Tag: internal structure of dicot stem

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

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

  1. Phellem - Pericyele - Endodermis - Phloem

  2. Phellem - Phloem - Endodermis - Pericycle

  3. Phellem - Endodermis - Pericycle - Phloem

  4. Pericycle - Phellem - Endodermis - Phloem
Reveal answer Fill a bubble to check yourself
C Correct answer
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. 

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

Collenchymatous hypodermis is characteristic feature of

  1. Dicot stem

  2. Monoct stem

  3. Monocot as well as dicot stem

  4. Hydrophytes
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Collateral, open vascular bundle and eustele is present in

  1. Dicot stem

  2. Monocot stem

  3. Monocot root

  4. Dicot Root
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Normally in dicot stems, phellogen develops from

  1. Hypodermis

  2. Phellem

  3. Endodermal cells

  4. Epidermal & pericycle cells
Reveal answer Fill a bubble to check yourself
A Correct answer
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. 

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

Collateral, open vascular bundle and eustele is present in

  1. Dicot stem

  2. Monocot stem

  3. Monocot root

  4. Dicot root
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Fascicular cambium is the cambium of vascular bundle of

  1. Monocot stem

  2. Dicot stem

  3. Monocot leaf

  4. Dicot leaf
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  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
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

In dicot stems, vascular cambium is formed from ________.

  1. Procambium

  2. Cambium

  3. Promeristem

  4. Protoderm
Reveal answer Fill a bubble to check yourself
A Correct answer
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'
Multiple choice botany internal structure of root, stem and leaf internal structure of dicot stem internal structure of stem(dicot and monocot) anatomy of stem

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

  1. Outside vascular cambium

  2. Inner to primary cortex

  3. Inner to vascular cambium

  4. Between periderm and primary cortex
Reveal answer Fill a bubble to check yourself
B Correct answer
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’.

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

The endarch condition is characteristic of

  1. Root

  2. Stem

  3. Leaves

  4. Petiole
Reveal answer Fill a bubble to check yourself
B Correct answer
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’.