Tag: internal structure of root, stem and leaf

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Questions Related to internal structure of root, stem and leaf

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

Lysigenous cavity and Y-shaped xylem occurs in

  1. Dicot stem

  2. Monocot root

  3. Monocot stem

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

Lysigenous intercellular spaces is type of intercellular space arises through dissolution of entire cells, which are therefore called as lysigenous cavity. These cavities of intercellular spaces store up water, gases and essential oils in them. The examples are commonly found in water plants and many monocotyledonous stems. The secretory cavities in Eucalyptus, Citrus and Gossypium are good examples. In monocot stem  the vascular bundle encloses both xylem and phloem. Xylem is found towards the inner surface and phloem towards the outer surface. Cambium is absent. Hence, the vascular bundles are described as conjoint, collateral and closed. In the xylem, there are two metaxylem and two protoxylem vessels arranged in the shape of Y. 

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

Which type of vascular bundles are found in monocot stem?

  1. Collateral, open, endarch

  2. Radial, open, diarch

  3. Radial, open, mesarch

  4. Collateral, closed, endarch
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Monocot stem vascular bundles are found irregularly scattered in the ground tissue. Towards the periphery, the bundles are smaller in size while towards the centre, they are larger in size. The smaller bundles are younger, while the larger ones are older. Hence, the arrangement is described as centrifugal. 

Each vascular bundle has a covering, called as bundle sheath formed by a single layer of sclerenchyma cells. The vascular bundle encloses both xylem and phloem. Xylem is found towards the inner surface and phloem towards the outer surface. Cambium is absent. Hence, the vascular bundles are described as conjoint, collateral and closed. 

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

Hard bast (bundle cap) occurs in

  1. Sunflower stem

  2. Wheat stem

  3. Sunflower root

  4. Both of (A) and (C)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hard bast is the patch of sclerenchyma present on outside of each vascular bundle, thereby forming a bundle cap over each bundle. They serve to provide additional mechanical support to the stem and are present in Sunflower stem. Wheat stem represent a monocot stem in which each vascular bundle is surrounded by thick walled bundle sheath, they do not have hard bust. Root is marked by presence of primary xylem and phloem in different radii, separated from each other.
Therefore, the correct answer is option A.

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

Which type of vascular bundles are found in monocot stem?

  1. Collateral, open, endarch

  2. Radial, open, diarch

  3. Radial, open, mesarch

  4. Collateral, closed, endarch
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Monocot stem vascular bundles are found irregularly scattered in the ground tissue. Towards the periphery, the bundles are smaller in size while towards the centre, they are larger in size. The smaller bundles are younger, while the larger ones are older. Hence, the arrangement is described as centrifugal or endarch. 

Each vascular bundle has a covering, called as bundle sheath formed by a single layer of sclerenchyma cells. The vascular bundle encloses both xylem and phloem. Xylem is found towards the inner surface and phloem towards the outer surface. Cambium is absent. Hence, the vascular bundles are described as conjoint, collateral and closed. 

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

In monocot stems, secondary growth cannot occur, because vascular bundles are

  1. Scattered

  2. Open

  3. Closed

  4. Radial
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Secondary growth refers to the growth that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken, while primary growth is growth that occurs as a result of cell division at the tips of stems and roots, causing them to elongate and gives rise to primary tissue. 

In monocot stem vascular bundles are closed, because cambia is absent. So, secondary growth can not occur
So, the correct answer is ' Closed'

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

What is the characteristics of a vascular bundle of monocot stem?

  1. Open and surrounded by a sclerenchymatous bundle sheath

  2. Closed and not surrounded by bundle sheath

  3. Closed and surrounded by bundle sheath

  4. Open and not surrounded by a bundle sheath
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In a monocot stem the vascular bundles are not arranged in a circle but are usually scattered throughout the ground tissue. There is no clearly defined pith as there is in many dicotyledonous species. 

The vascular bundles of monocotylenous plants do not contain a layer of meristematic tissue (cambium) as the dicots do. Thus, no new cells can be formed inside the vascular bundles of monocots and their vascular bundles are termed as closed, whereas those of dicot plants are open. Bundle sheath is developed either partly or completely surrounding the vascular bundle. Thus, option C is correct.

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

The character of monocot is

  1. Net-veined leaves

  2. Annual rings

  3. Seed with two masses of stored food

  4. Conducting strands scattered in ground tissue
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In a monocotyledenous stem the vascular bundles are not arranged in a circle but are usually scattered throughout the ground tissue. There is no clearly defined pith as there is in many dicotyledonous species. 

As in the dicots the xylem of the bundles is pre-orientated toward the middles of the stem. The vascular bundles of monocotylenous plants do not contain a layer of meristematic tissue (cambium) as the dicots do. Thus no new cells can be formed inside the vascular bundles of monocots and their vascular bundles are termed closed whereas those of dicot plants are open. So, no annual rings in monocots as, there is no secondary growth. 
Net veined leaves and seed with two masses of stored food are characteristics of dicots. Thus, option D is correct.

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

An example of monocots showing secondary growth in stem is

  1. Lilium

  2. Cocos

  3. Asparagus

  4. Yucca
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Secondary growth is increase in the circumference / girth of the plant organs due to the formation of secondary tissues in stelar and extra stelar regions. Normally secondary growth takes place in roots and stem of dicotyledons and gymnosperms. Due to lack of cambium in monocotyledons, secondary growth is absent. But exceptionally, secondary growth takes place in some monocotyledons, such as palm, Yucca, Dracaena etc. 

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

Conjoint, collateral and closed vascular bundles are found in

  1. Monocot stem

  2. Monocot root

  3. Dicot stem

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

In monocot stem vascular bundles are found irregularly scattered in the ground tissue. Towards the periphery, the bundles are smaller in size, while towards the centre, they are larger in size. The smaller bundles are younger, while the larger ones are older. Hence, the arrangement is described as centrifugal. 

Each vascular bundle has a covering called as 'bundle sheath' formed by a single layer of sclerenchyma cells. 
The vascular bundle encloses both xylem and phloem. Xylem is found towards the inner surface and phloem towards the outer surface. Cambium is absent. Hence, the vascular bundles are described as conjoint, collateral and closed.