Biology · Science General

Botany and Plant Science

5,038 Questions

Botany and plant science delve into the biological study of plant life, covering structural anatomy, physiological processes, and reproductive mechanisms. Key topics include inflorescence patterns, root modifications, and seed development, which are vital for biology sections in medical entrance exams. This collection of practice questions helps solidify understanding of complex plant functions.

Plant ReproductionPlant AnatomyRoot ModificationsInflorescence PatternsPlant Morphology

Botany and Plant Science Questions

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

A typical monocotyledonous root is characterized by 

  1. Usually more than six xylem bundles

  2. Large and well developed pith

  3. No secondary growth

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A typical monocotyledonous root can be characterized by :-
1) The xylem shows a polyarch condition where it forms numerous groups or bundles (usually 12 to 21).
2) The cambium is absent in all the stages and there is no secondary thickening in such roots.
3) The pith is large and well developed.
So, the correct answer is 'All of the above'.
Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

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

Net-veined leaves, annual rings and seed with two masses of stored food are characteristic features of dicots. 

In a monocotyledenos, 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. 

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

In monocots, root cap is formed by

  1. Dermatogen

  2. Calyptrogen

  3. Wound cambium

  4. Vascular cambium
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Dermatogen is the histogen or meristematic regions of root and stem which is produced by apical meristem and give rise to uniseriate epidermis by anticlinal divisions; option A is incorrect. Monocotyledons have one additional histogen along with dermatogens, periblem and plerome Calyptrogen being the fourth one that makes root cap. The vascular cambium, also called as wood cambium, has thin walled highly vacuolated cells of two types, the fusiform initials and the ray initials. The fusiform initials are the elongated cells that give rise to secondary xylem and secondary phloem. Ray initials are horizontally organized and produce vascular rays (medullary rays or ray parenchyma). 

Thus, the correct answer is option B.

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

Monocot root differs from dicot root in having

  1. Open vascular bundle

  2. Scattered vascular bundle

  3. Large pith

  4. No pit
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pith is the innermost region of the root representing the central axis. It is composed of few loosely arranged parenchyma cells. Large pith is present in monocot roots. In dicot roots, pith is absent. Open vascular bundles are present in dicots. Scattered vascular bundles are present in moncot stem. Radial vascular bundles are present in both monocot and dicot roots.

Thus, the correct answer is option C.

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

Polyarch and exarch vascular bundles are the characteristic of

  1. Dicot stem

  2. Dicot root

  3. Monocot stem

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

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 in them. 

Monocot stem vascular bundles are conjoint, collateral and closed. Xylem is endarch in them. Presence of only two protoxylem and two metaxylem vessels in each bundle. 
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. 
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. Thus, option D is correct.

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

Which of the following is correct sequence of layers in typical monocot root from outside to inside?

  1. Pericycle, cortex, endodermis, epiblema

  2. Epiblema, endodermis, cortex, pericycle

  3. Epiblema, cortex, endodermis, pericycle

  4. Epiblema, pericycle, cortex, endodermis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The sequence of layers in typical monocot root from outer surface to inside is epiblema, cortex, endodermis, stele, pericycle, conjunctive tissue, pith and vascular bundles. Thus, option C is correct.

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

Passage cells are more distinct in endodermis of

  1. Dicot stem

  2. Monocot stem

  3. Dicot root

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

Passage cells are endodermal cells of older monocot roots which have retained thin walls and Casparian strips rather than becoming suberized and waterproof like the other cells around them, to continue to allow some symplastic flow to the inside. Experimental evidence suggests that passage cells function to allow transfer of solutes such as calcium and magnesium into the stele, in order to eventually reach the transpiration system. For the most part, however, old roots seal themselves off at the endodermis, and only serve as a passageway for water and minerals taken up by younger roots "downstream". Passage cells are absent in dicot roots, monocot stem and dicot stem.

Therefore, the correct answer is option D.

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

Passage cells are found in

  1. Monocot root

  2. Monocot stem

  3. Aerial root

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

Passage cells are endodermal cells of older roots which have retained thin walls and Casparian strips rather than becoming suberized and waterproof like the other cells around them, to continue to allow some symplastic flow to the inside. Passage cells function to allow transfer of solutes, such as calcium and magnesium into the stele, in order to eventually reach the transpiration system. 

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

Exarch and polyarch xylem strands are found in

  1. Monocot stem

  2. Dicot stem

  3. Monocot root

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

In 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 in monocot root.

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

A common character of monocot and dicot roots is

  1. Exarch protoxylem

  2. Endarch xylem

  3. Number of xylem strands

  4. Occurrence of secondary growth
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The anatomy of dicot root and monocot root more or less similar in majority of characters. They are epidermis, general cortex, endodermis, type of vascular bundles, nature of xylem.

The common characters appear between the anatomy of dicot root and monocot root are 
Presence of single-layered epidermis
Presence of parenchymatous general cortex
Presence of single-layered endodermis with Casparian bands.
Presence of radial vascular bundles
Presence of exarch xylem.
So, the correct option is 'Exarch protoxylem'.

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

Pick u the wrong differences between dicot and monocot root.

Character Dicot Root Monocot Root
(a) Activity of pericycle Lateral root production Secondary growth and cambium
(b) Vascular bundle Diarch to tetrarch Polyarch
(c) Cambium Lateral, developed Absent
(d) Pith Well developed Poorly developed

  1. b, d

  2. a, c

  3. a, d

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

a) Wrong – because in dicot root pericycle is meant for production of lateral roots and cambium whereas in monocot root it is pericycle is meant for lateral production only.

b) True – In dicot root stele is diarch to tetrarch, whereas in monocot root, stele is polyarchy.

c) True – In dicot root, cambium is developed laterally, whereas in monocot root, cambium is absent.

d) False – because, in dicot root is pith is poorly developed, whereas in monocot root pith is well developed.

So, the correct option is ‘a,d’.

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root
Which plant part possesses polyarch condition of vascular bundles with a well developed pith?

  1. Dicot root

  2. Monocot root

  3. Dicot stem

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

A monocot root possesses polyarch (more than 4) condition of vascular bundle, here the vascular bundles are radial, closed with exarch condition of the xylem, embedded in the ground tissue that has a well developed central region or the pith or medulla.

So, the correct answer is 'Monocot root'

Multiple choice botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root
Polyarch vascular bundles generally occur in

  1. Monocot stem

  2. Dicot stem

  3. Dicot root

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

Polyarch vascular bundle (more than 4)  is observed in monocot root. The vascular bundle is radial and closed, with exarch condition of the xylem. 

So, the correct answer is 'Monocot root'

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

A typical monocotyledonous root is characterised by -

  1. Usually more than six xylem bundles

  2. Large and well developed pith

  3. No secondary growth

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
A typical monocotyledonous root can be characterized by: -
1) The xylem shows a polyarch condition where it forms numerous groups or bundles (usually 12 to 21).
2) The cambium is absent in all the stages and there is no secondary thickening in such roots.
3) The pith is large and well developed.
So, the correct answer is 'All of the above'.