Difference between Monocot and Dicot Stem

By Jaxson

Main Difference

Flowering plant embryology is separated into two distinct categories, the Monocots and the Dicot. The word “cot” is derived from cotyledons (vein), means leaves. If it has one leaf it is termed mono cotyledon while if two it is called the Dicot. Plants differ not only in leaves, it also includes root, stem and flowers as well. The major difference between a Monocot stem and a Dicot stem is that, monocot arranges the vascular tissue “sporadically” while Dicot arranges it in “doughnut” shape and is well differentiated. The stem is in charge of supporting the whole plant and helps it to attain sunlight as much as possible for photosynthesis.

Monocot Stem

A Monocot stem is bounded by a layer of epidermis. This epidermis is made up of very closely arranged rectangular cells. It protects the plant from external environment. It is consist of a waxy substance known as cutin. This cutin is responsible to form cuticle layer that stops excessive water loss from the plant. Then is hypodermis which is made up of sclerenchymatous cells. There is no clear demarcation between cortex and vascular bundles are scattered around through the ground tissue. Sclerenchymal sheath bounds the vascular bundles. They are collateral and closed. Phloem is present outside the xylem. Xylem is y shaped. Meta- xylem at the two ends of y, and two proto xylem at its base. Protoxylum disintegrates to form lysogenous cavity. There is no secondary growth. Examples of monocot are wheat, maize, rice and sugarcane.

Dicot Stem

Dicot stem is bound by layer of epidermis. It has trachoma and stomata present in it. Next to epidermis is cortex. Cortex is well differentiated into three different regions. Upper is hypo-dermis- made up of cholenchymatous cells which strengthen the young stem, middle is general cortex- made up of parenchymatous cells with large intercellular space and also has resin canals. Its function is to store food. Inner most layers are endo-dermis- made up of barrel shaped starch cells. It also has a paricycle layer that separates the cortex from vascular bundles. The vascular bundles are arranged in a ring. They are conjoint, collateral, open and endarch. Open means there is cambium between xylem and phloem. Meta xylem is at peripheries and proto-xylem is towards the centre of the stem. Medullary rays between the adjacent medullary structures. They are responsible for food transfer. Central tissue is the pith, at primary phase it stores food, but secondarily given mechanical strength to the stem. Examples of Dicot are arepea, rose, apple, sunflower and sarson etc.

Key Differences

  • Monocot has one cotyledon and Dicot has two.
  • In epidermis or monocot, trochomes are absent and cuticle is present while in Dicot has both.
  • In monocot hypodermis is made-up of sclerenchymal cells while in Dicot it is made-up of cholenchymatous.
  • The ground tissue of monocot is undifferentiated, while in Dicot, it is differentiated into cortex, endodermis, pericycle, medullary rays and pith.
  • There are numerous vascular bundles in monocot while there are eight in Dicot.
  • The vascular bundles are irregularly scattered in monocot while it is in the form of broken rings in Dicot.
  • The bundle cap is absent in monocot while present in Dicot.
  • The bundle sheath is present in monocot while absent in Dicot.
  • The vascular bundles in monocot are conjoint, collateral and closed with endarch xylem while in Dicot it is conjoint, collateral and open with endarch xylem.
  • Monocot has only two of the proto-xylem in each bundle while Dicot has many.

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