonocot plants have a fibrous or adventitious root system.Dicot plants have a tap root system.
Primary rootThe development of the primary root stops during the postembryonic development of the roots.The primary root continues to grow throughout the life of the plant in the form of the taproot.
Epidermal coveringThe monocot roots are covered by a cork cambium after the peeling of the epidermis.The dicot roots are covered by exodermis which is a modified epidermis.
CortexThe cortex in monocot roots is wide.

The cortex in monocot roots is composed of only parenchymatous cells.

The cortex in dicot roots is narrow.

The cortex of dicot roots is composed of both parenchymatous and Sclerenchymatous cells.

EndodermisThe endodermis of monocot roots is thicker.

Casparian strips are less prominent in monocot roots as these are only observed in young cells.

The endodermis of dicot roots is less thick.

Casparian strips are more prominent in dicot roots.

Passage cellsPassage cells are found in the endodermis of monocot roots.Passage cells are absent in the endodermis of dicot roots.
PericycleThe pericycle of monocot roots only forms the lateral roots.

The pericycle of monocots can either be single-layered or double-layered.

Pericycle of dicot roots forms the cork cambium and the lateral roots.

The pericycle of dicots is always single layered.

CambiumBoth cork cambium and vascular cambium are absent in monocot roots.Both cork cambium and vascular cambium are found in dicot roots.
Vascular bundlesThe number of vascular bundles is greater than six (polyarch) .

Xylem parenchyma is present.

The number of vascular bundles is usually between two and six (diarch to hexarch) .

Xylem parenchyma is absent.

Conjunctive tissueThe conjunctive tissue of monocot roots is parenchymatous.The conjunctive tissue of dicot roots is both parenchymatous and Sclerenchymatous.
PithThe pith in monocot roots is developed and prominent.The pith in dicot roots is less developed or reduced.
Secondary growthSecondary growth is absent.Secondary growth takes place to support vascular cambium and cork.
CoveringOlder roots are covered by a Cork.Older roots are covered by an Exodermis.
ExamplesPea, beans, peanuts, etc.Maize, banana, palm, etc.