Internal structure of leaf (dicot and monocot) - class-XI

Generally, the patterns of the leaf veins, or vascular bundles are pinnate and the veins are free; that is, they all diverge and never coalesce, either along their sides or at the ends. So, the incorrect statement is all vascular bundles have different size in leaf showing parallel venation.

In dorsiventral leaf, epidermis is in two layers, one on each surface of the leaf. Both the layers are composed of compactly arranged, barrel-shaped cells. Intercellular spaces are absent. A cuticle surrounds both the layers. Multicellular hairs called as trichomes are present on both the layers. Stomata occur only in the lower epidermis. This condition is described as hypostomatic. 

Bulliform cells or motor cells are large, bubble shaped epidermal cells that occur in groups on the upper surface of the leaves of many grasses. Loss of turgor pressure in these cells causes leaves to roll up during water stress. During drought, the loss of moisture through vacuoles induces bulliform cells to cause the leaves of many grass species to close as the two edges of the grass blade fold up toward each other. Once, adequate water is available, these cells enlarge and the leaves open again. Bulliform cells are absent in dicot leaves. 
Thus, the correct answer is option B.

Leaves, in which both sides appear in equally green color are called isobilateral leaves. It is due to the presence of spongy parenchyma.

So, the correct option is ‘both the surface are equally green’.

Many grass leaves, folds during drought conditions and unfolds during moisturized conditions. It is due to the presence of large, thin-walled cells present on the adaxial side of the upper epidermis, called Bulliform cells.

So, the correct option is ‘Bulliform cells’.

The ligule is a part of the leaf that is found at the junction of the leaf blade and sheath of the leaf. It may take several forms. But commonly, it is a translucent membrane or a fringe of hairs. It is seen in plants belonging to the family Poaceae. Hence, ligule occurs on the leaf of Barley, Oat and Rice.

Grasses have monocot leaves. Leaves of grasses have specialized bulliform cells on the upper epidermis. These bulliform cells are capable of folding and unfolding of leaves to help in the process of transpiration. 

A ligule is a thin outgrowth which is found at the junction of sheathing leaf base (leaf base is broad and surrounds the stem as an envelope) and leaf blade. It is commonly a form of a translucent membrane or a fringe of hairs. The ligule appears to be a continuation of the leaf sheath and encircles the stem as done by the leaf sheath.

Leaf having stomata equally distributed on both surfaces is called amphistomatic (isobilateral) leaf, e.g., most monocot leaves.

The large sized, thin-walled, water containing colourless epidermal cells present on the adaxial epidermis of an isobilateral leaf or monocot leaf are called bulliform cells.

So, the correct option is ‘Isobilateral leaf’.

The large sized, thin-walled, vacuolated, water containing colourless epidermal cells present on the adaxial epidermis of an isobilateral leaf or monocot leaf are called Bulliform cells. They differ from other cells in being size, structure and function.

So, the correct option is ‘large, thin-walled, vacuolated containing water’

In the monocot leaf, mesophyll is undifferentiated, shows spongy parenchyma with oval-shaped cells.

So, the correct option is ‘Mesophyll not differentiated into palisade and spongy tissues'.

A.Isobilateral leaves – Mesophyll is undifferentiated, contains spongy parenchyma only.

B.Dorsiventral mesophytic leaves – Mesophyll is differentiated into upper palisade parenchyma and lower spongy parenchyma.

C.Dorsiventral xerophytic leaves – Mesophyll is differentiated into upper and lower palisade parenchyma and middle spongy parenchyma.

D.Vertical leaves - Mesophyll is differentiated into upper and lower palisade parenchyma and middle spongy parenchyma.

So,
the correct option is ‘isobilateral leaves’.

In isobilateral leaves or monocot leaves, stomata are present on both upper or adaxial epidermis as well as lower epidermis or abaxial epidermis.

So,
the correct option is ‘Both upper and lower surfaces’.

Dicot leaf differs from monocot leaf anatomically in terms of presence of more number of stomata in the lower epidermis, presence of differentiated mesophyll,  and vascular bundle.

Leaf, in which both surfaces are similar in appearance are called isobilateral leaves. These are found in monocotyledons. It is due to the presence of spongy parenchyma.

So, the correct option is ‘Similarly two green surfaces’.    

Palisade parenchyma cells are plant cells found within the mesophyll in leaves, right below the upper epidermis and cuticle. They are vertically elongated, a different shape from spongy mesophyll cells beneath them in the leaf. Their chloroplasts absorb a major portion of the light energy used by the leaf. 

Palisade cells are plant cells found within the mesophyll in leaves, right below the upper epidermis and cuticle. They are vertically elongated, a different shape from spongy mesophyll cells beneath them in the leaf. Their chloroplasts absorb a major portion of the light energy used by the leaf. Palisade cells occur in dicotyledonous plants and also in the net-veined monocots. The spongy mesophyll are usually ball-shaped with large intercellular spaces but usually contains fewer chloroplasts than the palisade cells. They are also present in dicot leaf. 

Stomata is a pore, found in the epidermis of leaves, used to control gas exchange. The pore is bordered by a pair of specialized parenchyma cells, known as guard cells that are responsible for regulating the size of the opening. Stomata are present in the sporophyte generation of all land plant groups except liverworts. 

Dorsiventral leaf i.e. Mesophyll is the ground tissue and it occurs between the two epidermal layers. It is heavily composed of chlorenchyma cells. The mesophyll is differentiated into two regions an upper palisade parenchyma and lower spongy parenchyma. Palisade parenchyma is again composed of two or three layers of elongated and compactly arranged chlorenchyma cells.

Also, the isobilateral leaf has undifferentiated mesophyll.

Therefore, the correct answer is option B.

Leaves, in which both surfaces are differentiated are called dorsiventral leaves. In these leaves, palisade parenchyma is present towards the upper epidermis and spongy parenchyma is present towards the lower epidermis. Because of this reason, in dorsiventral leaves, the upper side is dark green in colour and lower side is light green in colour.

So, the correct answer is ‘Upper surface is dark green as compared to the lower surface’.

The parenchyma with loosely arranged cells, present in the mesophyll of leaves is called spongy parenchyma.

So, the correct option is ‘Loosely arranged’

In xerophytic leaves, mesophyll is differentiated into palisade and spongy parenchyma. In these leaves, palisade parenchyma is present on both sides. i.e towards upper epidermis and lower epidermis. In the palisade parenchyma cells are cylindrical in shape contains more number of chloroplasts. In spongy parenchyma, cells are oval in shape, loosely arranged, with less number of chloroplasts. 

The region present between the upper and lower epidermis of leaves is called mesophyll. It is differentiated into upper palisade and lower spongy parenchyma in dicot leaves or dorsiventral leaves, whereas in monocot leaves or isobilateral leaves, it is undifferentiated and it shows spongy parenchyma.

So, the correct option is ‘All dorsiventral leaves’.

a-bulliform cells                3) Grasses

b)Pericycle                         1) Initiation of lateral roots

c)Endarch xylem                5)stem

d)Exarch xylem                  2)Root

e)Bundle sheath cells       3)Grasses

So,
the correct option is ‘a-3, b-1, c-5, d-2, e-4

The correct botanical matches are: Sal (Shorea robusta), Shisham (Dalbergia sisso), Chir (Pinus roxburghii), and Teak (Tectona grandis). This corresponds to A-4, B-3, C-1, D-2.

Transpiration is the evaporative loss of water by plants. It occurs mainly through the stomata in the leaves. Usually the lower surface of a dorsiventral (often dicotyledonous) leaf has a greater number of stomata while in an isobilateral(often monocotyledonous) leaf. There are almost equal number of stomata on both surfaces.

Dorsiventral leaves orient themselves at an angle to the main axis and perpendicular to the direction of sunlight. Most dicots have dorsi-ventral leaves that are net-veined, including most trees, bushes, garden plants and wildflowers. Mesophyll is the ground tissue between the upper and lower epidermis. In dorsiventral leaf, it is differentiated into palisade parenchyma and spongy parenchyma. Palisade parenchyma lies towards the upper epidermis and consists of one, two or three layers of elongated cells, densely packed with no intercellular spaces and contains chloroplast

In the vascular bundles of dicot leaves, xylem and phloem are present on same radius and also present side by side. So they are called collateral and conjoint. Cambium is absent between xylem and phloem. So, It is called closed vascular bundle.

A dorsiventral organ is one that has two surfaces differing from each other in appearance and structure, as an ordinary leaf. This term has also been used as a synonym for dorsoventral organs, those that extend from a dorsal to a ventral surface. Dorsi-ventral leaves which usually orient at an angle to the main axis and held perpendicular to the direction of sunlight. An isobilateral leaf is usually vertically oriented to expose both surfaces to the sun. The leaves hang vertically to expose one face directly to the drying sun, then the other face. They have equal numbers of stomata in matching quantities and surface qualities of cuticle on both faces of the leaf. Epistomatic leaf has stomata on the upper surface only. Hypostomatic leaf having stomata on the underneath, i.e., foliar abaxial surface.

The adaxial (upper) surface of a bifacial leaf is typically exposed to more sunlight, so it has a thicker cuticle to prevent water loss, a darker color due to densely packed palisade parenchyma, and fewer stomata compared to the abaxial surface.

In a dorsiventral leaf the phloem is present towards the lower surface of the leaf. Xylem lies towards upper epidermis and is composed of annular and spirally thickened vessels, tracheids, fibres and xylem parenchyma. The vascular bundles are conjoint, closed and collateral. Mid vein bundle is large, while others are small. 

Palisade cells contain the largest number of chloroplasts per cell, which makes them the primary site of photosynthesis in the leaves of those plants that contain them, converting the energy in light to the chemical energy of carbohydrates. Beneath the palisade mesophyll are the spongy mesophyll cells, which also perform photosynthesis. Spongy cells acts well in high intensity light.

In dorsi ventral leaf, mesophyll is the ground tissue that occurs between the two epidermal layers. It is exclusively composed of chlorenchyma cells. The mesophyll is characteristically differentiated into two regions namely, an upper palisade parenchyma and a lower spongy parenchyma. Palisade parenchyma is composed of two or three layers of elongated, compactly arranged chlorenchyma cells. Intercellular spaces are absent. The cells contain a very large number of chloroplasts. Spongy parenchyma is composed of a few layers of loosely arranged spherical or oval chlorenchyma cells with prominent intercellular spaces. These cells contain very few chloroplasts. In isobilateral leaf, mesophyll is ground tissue that occurs between the two epidermal layers. It is composed of many layers of loosely arranged, spherical or oval chlorenchyma cells. Intercellular spaces are prominent. Mesophyll is not differentiated in spongy and palisade tissue. 
Therefore, the correct answer is option B.

Dorsiventral leaf - Mesophyll is the ground tissue that occurs between the two epidermal layers. It is exclusively composed of chlorenchyma cells. The mesophyll is characteristically differentiated into two regions namely, an upper palisade parenchyma and a lower spongy parenchyma. Palisade parenchyma is composed of two or three layers of elongated, compactly arranged chlorenchyma cells. Intercellular spaces are absent.

In dorsiventral leaves, mesophyll is the ground tissue that occurs between the two epidermal layers. It is exclusively composed of chlorenchyma cells. The mesophyll is characteristically differentiated into two regions namely, an upper palisade parenchyma and a lower spongy parenchyma. Dorsiventral leaves are present in dicots. In an isobilateral leaves, undifferentiated mesophyll is present. These leaves are present in monocots. Dorsiventral leaves are absent in extremely xerophytic leaves and hydrophytic leaves. 
Thus, the correct answer is option D.

Stoma (plural stomata) is a pore, found in the epidermis of leaves, stems and other organs that is used to control gas exchange. Monocots have isobilateral leaf and dicots have dorsiventral leaf. Dicotyledons usually have more stomata on the lower epidermis than the upper epidermis. Monocotyledons, on the other hand, usually have the same number of stomata on the two epidermis. In plants with floating leaves, stomata may be found only on the upper epidermis and submerged leaves may lack stomata entirely.
Thus, the correct answer is option B.

In the dorsiventral leaf or dicot leaf, mesophyll is differentiated into palisade parenchyma and spongy parenchyma. Palisade parenchyma is present on the upper side and spongy parenchyma is present on the lower side.

The region present between the upper and lower epidermises is called mesophyll. In dicot leaves, mesophyll is differentiated into upper palisade parenchyma and lower spongy parenchyma. It is found in dicot leaves.

So, the correct answer is ‘Dicot leaves’

In dorsiventral leaf, more number of stomata occur on lower epidermis and less number of stomata present on upper epidermis.

So, the correct option is ‘occur on lower epidermis'.

in dorsiventral or dicot leaf, midirib or main vein represents the vascular bundles. In this, xylem is present towards upper epidermis and phloem present towards the lower epidermis. These are collateral, conjoint, closed the position of protoxylem and metaxylem is not specified clearly.

So, the correct answer is 'Adaxial and abaxial respectively'.

In dorsiventral leaves, less stomata are present in the upper epidermis and more stomata are present on the lower epidermis.

So, the correct option is ‘Fewer on upper surface and more on lower surface’.

Stele with four vascular bundles is called tetrarch stele. it is generally found in dicotyledons. In the vascular bundles xylem and phloem are on different raidii. So the vascular bundles are called radial vascular bundles. In the xylem protoxylem is faced towards the pericycle and metaxylem is faced towards the medulla.  eg:Cicer arietinum  roots.