Tag: botany

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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)

Read the following features and choose the correct option about anatomy of dicot and monocot stem.
(i) Collenchymatous hypodermis.
(ii) Vascular bundles are scattered.
(iii) Eustele.
(iv) Ground tissue is not differentiated.
(v) Pericycle absent

  1. Dicot stem i,ii,iii ; Monocot stem iv,v

  2. Dicot stem i,ii,v ; Monocot stem iii,iv

  3. Dicot stem iii, v; Monocot stem i,ii,iv

  4. Dicot stem i,iii ; Monocot stem ii, iv, v
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Dicot stem has collenchymatous hypodermis, monocots have sclerenchymatous hypodermis.  In each vascular bundle, the xylem and phloem are separated by a substance called vascular cambium. Eustele is similar to the dictyostele except that the bundles lack an endodermis and are collateral. 
Monocots have vascular bundles throughout their ground tissue, their stems do not have a discernible pith; the parenchyma cells in monocot stems are referred to simply as ground tissue. In monocot roots, the pericycle present only produces the lateral roots. 
So the correct option is 'Dicot stem i,ii,iii ; Monocot stem iv,v'.
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, closed and endarch vascular bundles scattered in the ground tissue are found in

  1. Dicot root

  2. Monocot root

  3. Dicot stem

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

Conjoint, collateral, closed and endarch vascular bundles scattered in the ground tissue are found in monocot stem. 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. The vascular bundles of monocotylenous plants do not contain a layer of meristematic tissue.  

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)

Cortex and pith remain indistinguishable in

  1. Monocot stem

  2. Monocot root

  3. Periderm

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

Cortex and pith remain indistinguishable in a monocot stem. The epidermis is a layer of cells that cover the plant body, including the stems, leaves, flowers and fruits, that protects the plant from the outside world. In old stems the epidermal layer, cortex and primary phloem become separated from the inner tissues by thicker formations of cork. But in the monocots the cortex and pith are indistinguishable.
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)

Identify the incorrect statement with respect to monocot stem.
(a) Hypodermis is made up of sclerenchyma
(b) Ground tissue is differentiated
(c) Vascular bundles which are situated towards the centre are larger in size and less in number
(d) Each vascular bundle is conjoint, collateral and closed and xylem is endarch.

  1. a, b and c

  2. b, c and d

  3. only b

  4. b and c
Reveal answer Fill a bubble to check yourself
A Correct answer
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)

Monocot stem are characterized by

  1. Conjoint collateral and open vascular bundle

  2. Conjoint collateral and closed vascular bundle

  3. Radial

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Anatomy of the monocot stem shows that while the vascular bundles are oval in shape, numerous and scattered, it is by nature, conjoint, collateral, closed and endarch without any lysigenous activity.

Therefore, the correct answer is option B.

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.