Tag: internal structure of dicot stem

Questions Related to internal structure of dicot stem

In a dicotyledonous stem, the sequence of tissues from the outside to the inside is

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

  1. Phellem - Pericyele - Endodermis - Phloem

  2. Phellem - Phloem - Endodermis - Pericycle

  3. Phellem - Endodermis - Pericycle - Phloem

  4. Pericycle - Phellem - Endodermis - Phloem

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Correct Option: C
Explanation:

Phellem is outermost layer of cork cambium, which is suberised. Hence, this is the first layer to be found. 
Endodermis is one the layer of cortex, which is to be found under the phellem.
Pericycle is the layer present between endodermis and vascular bundles. 
Dicotyledonous stem possess conjoint, collateral vascular bundle, where xylem is internal and phloem is external. Therefore, phloem is to be encountered after the pericycle. Hence, option C is correct. 

Collenchymatous hypodermis is characteristic feature of

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

  1. Dicot stem

  2. Monoct stem

  3. Monocot as well as dicot stem

  4. Hydrophytes

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Correct Option: A
Explanation:

Dicot stem hypodermis is a region lying immediately below the epidermis. It is represented by a few layers of collenchyma cells with angular thickenings. The cells are compactly arranged without any intercellular spaces. Hypodermis provides mechanical support and additional protection. 

Monocot stem hypodermis is represented by a few layers of compactly arranged sclerenchyma cells. 
Hypodermis in hydrophytes is poorly developed. Its cells are extremely thin walled, which are not collenchymatous. Thus, option A is correct.

Collateral, open vascular bundle and eustele is present in

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

  1. Dicot stem

  2. Monocot stem

  3. Monocot root

  4. Dicot Root

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Correct Option: A
Explanation:

Dicot stem vascular bundles are eight in number, arranged in form of a broken ring. The vascular bundles are conjoint, collateral and open. Xylem is on the inner surface and phloem on the outer surface. Xylem is described as endarch. 

Dicot root vascular bundles are described as radial and tetrarch. There are four bundles each of xylem and phloem occurring alternately. Xylem is described as exarch. 
Monocot root vascular bundles are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Xylem is described as exarch. 
Monocot stem vascular bundles are described as conjoint, collateral and closed. 
Eustele is present in most of seed plant stems. Thus, option A is correct.

Normally in dicot stems, phellogen develops from

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

  1. Hypodermis

  2. Phellem

  3. Endodermal cells

  4. Epidermal & pericycle cells

Show answer
Correct Option: A
Explanation:

In dicot stem, hypodermis is a region lying immediately below the epidermis. It is represented by a few layers of collenchyma cells with angular thickenings. The cells are compactly arranged without any intercellular spaces. Hypodermis provides mechanical support and additional protection. Phellogen is the secondary lateral meristem that may arise from permanant living cells of hypodermis or outer cortex. It is composed of single layer of meristematic cells. 

Collateral, open vascular bundle and eustele is present in

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

  1. Dicot stem

  2. Monocot stem

  3. Monocot root

  4. Dicot root

Show answer
Correct Option: A
Explanation:

Dicot stem vascular bundles are eight in number, arranged in form of a broken ring. The vascular bundles are conjoint, collateral and open. Xylem is on the inner surface and phloem on the outer surface. Xylem is described as endarch. 

Dicot root vascular bundles are described as radial and tetrarch. There are four bundles each of xylem and phloem occurring alternately. Xylem is described as exarch. 
Monocot root vascular bundles are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Xylem is described as exarch. 
Monocot stem vascular bundles are described as conjoint, collateral and closed. Eustele is present in most of seed plant stems. Thus, option A is correct.

Fascicular cambium is the cambium of vascular bundle of

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

  1. Monocot stem

  2. Dicot stem

  3. Monocot leaf

  4. Dicot leaf

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Correct Option: B
Explanation:

Intrafascicular cambium is present between xylem and phloem in dicot stem. It is also termed as fascicular cambium. This meristematic area spreads laterally from each bundle and eventually becomes continuous, forming a complete vascular cambium.

Two cross-sections of stem and root appear simple, when viewed by naked eye. But under microscope, they can be differentiated by

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

  1. Exarch condition of root and stem

  2. Endarch condition of stem and root

  3. Endarch condition of root and exarch condition of stem

  4. Endarch condition of stem and exarch condition of root

Show answer
Correct Option: D
Explanation:

Endarch is the arrangement in which the protoxylem is directed towards the centre and metaxylem elements towards the periphery. The development of the xylems in this arrangement follows the centrifugal pattern. It is the characteristics of the stem of flowering plants.

Whereas exarch is the arrangement in which the protoxylem is directed towards the periphery and metaxylem towards the centre. The development of the xylem in this arrangement follows the centripetal pattern. It is the characteristics of roots.

In dicot stems, vascular cambium is formed from ________.

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

  1. Procambium

  2. Cambium

  3. Promeristem

  4. Protoderm

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Correct Option: A
Explanation:
  • The vascular cambium makes up the growth layer in the stems and roots of many plants (in dicots- buttercups etc) 
  • They are unspecialized cylindrical meristematic cells that divide to form secondary vascular tissues.
  • The vascular cambium is derived from the procambium which is present in the vascular bundles and the interfascicular parenchyma cells which are present between the vascular bundles
  • So, the correct answer is 'Procambium'

Oldest part of phloem in a dicot stem is situated just.

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

  1. Outside vascular cambium

  2. Inner to primary cortex

  3. Inner to vascular cambium

  4. Between periderm and primary cortex

Show answer
Correct Option: B
Explanation:

In dicot stem during secondary growth, the oldest part of xylem situated towards outer to the medulla and oldest phloem is situated just towards inner to the primary cortex.

So, the correct option is ‘Inner to primary cortex’.

The endarch condition is characteristic of

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

  1. Root

  2. Stem

  3. Leaves

  4. Petiole

Show answer
Correct Option: B
Explanation:

A. Root – protoxylem is towards the pericycle and metaxylem is towards the medulla. It is called Exarch.

B. Stem – protoxylem is towards the medulla and metaxylem is towards the pericycle. It is called Endarch.

C. Leaves – the position of protoxylem and metaxylem is not specified.

D. Petiole – the position of protoxylem and metaxylem is not specified.

So, the correct option is ‘stem’.