18 Major Difference Between Monocot And Dicot Leaf (With Similarities)

Monocot Leaf

Monocot leaves are the leaves which appear on plants produced from seeds with single cotyledon like Maize, Rice, Orchids, Grass, Wheat, Palm trees, Bananas, magnolia tree etc. The leaves are usually ribbon like with parallel venation. Parallel venation means veins in the leaf are arranged in a parallel orientation. Botanically, monocot leaves are said to have isobilateral leaves because both surface of the leaves have same coloration/appearance. Generally, the monocot leaf is slender and long in shape.

Anatomical Structure Of Monocot Leaf

The following arrangement of tissues is seen in a cross-section of a monocot leaf.

• Upper Epidermis
• Mesophyll Tissue
• Vascular Tissue
• Lower Epidermis

Upper Epidermis

Upper epidermis is a single layered tissue that is made up of barrel shaped cells that are arranged closely with no intercellular spaces between them. On any monocot leaf, there is equal number of stomata present on both the surface of epidermis, a condition usually described as amphistomatic. Upper epidermis on its outer surface is covered by a thin cuticle.

On the upper epidermis there is also presence of few large bubble-like cells referred to as motor cell or bulliform cells which are thought to help the leaf bend or fold and thus reducing surface area exposed to sunlight consequently reducing the rate of transpiration.

Mesophyll

Mesophyll is a ground green tissue present in between upper epidermis and lower epidermis. In monocot leaf, the mesophyll is not differentiated into palisade parenchyma and spongy parenchyma. The mesophyll tissue consists of only one kind of cells which are small oval or spherical or irregular shaped spongy parenchyma cells with chloroplasts and chlorophyll.

Vascular Bundles

Vascular tissue is an arrangement of multiple cell types in vascular plants which allows for the transport of water, minerals and products of photosynthesis to be transported throughout the plant.  The vascular bundle also provides strength to the leaf. Each vascular bundle consists of xylem and phloem complex tissues surrounded by bundle sheath. Vascular bundles in monocot leaf can be described conjoint, collateral and closed with endarch xylem.

The vascular bundle is described as closed because there is no cambium present between xylem and phloem. It is also described as conjoint and collateral because phloem and xylem are present on the same radius whereas xylem bundles are described as endarch because the Protoxylem vessels face towards the upper epidermis.

Lower Epidermis

Lower Epidermis is found just below the undifferentiated mesophyll as a single layer of cells and contains stomata and guard cells. The cells are cubical or barrel in shape and arranged very closely without any intercellular spaces. On the, lower epidermis of a monocot leaf, the same number of stomata are present just like in the upper epidermis. In between the epidermal layers of a monocot leaf there is undifferentiated spongy parenchyma with presence of less number of chloroplasts and chlorophyll and thus both surfaces of the leaf appears to be of same coloration.

Monocot Leaf Diagram

Characteristics Of monocot Leaf

• The guard cells of stomata are dumb-bell shaped in monocot leaf.
• The monocot leaf is slender and long in shape.
• The epidermal cells have almost straight lateral walls.
• The orientation of a monocot leaf can be described as isobilateral. Isobilateral orientation is whereby plant leaf surface parts (the upper and lower) are identical to each other.
• Both small and large vascular bundles are present in monocot leaf.
• In a monocot leaf, the hypodermis of the midrib region is sclerenchymatous.
• The upper and lower surfaces of a monocot leaf are equally green.
• The monocot leaf is amphistomatic in nature. This is a condition whereby stomata are present on both surface of the leaf.
• In monocot leaf, large vascular bundles may show differentiation into Protoxylem and meta-xylem elements.
• The intercellular spaces are relatively small due to compact arrangement of mesophyll cells.
• The walls of epidermal cells of a monocot plant leaf have heavy deposition of silica.
• The stomata are arranged in parallel rows and are uniformly present on both surface of the leaf.
• The bundle sheath of a monocot leaf may have a single or double layer and formed of colored cells due to presence of chloroplasts.
• The bundle sheath extension of a monocot leaf is sclerenchymatous.
• The mesophyll of a monocot plant leaf is a single layer and not differentiated into parts.
• The venation pattern of a monocot leaf is parallel. Parallel venation is whereby the secondary veins run parallel to each other off a central, perpendicular primary vein.
• The bulliform (motor cells) are very much present in the epidermis of a monocot plant leaf.
• Protoxylem elements are distinguishable as Protoxylem lacuna.

Also Read: Difference Between Angiosperms And Gymnosperms

Dicot Leaf

Dicot leaves are the leaves which appear on plants produced from seeds with two embryonic leaves or   cotyledon like roses, peas, beans, lentils, peanut, oak trees, daisies, cacti etc. The leaves usually have an interconnection of veins that result to reticulate venation. Reticulate venation means veins in the leaf are arranged or interconnected to form a web-like network. Botanically, dicot leaves are said to have Dorsiventral leaves because both surface of the leaves differ in coloration/appearance and structure. Generally, dicot leaf is broader in shape and relatively small in size.

Anatomical Structure Of Dicot Leaf

The following arrangement of tissues is seen in a cross-section of a dicot leaf.

• Upper Epidermis
• Mesophyll Tissue
• Vascular Tissue
• Lower Epidermis

Upper Epidermis

Upper Epidermis is the outmost layer containing few or no chloroplast. The cells are quite transparent and allow most of the light that strikes them to pass through the underlying cells. The upper surface is covered with a waxy waterproof cuticle which serves to reduce water loss from the leaf. The cuticle on the upper epidermis is thicker than that of lower epidermis. The minute openings found on the epidermis are referred to as Stomata. On any dicot leaf, the stomata are more in number on the lower epidermis than on the upper epidermis.

Lower Epidermis

Lower Epidermis refers to a single layer of cells on the lower surface of the leaf that contains stomata and guard cells. It contains more stomata (thousands per square centimeter) than upper epidermis. Stomata allow the exchange of carbon dioxide, oxygen and transpiration.

Mesophyll Tissue

In the leaf of dicotyledonous plants, the mesophyll layer is differentiated into two types of cells, namely, the palisade parenchyma cells located just below the epidermis and the spongy parenchyma cells that are located below the palisade cells and above the lower epidermis. The function of palisade parenchyma is photosynthesis. Spongy cells are irregularly shaped and loosely arranged with numerous airspaces which facilitate exchange of gases.

Vascular Tissue

The vascular bundles in dicot leaf are large and generally present in the veins of the leaf. The vascular tissues of dicot leaf are conjoint, collateral and closed. Xylem is present towards the upper epidermis while the phloem towards the lower epidermis.

Vascular bundles are surrounded by a compact layer of parenchymatous cells referred to as bundle sheath or border parenchyma. Xylem consists of metaxylems and Protoxylem vessels. Protoxylem vessels are present towards the upper epidermis. Protoxylem vessels are newly formed young vessels while metaxylem vessels are old and well matured vessels.

Phloem consists of sieve tubes, companion cells and phloem parenchyma. Phloem fibres are absent. The xylem consists of vessels and xylem fibres are absent. Generally, vascular bundles help in transportation of water, dissolved minerals and dissolved food material in the leaf; and provide strength to the leaf.

Dicot Leaf Diagram

Characteristics Of Dicot Leaf

• The guard cells of stomata are kidney-shaped in dicot leaf.
• A dicot leaf is broader in shape and relatively small.
• The epidermal cells have sinous lateral walls.
• The orientation of a dicot leaf can be described as dorsiventral. Dorsiventral is whereby one the plant has two surfaces differing from each other in appearance and structure.
• The vascular bundles in dicot leaf are generally large.
• The hypodermis of the midrib region of a dicot plant leaf is collenchymatous.
• The upper surface of a dicot leaf is dark green while the lower surface is light green in color.
• Dicot leaf can be described as This is a condition whereby the stomata are only present on the lower surface of the leaf.
• Dicot leaf large vascular bundles do not show differentiation into Protoxylem elements.
• The intercellular spaces are relatively large due to presence of loosely packed mesophyll cells.
• The walls of epidermal cells of a dicot leaf do not have silica deposition.
• The stomata are arranged randomly on the epidermis of dicot leaf.
• The bundle sheath of a dicot leaf has a single layer and formed of colorless cells.
• The bundle sheath extension of a dicot leaf is parenchymatous.
• The mesophyll of a dicot leaf is differentiated into two parts, the lower spongy mesophyll and upper palisade.
• The venation pattern in a dicot leaf is reticulate. Reticulate venation is whereby vein are interconnected and form a web-like network.
• The bulliform (motor) cells are absent in the epidermis of a dicot plant leaf. Bulliform cells are large bubble-like cells, located just beneath the epidermis, are thought to help the leaf bend or fold.
• Protoxylem elements are indistinguishable.

Also Read: Difference Between C3 And C4 Plants

Difference Between Monocot And Dicot Leaf In Tabular Form

Also Read: Difference Between Evergreen And Deciduous Plant

Similarities Between Monocot Leaf And Dicot Leaf

• Both monocot and dicot leaves have an outer, waxy layer referred to as cuticle that covers the dermal tissue of the upper and lower epidermis.
• Hypodermis is present in both dicot and monocot leaf.
• In both monocot and dicot leaves, the vascular bundles are conjoint and collateral.
• Major portions of the ground tissue in both monocot and dicot leaves is parenchymatous.
• Bundle sheath extension is present in the vascular bundles of both monocot and dicot leaves.
• Chloroplasts are present in the mesophyll of both dicot and monocot leaves.
• The phloem and xylem of both dicot and monocot leaves consists of Protoxylem, Protophloem, Metaxylem and Metaphloem.