Tag: internal structure of root, stem and leaf

Questions Related to internal structure of root, stem and leaf

In monocot leaves, the mesophyll Consists of

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf

  1. Aerenchyma

  2. Only Spongy chlorenchyma

  3. Only Palisade Chlorenchyma

  4. Palisade and Spongy Chlorenchyma

Show answer
Correct Option: B
Explanation:
Mesophyll in monocot leaves lie between the two layers of epidermis and is not differentiated in palisade and spongy tissues. Instead, the undifferentiated mesophyll is similar to spongy tissue. It consists of the mesophyll cells that are chlorenchymatous and contain a number of chloroplasts. 
So the correct answer is 'Only spongy chlorenchyma'.

Cells which help in rolling and unrolling of leaf lamina in grasses are 

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf

  1. Complementary cells

  2. Motor cells

  3. Passage cells

  4. Companion cells

Show answer
Correct Option: B
Explanation:
  • The leaves of monocots have a large bubble-shaped epidermal cell called bulliform cells.
  • They are also known as motor cells.
  • They are present in the adaxial surface of the leaves.
  • They play an important role in the unfolding of the developing leaves and in the rolling and unrolling of mature leaves in response to the alternating wet and dry conditions.
  • So, the correct answer is 'Motor cells'.

Select the true statement for a isobilateral leaf.

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf

  1. The stomata are present on both the surfaces

  2. Mesophyll is differentiated into palisade & spongy

  3. Cuticle is always absent on both surfaces

  4. Vascular bundles are open & conjoint

Show answer
Correct Option: A
Explanation:

Monocot leaves are called isobilateral leaves since both the sides of monocot leaves are more or less similar. Isobilateral leaves orient themselves parallel to the main axis and parallel to the direction of sunlight. Epidermis is single layered, present on both surfaces and has cuticles (cuticularized) and stomata on both surfaces (amphistomatic). It  is composed of compactly arranged oval or barrel shaped thin walled parenchymatous cells. Mesophyll is the ground tissue that is present between the two epidermal layers. Vascular bundles are of two types- small bundles are abundant and larger bundles are found in between them.

So the correct option is 'the stomata are present on both the surfaces'.

The number of types of cells presents in the adaxial epidermis of grasses

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf

  1. $1$

  2. $2$

  3. $3$

  4. $4$

Show answer
Correct Option: A
Explanation:

The upper surface of the leaf is known as the adaxial surface. The type of cells presents in the adaxial epidermis of grasses is bulliform cells (only one type). These are large bubble-shaped cells present in the adaxial or upper surface of the leaves in monocots. So, the correct answer is '1'.

Match the columns.

A) Syntheticauxin  i) Zeatin 
B) Natural cytokinin from coconut milk  ii) IBA
C) naturalauxin  iii) Kinetin 
D) purine from herring sperm DNA iv) NAA
botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

  1. $A-iv,B-i,C-ii,D-iii$

  2. $A-ii,B-i,C-iv,D-iii$

  3. $A-iv,B-iii,C-ii,D-i$

  4. $A-ii,B-iii,C-iv,D-i$

Show answer
Correct Option: A
Explanation:
 A synthetic auxin (NAA) suppresses secondary wall cellulose synthesis and enhances elongation in cultured cotton. Zeatin is a cytokinin derived from adenine, which occurs in the form of a cis- and a trans-isomer and conjugate. Five naturally occurring (endogenous)auxins in plants include indole-3-acetic acid, 4-chloroindole-3-acetic acid, phenylacetic acid, indole-3-butyric acid, and indole-3-propionic acid. The mechanism of production of kinetin in DNA is thought to be via the production of furfural — an oxidative damage product of deoxyribose sugar in DNA — and its quenching by the adenine base's converting it into N6-furfuryladenine, kinetin. So the correct option is
 ' A−iv,B−i,C−ii,D−iii'.

One of the following is absent in the phloem of mostly monocots.

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

  1. Sieve tubes

  2. Phloem parenchyma

  3. Companion cells

  4. Phloem fibres

Show answer
Correct Option: A

Mark out the incorrect statements.


A) Bulliform cells are found on adaxial epidermis of grasses.
B) All vascular bundles have different size in leaf showing parallel venation.
C) Endodermis, pericycle, vascular bundle and pith constitute the stele.
D) Bastfibresare absent in primary phloem.

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

  1. B only

  2. D only

  3. A & B only

  4. B & C only

Show answer
Correct Option: A
Explanation:

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.

Dorsiventral leaf is identified by the presence of

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

  1. Stomata on both the epidermis

  2. Stomata mainly present on the lower epidermis

  3. No stomata on the epidermis

  4. Sunken stomata on the upper epidermis

Show answer
Correct Option: B
Explanation:

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. 

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. Thus, option B is correct.

Bulliform or motor cells occur in

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

  1. Upper epidermis of dicot leaves

  2. Upper epidermis of monocot leaves

  3. Lower epidermis of monocot leaves

  4. Lower epidermis of dicot leaves

Show answer
Correct Option: B
Explanation:

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.

In isobilateral leaves

botany internal structure of root, stem and leaf internal structure of monocot leaf internal structure of leaf (dicot and monocot) anatomy of leaf internal structure of dicot leaf

  1. Lower surface is brighter green

  2. Upper surface is lighter green

  3. Both the surfaces are equally green

  4. Upper surface is dark green while the lower surface is lighter green

Show answer
Correct Option: C
Explanation:

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’.