Tag: internal structure of stem(dicot and monocot)

Questions Related to internal structure of stem(dicot and monocot)

Endodermis is not differentiated in which of the following 

  1. Monocot root

  2. Dicot root

  3. Monocot stem

  4. Dicot stem


Correct Option: C
Explanation:

In monocot stem, cortex is not differentiated into hypodermis, general cortex and endodermis. In the place of cortex a large, wide region is present called Ground tissue is present. It is parenchymatous, stores water and food materials. In this vascular bundles are present scatteredly.

So, the correct option is ‘monocot stem’

Fibrovascular bundles or vascular bundles covered by sclerenchymatous sheath are found in

  1. Monocot leaf

  2. Monoct stem

  3. Monocot root

  4. Dicot stem


Correct Option: B
Explanation:

A.Monocot leaf – vascular bundles are covered by parenchymatous bundle sheath.

B. Monocot stem – vascular bundles are covered by sclerenchymatous fibres. So these are called fibrovascular bundles.

C. Monocot root – there is no any covering around the vascular bundles.

D. Dicot stem – there is no any covering around the vascular bundles.

So, the correct option is ‘Monocot stem’.

Phloem parenchyma is absent in

  1. Dicot root

  2. Dicot leaf

  3. Monocot stem

  4. Dicot stem


Correct Option: C
Explanation:

A.Dicot root – phloem parenchyma is present.

B.Dicot leaf – Phloem parenchyma is present.

C.Monocot stem – phloem parenchyma is absent.

D.Dicot stem – Phloem parenchyma is present.

So, the correct answer is 'Monocot stem'.

In monocot stem, the pericycle is?

  1. Indistinguishable

  2. One layered

  3. Two layered

  4. Multi layered


Correct Option: A
Explanation:

A T.S. shows conjoint, collateral, endarch and closed bundles scattered in a ground tissue. It is?

  1. Dicot stem

  2. Monocot stem

  3. Dicot root

  4. Monocot root


Correct Option: B
Explanation:

A.Dicot stem – collateral, conjoint, endarch, open vascular bundles present in the form of rings.

B.Monocot stem – collateral, cojoint, endarch, closed vascular bundles present in the form of scattered manner in a ground tissue.

C.Dicot root – radial vascular bundles are present.

D.Monocot root – radial vascular bundles are present.

So, the correct option is ‘Monocot stem’.

Which of these characters does$/$ do not apply to vascular bundle of monocot stem?
I. Conjoint
II. Endarch protoxylem
III. Open
IV. Phloem parenchyma is absent.

  1. I and II only

  2. II and III

  3. III and IV

  4. III

  5. I and IV only


Correct Option: D
Explanation:

I.Conjoint – applicable – because xylem and phloem are present side by side in the vascular bundles.

II.Endarch protoxylem – applicable – because protoxylem is present towards medulla side and metaxylem is present towards the pericycle side.

III.Open – not applicable – because, cambium is absent between the xylem and phloem in the vascular bundles.

IV.Phloem parenchyma is absent – applicable – in the phloem of monocots phloem parenchyma is not present.

So, the correct option is ‘III’

Monocot stem has

  1. Bicollateral closed vascular bundles

  2. Bicollateral open vascular bundles

  3. Collateral open vascular bundles

  4. Collateral closed vascular bundles


Correct Option: D
Explanation:

A.Bicollateral closed vascular bundles – Not present in any plants

B.Bicollateral open vascular bundles – found in the stems of Cucurbitaceae members

C.Collateral open vascular bundles – found in the dicotyledonous stems.

D.Collateral closed vascular bundles – found in the monocotyledonous stems.

So, the correct option is ‘Collateral closed vascular bundles’.

A structure absent in monocot is

  1. Sieve tubes

  2. Stomata

  3. Cambium

  4. Vessels


Correct Option: C
Explanation:

In monocot stem, epidermis, hypodermis, ground tissue, and vascular bundles are present. General cortex, endodermis, pericycle, medulla, medullary are absent. In the phloem, phloem parenchyma is also absent. Xylem and phloem are present on same radii, and also present side by side. So they are also called Collateral and Conjoint vascular bundles. In the vascular bundles, cambium is absent between xylem and phloem, So these are closed vascular bundles. In the xylem, protoxylem is towards the centre, and metaxylem is towards the periphery. So, it is an endarch xylem. 

So, the correct option is 'Pith or cambium'.

Which one is false about monocot stem?
I. Vascular bundles is scattered, cojoint, close, surrounded by sclerenchymatous bundle sheath and cavity.
II. Hypodermis is scelerenchymatous.
III. Peripheral vascular bundles is smaller than centrally placed ones.
IV. Ground tissue is differentiated into cortex, pericycle, pith, etc.
V. Homogeneous parenchymatous ground.

  1. I, III, IV

  2. III, IV

  3. IV

  4. V


Correct Option: C
Explanation:

The monocot stem shows the following characteristics: 

I. Vascular bundles are scattered in the ground tissue, conjoint, collateral and they are surrounded by the sclerenchymatous layer of bundle sheath. They have a lysigenous cavity formed by the breakdown of inner protoxylem vessels and parenchyma.
II. The hypodermis is made up of sclerenchymatous cells.
III. The peripheral vascular bundles are smaller in size and are more than the central vascular bundles.
IV. Ground tissue is not differentiated into cortex, pericycle, pith etc.
V. Ground tissue is homogeneous and is made of parenchymatous cells.
Hence, the correct answer is 'Ground tissue is differentiated into cortex, pericycle, pith etc.'

Vascular bundles are scattered in

  1. Bryophytes

  2. Dicot root

  3. Dicot stem

  4. Monocot stem


Correct Option: D
Explanation:

In monocot stems, the vascular bundles are dispersed. In dicot stems, the vascular bundles are arranged in ring.