Biology · Science General

Botany and Plant Science

4,989 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 evs identifying the plants absorption of water from the soil root system the root system

In monocotyledon roots, the histogen present at the apex of the root tip is 

  1. Dermatogen

  2. Periblem

  3. Calyptrogen

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

According to histogen theory, as proposed by Hanstein, the root and shoot apices have three distinct meristematic regions called as histogens. These are namely; dermatogen, periblem and plerome. The dermatogens make uniseriate epidermis by anticlinal divisions, periblem forms cortex and plerome serve as the progenitor of stele (pericycle, vascular bundles, pith rays or medullary rays and pith). Monocotyledons have a fourth histogen, calyptrogen; being the fourth one, that makes root cap. 
Thus, the correct answer is option C.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

How many histogen are present in a monocot root apex?

  1. 1

  2. 2

  3. 3

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

According to histogen theory, as proposed by Hanstein, the root and shoot apices have three distinct meristematic regions called as histogens, these are namely dermatogens, periblem and plerome. The dermatogens makes uniseriate epidermis by anticlinal divisions, periblem forms cortex and plerome serve as progenitor of stele (pericycle, vascular bundles, pith rays or medullary rays and pith). Monocotyledons have four histogens; calyptrogen being the fourth one that makes root cap. 

Thus, the correct answer is option D.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

How many histogens are present in casuarina root apex?

  1. Four

  2. One

  3. Three

  4. Two
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
According to histogen theory, as proposed by Hanstein, the root and shoot apices have three distinct meristematic regions called as histogens. These are namely, dermatogens, periblem, and plerome. The dermatogens make uniseriate epidermis by anticlinal divisions, periblem forms cortex and plerome serve as the progenitor of stele (pericycle, vascular bundles, pith rays or medullary rays and pith). Casuarina is an exception to this theory and has two histogens due to the presence of root cap position of root apex is sub terminal. Hence the maximum growth of root takes place behind the apex.
So, the correct answer is 'Two'
Multiple choice evs identifying the plants absorption of water from the soil root system the root system

Lateral roots are arises from

  1. Pericycle

  2. Cortex

  3. Pith

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

The pericycle is a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants. Although, it is composed of non-vascular parenchyma cells, it is still considered part of the vascular cylinder because it arises from the procambium as do the vascular tissues it surrounds. In eudicots, it also has the capacity to produce lateral roots. Branch roots arise from this primary meristem tissue. In plants undergoing secondary growth, the pericycle contributes to the vascular cambium often diverging into a cork cambium. Cortex, pith and endodermis does not gives rise to lateral roots.
Thus, the correct answer is option A.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

In roots, lateral branches grow from

  1. Epiblema

  2. Pericycle

  3. Cortex

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

The pericycle is a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants. Although, it is composed of non-vascular parenchyma cells, it is still considered part of the vascular cylinder because it arises from the procambium as do the vascular tissues it surrounds. In eudicots, it also has the capacity to produce lateral roots. Branch roots arise from this primary meristem tissue. In plants undergoing secondary growth, the pericycle contributes to the vascular cambium often diverging into a cork cambium. Thus, correct answer is option B.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

Quiescent centre is present in

  1. Shoot apex

  2. Root apex

  3. Both A and B

  4. Meristematic tissue
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The root apical meristem is present as the tip of the main root and has a biconvex quiescent centre in its centre which is characterized by the presence of inactive cells with less number of cell organelles and low synthesis of DNA, RNA and protein caused by the low frequency of cell division, mitosis. It is termed as a quiescent centre and serves as reserve meristem and is most apparent in actively growing roots but disappears during the dormant phase, carbohydrate starvation or root cap removal. Meristematic tissues have compactly arranged thin-walled cells with dense cytoplasm and large nucleus that produce new cells, they have high DNA, RNA and protein content. Shoot apex has apical bud which is involved in active growth.
Thus, the correct answer is option B.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

Quiescent centre is found in

  1. Leaf tip

  2. Shoot tip

  3. Root tip

  4. Flower
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The root apical meristem is present as the tip of main root and has a quiescent centre in its centre which is characterized by low frequency of cell division, mitosis, and thus, low synthesis of DNA, RNA and protein. The quiescent centre serves as reserve meristem and is most apparent in actively growing roots but disappears during dormant phase, carbohydrate starvation or root cap removal. Shoot apex has apical meristem in terminal position and hence, no quiescent centre. Leaf tip is permanent tissue derived from shoot apical meristem. Flower is defined as condensed shoot specialised for reproduction wherein shoot apical meristem is modified into flower meristem by the process of specialization of leaves into floral appendages it does not have quiescent centre.
Thus, the correct answer is option C.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

Quiescent centre is found on

  1. Root tip

  2. Shoot tip

  3. Floral tip

  4. Leaf tip
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The quiescent centre (QC) is a small group of cells with low mitotic activity. QC's are to be found at the tips of growing roots, in the root meristem and are typically surrounded by groups of initial cells. Through rounds of cell division, these initial cells give rise to the various tissues of the root and so there are usually vascular initials, pericycle initials, cortex initials etc. It is thought that the QC sends out signals to these initial cells to ensure that they remain in an initial state and keep dividing to produce whatever tissue they are responsible for. So, quiescent centre is found in root tips and not in shoot tip, floral tip or leaf tip. 
Thus, the correct answer is option A.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

The name of the sheath that covers root apex is

  1. Root hairs

  2. Parent roots

  3. Calyptra

  4. Root cap
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The sheath that covers root apex and is found at the tip of the root is called root cap. It protects the delicate growing root tip from damage as it goes through the soil. It consists of meristematic tissues and is the site where new root cells are dividing leading to root elongation. 
So, the correct answer is 'Root cap'
Multiple choice evs identifying the plants absorption of water from the soil root system the root system

Lignification is associated with

  1. Xylem

  2. Phloem

  3. Parenchyma

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

Lignification is associated with xylem. The lignin strengthens the walls of the xylem and the spirals provide flexibility. The advantages of lignification are :

1. Strengthens/thickens the wall
2. Waterproofing
3. Improving adhesion of water molecules
4. Spiral pattern provides flexibility/stretching/movement
5. Prevents collapse of xylem
6. Water under tension/at low pressure/negative pressure
7. Reduces lateral loss of water through wall
8. Increases capillarity
9. Prevents stem breaking

So, the correct option is 'Xylem'.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

There is maximum growth in root

  1. In the dark

  2. In the light

  3. At the root apex

  4. Just behind the root apex
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The region of fastest growth is behind the root tip because it consists meristematic cell that has the ability to divide. It is 4-8 mm long portion behind the tip. This region is called as root elongation region.

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

In a longitudinal section of a root, starting from the tip upward, the four zones occur in the following order.

  1. Cell division, cell enlargement, cell maturation, root cap

  2. Cell division, cell maturation, cell enlargement, root cap

  3. Root cap, cell division, cell enlargement, cell maturation

  4. Root cap, cell division, cell maturation, cell enlargement
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The four zones from the root tip are root cap, cell division, cell enlargement, cell maturation. Each zone has primary meristematic tissues with different functions. Root cap has parenchyma at tip. Zone of cell division has apical meristem, where the cells divide every 12-36 hours. Zone of elongation or enlargement, where cells get longer. Zone of maturation, which become specific cell types like epidermal cells and cortex.

So, the correct answer is 'Root cap, cell division, cell enlargement, cell maturation'

Multiple choice evs identifying the plants absorption of water from the soil root system the root system

In Monotropa, the special type of root which absorbs nourishment is the 

  1. Haustoria

  2. Mycorrhizal root

  3. Clinging root

  4. Adventitious root
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

  1. Haustoria is the specialized structure present in parasitic  plant or fungus that absorbs water and nutrients. For example, Cuscuta.
  2. Mycorrhizal roots are formed by the symbiotic association of plant roots and fungus and helps in nutrient absorption. For example, Monotropa.
  3. Clinging roots are many short branch like adventitious roots arise from nodes. For example, Piper betel.
  4. Adventitious roots are the roots that develop from any part of plant other than radicle. For example, banyan tree
So the correct option is 'Mycorrhizal root'.