Tag: internal structure of root, stem and leaf

Questions Related to internal structure of root, stem and leaf

Secondary growth does not occur in monocots as their vascular bundles are

  1. Radial

  2. Scattered

  3. Enclosed by sclerenchyma

  4. Closed


Correct Option: D
Explanation:

Secondary growth does not take place in monocotyledons, because of the absence of cambium between xylem and phloem in vascular bundles. These vascular bundles are called closed vascular bundles.

So, the correct option is ‘Closed’.

Grafting is not possible in monocots because they

  1. Lack cambium

  2. Have scattered vascular bundles

  3. Have parallel venation

  4. Are herbaceous


Correct Option: A
Explanation:

In monocot stem, cambium is absent in the vascular bundles. Due to this, grafting is not possible in monocot stem

So, the correct answer is ‘Lack cambium’

Conjoint and closed vascular bundles with no phloem parenchyma are observed in

  1. Monocot stem

  2. Dicot stem

  3. Monocot root

  4. Dicot root


Correct Option: A
Explanation:

A.Monocot stem - conjoint, closed vascular bundles are present, in which phloem parenchyma is absent in the phloem.

B.Dicot stem - Conjoint, open vascular bundles are present, in which phloem parenchyma is present in the phloem.
C.Monocot root - Radial vascular bundles are present, in which phloem parenchyma is absent.
D.Dicot root - Radial vascular bundles are present, in which phloem parenchyma is present.
So, the correct option is 'Monocot stem'.

Which of the following characters is not found in the transverse section of monocot stem?

  1. Sclerenchymatous bundle sheath

  2. Lysigenous cavity

  3. Sclerenchymatous hypodermis

  4. Starch sheath


Correct Option: D
Explanation:

The anatomy of monocot stem shows outer single layered epidermis with cuticle and stomata, sclerenchymatous hypodermis, large, wide parenchymatous ground tissue. In this vascular bundles are scatteredly arranged. So the stele is called Atactostele. Vascular bundles are outerly surrounded by sclerenchymatous fibres. So they are called fibrovascular bundles and are collateral, conjoint, closed with endarch xylem. Protoxylem lacuna is present. General cortex, endodermis, pericycle, medulla and medullary rays are absent.

So, the correct option is ‘Starch sheath’.

Water containing Lysigenous cavity is present within the vascular bundles.

  1. Monocot stem

  2. Dicot stem

  3. Monocot root

  4. Dicot root


Correct Option: A
Explanation:
The vascular bundle showing protoxylem vessels and parenchyma cell which dissolve leading to the formation of water cavity called lysigenous cavity such vascular bundles are found in monocot stem .
So the correct answer is A .

The stele found in monocot is:

  1. Haplostele

  2. Atactostele

  3. Dictyostele

  4. Actinostele


Correct Option: B
Explanation:

The stele is the central part of the root and stem which contains tissues derived from the procambium, in monocots, the vascular bundles are scattered and the stele is an atactostele.

So, the correct option is 'Atactostele'.

Y-shaped arrangement of xylem vessels is found in
  1. Monocot stem

  2. Dicot stem

  3. Monocot root

  4. Dicot root


Correct Option: A
Explanation:

The Y-shaped arrangement of xylem vessels is found in monocot stem, two metaxylem vessels are located at the upper two arms, while the base or the stick of the letter consists of one or two protoxylem vessels.

So, the correct  answer is 'Monocot stem'

Lysigenous cavity in monocot stem vascular bundles develops by the dissolution of
  1. protoxylem

  2. metaxylem

  3. phloem

  4. ground tissue


Correct Option: A
Explanation:

In monocot stem (Maize), the xylem appears Y shaped. The lowermost or innermost protoxylem undergoes disintegration to produce lysigenous cavities also called the protoxylem lacuna.

So, the correct answer is 'protoxylem'

Select the incorrect statement regarding the anatomy of a typical monocotyledonous stem
  1. Phloem parenchyma is absent.

  2. Vascular bundles are scattered, conjoint, collateral and closed

  3. Each vascular bundle is surrounded by a bundle sheath.

  4. Ground tissue is differentiated into cortex, endodermis, pericycle and pith


Correct Option: D
Explanation:

In a monocot stem (Example Maize), the stem is differentiated into Epidermis, hypodermis and ground tissue. In the ground tissue are embedded vascular bundles that are conjoint, colateral and closed.The vascular bundles are not enclosed by endodermis and pericycle.

So, the correct answer is 'Ground tissue is differentiated into cortex, endodermis, pericycle and pith'

Schlerenchymatous hypodermis is found in?

  1. Dicot root

  2. Monocot leaf

  3. Dicot stem

  4. Monocot stem


Correct Option: D
Explanation:
The sclerenchymatous hypodermis is present in a monocotyledonous stem. It is 2-3 layered thick and lies below type epidermis. It is made up of thick-walled lignified sclerenchyma fibers.

So, the correct answer is 'Monocot stem'.