Primary dicot stem - Characteristics features of primary dicot stems are-
* Epidermis is present at the outer most part of the stem which is made up of rectangular barrel shaped cells.
* It has distinct cuticle, multicellular cutinised hair called trichomes and stomata at places.
* Stomata contains kidney shaped guard cell.
* From inner layer to the epidermis is called hypodermis which is made up of collenchymatous cell.
* Hypodermis is followed by parenchymatous cortex.
* Endodermis are known as starch sheath.
* Endodermis is without cadparian strips.
* Pericycle is situated just behind the endodermis.
* Sclerenchymatous pericycle occurs as bundle caps.
* Vascular bundles lie in a ring which is called eustele.
* They are wedge shaped, conjoint, collateral and open.
* Xylem is end arch means centrifugal which having radial rows of angular vessels where tracheids fibre and parenchyma cell is present in between and around them.
* A strip of fascicular cambium occurs between the xylem and phloem that helps in secondary growth.
* Secondary growth pushes the primary xylem and primary phloem away from each other.
* In between the vascular bundles medullary rays are present and they lie radially elongated parenchyma cells.
* The pith lies in the center.
Monocot Stem -
Characteristics features of monocot stem are -
* The stem is covered by epidermis. It is rectangular barrel shaped and silica is deposited on the outer surface of the stem causes stiffness and provide protection to the stem.
* A layer of cuticle is present.
* In some places stomata is present and they have dumb bell shaped guard cells.
* Hypodermis contain 2-3 layered , sclerenchymatous and ground tissue is undifferentiated.
* Endodermis , pericycle,pith are not recognisable.
* Ground tissue consists of parenchyma cells which store food.
* Vascular bundles are numerous and possesses atactostele.
* Vascular bundles are oval in shape and surrounded by sclerenchymatous cell which is called fibrovascular bundles.
* Type of each vascular bundles is collateral,conjoint and closed.
* As phloem lies outside the xylem is called endarch.
* Protoxylem has a schizo lysigenous cavity which is called protoxylem cavity.
* Metaxylem has two lateral rounded vessels where protoxylem has 1-3 small oval vessels.
* Tracheids are observed between.
Primary Dicot Root – Characteristics features of dicot roots are –
* Outside the root is covered by an layer called epiblema or piliferous layer (uncutinised thin layer rivalled rectangular cells).
* Some of the cells of this piliferous layer form thin layer tubular out growths called root hairs.
* These are specialized for water absorption from soil interspaces.
* Other epiblema cells can also absorbed water and minerals from the soils.
* In the other part of the monocot plant the root hair shrivel and epiblema converted to thick walled.
* Epiblema have several layers of thick cortex.
* Cortex is followed by endodermis (a layer which is compactly arranged by barrel shaped cells that possess ligno- Siberian thickenings which are called cadparian strips.
* Endodermis function as check post as where one or more layer of pericycle lies below endodermis.
* Pericycle gives rise to lateral roots which is the part of the vascular cambium and whole of cork cambium.
* Vascular bundles consists ofalternate, radial bundles (2-8) of xylem and phloem.
* Xylem is exarch or centripetal means protoxylem is situated outside.
* Pith may be present or absent. If the pith is absent or small metaxylem of different bundles meet at the center.
* Depending upon the number of xylem present root can be diarch ,triarch, tetrarch etc.
* Xylem is made up of polygonal vessels, where the protoxylem vessels being narrow and small in size.
* Phloem consists of sieve tubes, companion cells, phloem parenchyma and occasional phloem fibres.
* Conjunctive parenchyma occurs between xylem and phloem bundles and it secondarily form main part of the vascular cambium.
Monocot Root: Characteristics features of monocot roots are -
* Outer layer of the root is called epiblema or piliferous layer.
* The cells of this layer are oval rectangular ,thin walled and uncutinised.
* Some of the cells that give rise to tubular root hairs for the absorption of water from the soil interspaces.
* The area of the root which is comparatively older, the root hairs shrivel and epiblema cells either become thick walled or are shed.
* Cortex are several layers thick and is made up of parenchymatous cell.They make participation in storing food and conduct sap from outside.
* The outer layer and older part of the cortex thickened to form protective layers called exodermis.
* Endodermis is a single compact layer made up of barrel shaped cells. The young cell that possess ligno- suberised casparian thickenings. Whereas in older parts the endodermal cells become thick walled except it is opposite in protoxylem points. These cells are called passage cells.
* Pericycle is made up of one or more layer of parenchymatous cell.
* Pericycle gives rise to root branches where the older part of the cell wall become thickened.
* Pith cells store food and vascular strands occurs around a central pith.
* Vascular strand contains a large number of alternate radial bundles of xylem and phloem.
* Xylem is exarch and centripetal.
* Vascular strand is polyarch that is embedded in conjunctive tissue.
* Xylem contains oval rounded vessels.
* Phloem is made up of sieve tubes and companion cells and secondary growth is absent.
* Very rare species are there those are having vascular bundles less than 8.
Leaves of dicot plants - Characteristics features of leaves of dicot plants are –
* Upper layer of the leaf contains thick and lower layer contains thin cuticles.
* Intercellular space is bigger in leaf.
* leaves of dicot plants donot contain bulliformed cells.
* Number of stomata in both side of the leaves of plant in not equal ,it is more in lower surface of the leaves.
* Reticulate venation is observed in the leaves of dicot plant.
* Contains large and small vascular bundles.
Leaves of monocot plant- Characteristics features of leaves of monocot plants are
* Both layer of the leaf contains thin cuticles.
* The intercellular space between the cells are less.
* Leaves of monocot plants contains equal number of stomata in both side of the leaves.
* They have bulliformed cells in their leaves.
* Parallel venation is observed in monocot plant leaves.
* Monocot leaves have large vascular bundles.