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Shoot and root apex - class-XI

Description: shoot and root apex
Number of Questions: 39
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Tags: biology anatomy of flowering plants botany tissue and tissue system plant tissues - internal morphology and anatomy
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Match column I with column II and select the correct option from the given codes.

   Column  I     Column II
 A.  Vegetative buds  i.  Buds develop in axils of leaves
 B.  Floral buds  ii.  Buds produce leafy shoots 
 C.  Axillary buds  iii.  Reproductive buds that produce flowers
 D.  Accessory  iv  Additional buds borne at leaf bases
  1. (A) - (ii), (B) - (iii), (C) - (i), (D) - (iv)

  2. (A) - (iii), (B) - (ii), (C) - (i), (D) - (iv)

  3. (A) - (iv), (B) - (iii), (C) - (ii), (D) - (i)

  4. (A) - (i), (B) - (ii), (C) - (iv), (D) - (iii)


Correct Option: A
Explanation:

Bud is a condensed rudimentary shoot. Such buds developed into leafy shoots.

  • Axillary buds: originate from the axils of leaves.
  • Vegetative buds: Buds that give rise to new shoots and leaves. Presence of such bud indicates the regrowth of the plant.
  • Floral bud: It is swelling or formation of a premature flower bloom. This bud will eventually produce a flower.
  • Accessory bud:  A bud growing near and in addition to a axillary bud.
  • So, the correct answer is " (A)- (ii),(B)- (iii), (C) - (i), (D) - ( iv).

Flower is always solitary when:

  1. Shoot bud transforms into flower

  2. Shoot tip transforms into flower

  3. Lateral shoot transforms into flower

  4. Horizontal shoot transform into flower


Correct Option: B
Explanation:

Option (B) Shoot tip transform into flower.

Shoot tip meristem gets to stop to divide as the shoot cells, and flower formation takes place.
Solitary means a single flower.
When the tip of the shoots is gets transformed into a flower only one single flower will be formed.
Because single tip of shoot have ability to carry only single flower.

Aecessory buds are-

  1. Axillary buds

  2. Adventitious buds

  3. Terminal buds

  4. Not true buds


Correct Option: A

The cells of root apex and shoot apex?

  1. Are poor in cytoplasmic content

  2. Possess small and inconspicuous nuclei

  3. Are with abundant plasmodesmatal connections

  4. Possess cell wall which is always secondary in nature


Correct Option: A

Bud associated with the underground stem of potatoes is?

  1. Axillary

  2. Apical

  3. Adventitious

  4. Internodal


Correct Option: A

If there is more than one tunica layer in a stern apex. 

Which among the following is most likely to happen?

  1. All the layers will develop into epidermal cells

  2. Only the outer layer will develop into epidermal cells

  3. All the layers will develop into cortex

  4. Inner layer develops into cortex


Correct Option: B
Explanation:

Even, if there is more than one tunica layer in the stem apex, only the outer layer will develop into the epidermal cells. The stem has three simple cell types, i.e. the parenchyma, collenchyma and sclerenchyma cells which are responsible for the metabolic functions, repairing and healing wounds and storing starch.

The correct option is B.

The organization of the shoot apex into tunica and corpus is determined largely on the basis of _______________.

  1. Rate of shoot tip growth

  2. Rate of cell division

  3. Planes of cell division

  4. Regions of meristematic activity


Correct Option: B
Explanation:

Schmidt has postulated tunica- corpus theory on the basis of studies of shoot apices of angiosperm. This theory is concerned with planes of cell division in the apex. In contrast to apical cell theory, the tunica-corpus theory is applicable only to shoot apex and not to root. There are three types of meristematic tissues like apical (at the tips), intercalary (in the middle) and third as lateral (at the sides).

Schmidt distinguished two tissue zones in the shoot apex and termed as tunica and corpus.

The correct answer is B.

Heaping of earth around base of stem in Potato is meant for.

  1. Preventing exposure of roots

  2. Providing extra support to delicate stem

  3. Inducing development of more auxiliary shoots

  4. Making more water available


Correct Option: C

Assertion (A): Lateral buds close to the shoot apex remain dormant while those some distance below below the apical meristem develop into shoots.

Reason (R): Apical shoot meristems and young leaves are the centres of lAA synthests.

  1. Both A and Rare individually true and R is the correct explanation of A

  2. Both A and Rare individually true and R is not the correct explanation of A

  3. A is true but R is false

  4. A is false but R is true Assertion


Correct Option: A

The shoot branching depends upon the development of axillary buds, but many of the buds in axillary position never grow out due to the _____________________.

  1. Inhibitory factor present in the axillary bud

  2. Inhibitory factor present in the apical bud

  3. Interaction of factors present in both the axillary & apical bud

  4. Ibhibition under genetic control


Correct Option: A

Meristematic tissue which is found on apical part of root is called ______________.

  1. Axillary bud

  2. Lateral bud

  3. Quiescent centre

  4. None of these


Correct Option: A

What is the eye of potato ?

  1. Axillary bud

  2. Accessory bud

  3. Adventitious bud

  4. Apical bud


Correct Option: A

A simple leaf can be differentiated from the pinnae of a compound leaf on the basis of presence or absence of

  1. number of pinnae

  2. shape of lamina

  3. axillary bud

  4. lateral buds


Correct Option: C
Explanation:

A simple leaf can be differentiated from the pinnae of a compound leaf on the basis of the presence or absence of 'axillary bud'.

Eye of Potato is

  1. Apical bud

  2. Axillary bud

  3. Accessory bud

  4. Adventitious bud


Correct Option: B
Explanation:

Actually there are generally three buds in the region of eye. Only one is axillary. The other two are accessory. 

Histogen theory is more applicable for

  1. Root apex

  2. Meristematic tissue

  3. Both (A) and (B)

  4. None of the above


Correct Option: A
Explanation:

The histogen theory was given by Hanstein (1870). The three principal tissues of the root vascular cylinder, cortex and epidermis originate from three groups of initial cells or histogens, in the apical meristem plerome, periblem and dermatogen respectively. A fourth histogen, the calyptrogen, produces the root cap.    
Thus, the correct answer is option A.    

Root cap of the embryo develops from:

  1. Basal cell

  2. Apical cell

  3. Hypophysis

  4. Hypocotyl


Correct Option: C
Explanation:

 The formation of the root apex involves derivatives of both the basal and apical cells of the two-cell embryo, the hypophyseal region derived from the topmost cell of the suspensor is incorporated into the embryo proper, giving rise to part of the root cap.

So, the correct option is 'Hypophysis'.

Which of the following correctly includes homologous organs?

  1. Roots of sweet potato and stem of potato

  2. Wings of moth and pigeon

  3. Forelimbs of salamander and hindlimbs

  4. Brain of humans and pheretima


Correct Option: A

Histogen is a

  1. Promeristem derivative destined to produce specific areas

  2. Intercalary meristem meant for forming specific tissue

  3. Derivative of lateral meristem

  4. Secondary meristem specialised to produce specific structures


Correct Option: A
Explanation:
  • Promeristem is a group of young meristematic cells in its early embryonic stage from which other meristems are derived. 
  • Apical meristems are derived from promeristem and are present below the promeristem at shoot tip and root tip.
  • The shoot apical meristem (SAM) consists of three distinct meristematic zones called the histogens.
  • These histogens are present at the growing tips of a stem or a root.
  • These tips consist of three histogens and each of these histogens gives rise to tissues which are different from one another- dermatogen, periblem, plerome (principle tissues)
  • The dermatogen or the outer layer gives rise to the epidermis, periblem or middle layer gives rise to the cortex as well as the epidermis, plerome or the inner layer gives rise to vascular tissues.
  • So, the correct answer is 'Promeristem derivative destined to produce specific areas'.

Naphthalene acetic acid is applied on a apple tree. The tree will produce?

  1. More dwarf shoots and more apples

  2. More long branches and more apples

  3. Long root for deep penetration within soil

  4. Less side branches and more apical growth


Correct Option: A

The persisting embryonic tissue in the plant body is called?

  1. Permanent tissues

  2. Parenchyma

  3. Meristem

  4. Xylem


Correct Option: C
Explanation:

Promeristem is the area of new development in a plant body where the establishment of new organs or parts of organs is started. Some of the time, it is additionally called primordial meristem, meristem and embryonic meristem.

So, the correct answer is 'Meristem'

The term quiescent centre or zone was proposed by

  1. Schmidt

  2. Foster

  3. Clowes

  4. Nageli


Correct Option: C
Explanation:
  • The quiescent centre is that part of the root-promeristems of higher plants 
  • They may consist of four cells (minimum) or can go up to 600 cells which show very low mitotic activity.
  • In closed meristem, QC is hemispherical in shape whereas, in open meristem it is disc-shaped.
  • The QC is unusual in the centre of shoots.
  • Frederick Albert Lionel Clowes was a British biologist.
  • He proposed the term Quiescent centre or cytogenerative centre which represents the region of an apical meristem of the root where cell division is very slow.
  • So, the correct answer is 'Clowes'

Cells of quiescent centre are characterized by

  1. Dense cytoplasm and prominent nuclei

  2. Light cytoplasm and small nuclei

  3. Dividing regularly to add to the corpus

  4. Dividing regularly to add to tunica


Correct Option: B
Explanation:
  • The quiescent centre is that part of the root-promeristems that contains the initials of epidermis, cortex and stele.
  • These cells divide less frequently as they are inactive and are present at the pole of cortex and stele.
  • The cells with QC have small dictyosomes, nuclei and nucleoli with little cytoplasm.
  • These cells also have little endoplasmic reticulum, mitochondria and contain low concentrations of RNA, DNA and protein than the other cells of the root apex.
  • So, the correct answer is 'Light cytoplasm and small nuclei'.

Histogen tissues are classified on the basis of _________.

  1. Plane of division

  2. Type of cells they form

  3. Position

  4. Origin


Correct Option: B
Explanation:
  • The shoot apical meristem (SAM) form three distinct meristematic zones called the histogens.
  • These histogens are present at the growing tips of a stem or a root.
  • These tips consist of three histogens based on the type of cells they form.
  • Each of these histogens gives rise to tissues which are different from one another- dermatogen, periblem, plerome (principle tissues)
  • The dermatogen or the outer layer gives rise to the epidermis, periblem or middle layer gives rise to the cortex as well as the endodermis, plerome or the inner layer gives rise to vascular tissues.
  • This is called histogen theory which was proposed by Hanstein in 1870.
  • So, the correct answer is 'Type of cells they form'

Quiescent centre is the zone of

  1. Least mitotic activity in the root apex

  2. Least mitotic activity in the shoot apex

  3. Maximum mitotic activity in the root apex

  4. Maximum mitotic activity in the shoot apex


Correct Option: A
Explanation:

A zone of inactive cells is present in the central part of the root apex called quiescent centre.

Reproductive shoot apex is

  1. Conical or dome shaped

  2. Broad

  3. Broad and flat

  4. Narrow


Correct Option: C
Explanation:
  • Reproductive shoot apex- At the time of flowering, the vegetative shoot apex transforms into reproductive shoot apex.
  • The summit zone of reproductive shoot apex is active as the rate of cell division is greater and it forms stamens and carpels.
  • Whereas, the flank zone is less active in reproductive shoot apex and it forms sepals and petals.
  • The Reproductive shoot apex is Broad and flat.
  • So, the correct answer is 'Broad and flat'.

Histogen theory was proposed by

  1. Bailey

  2. Haberlandt

  3. Hanstein

  4. Schmidt


Correct Option: C
Explanation:

The histogen theory was given by Hanstein (1870), According to this, there are 3 groups of initials in the shoot apex. According to Hanstein, the three principal tissues of the root; vascular cylinder, cortex and epidermis originate from three groups of initial cells or histogens, in the apical meristem plerome, periblem and dermatogen respectively. A fourth histogen, the calyptrogen produces the root cap.
Therefore, the correct answer is option C.  

Tunica corpus theory is connected with

  1. Root apex

  2. Root cap

  3. Shoot apex

  4. Secondary growth


Correct Option: C
Explanation:
  • The Tunica-corpus theory explains the planes of cell division in the shoot apex.
  • It was proposed by Schmidt in 1924.
  • It was proposed on the basis of the study of shoot apex.
  • This theory is applicable only to shoot apex and not to root. 
  • This theory divides the region (shoot apex) into two tissue zones known as tunica and corpus.
  • The shoot apex is composed of two layers of cells of tunica and corpus  (layer L1, L2 and L3 to denote the outer layer of tunica, the inner layer of tunica and corpus respectively).
  • The plasmodesmata connections exist between the cells of tunica and corpus.
  • So, the correct answer is 'Shoot apex'

According to histogen theory, epidermis is formed by

  1. Dermatogen

  2. Protoderm

  3. Periblem

  4. Plerome


Correct Option: A
Explanation:
  • The histogens at the shoot and root tip in plants as these are derived from the apical meristematic tissues according to the histogen theory given by Hanstein.
  • It consists of three distinct layers:-
  1. Dermatogen is the primary meristem that forms the outer most layer of a plant or a plant part and forms the epidermis.
  2. Periblem is a primary meristem which is located between the plerome and the dermatogen and it forms the cortex.
  3. Plerome is the primary meristem that forms the central core of a plant or plant part which gives rise to the stele (includes the vascular tissue, pith and pericycle).
  • The part of plerome from which vascular tissues are formed is called procambium.
  • So the correct answer is 'Dermatogen'

Concept envisaging three zones of cells in root and stem apices is

  1. Histogen theory

  2. Tunica corpus theory

  3. Meristem theory

  4. Dermatogen theory


Correct Option: A
Explanation:
  • The shoot apical meristem (SAM) consists of three distinct meristematic zones called the Histogens.
  • This is called histogen theory of tissues which was proposed by Hanstein in 1870 explains the activity of both the root and shoot apical meristem.
  • These histogens are present at the growing tips of a stem or a root.
  • These tips consist of three histogens and each of these histogens gives rise to tissues which are different from one another
1) Dermatogen is the primary meristem that forms the outer most layer of a plant or a plant part and forms the epidermis.
2) Periblem is a primary meristem which is located between the plerome and the dermatogen and it forms the cortex.
3) Plerome is the primary meristem that forms the central core of a plant or plant part which gives rise to the stele (includes the vascular tissue, pith and pericycle).
  • The part of plerome from which vascular tissues are formed is called procambium.
So, the correct answer is 'Histogen theory'

In the root apex, that meristem from which the root cap developsindependently of all other initials of the apical meristem is known as _______________.

  1. Calyptrogen

  2. Casparian strip

  3. Columella

  4. Corpus


Correct Option: A

Histogen theory was proposed by

  1. Nageli

  2. Schmidt

  3. Hanstein

  4. Wolf


Correct Option: C
Explanation:
  • The shoot apical meristems located at the shoot tip in plants are derived from the apical meristematic tissues according to the histogen theory given by Hanstein in 1868.
  • It consists of three distinct layers:-
1) Dermatogen is the primary meristem that forms the outer most layer of a plant or a plant part and forms the epidermis.
2) Periblem is a primary meristem which is located between the plerome and the dermatogen and it forms the cortex.
3) Plerome is the primary meristem that forms the central core of a plant or plant part which gives rise to the stele (includes the vascular tissue, pith and pericycle).
  • The part of plerome from which vascular tissues are formed is called procambium.
So, the correct answer is 'Hanstein'

According to the concept of waiting meristem, the active region of shoot apex is?

  1. Anneau initial

  2. Meristeme medullaire

  3. Promeristeme sporogene

  4. Promeristeme receptaculaire


Correct Option: A

Match List-I(Region) with List-II(Contribution to) and select the correct answer using the codes given the lists.

List-I(Region) List-II(Contribution)
a. Apical cells of $2$-celled embryo $1$. Emergence of cotyledons
b. Basal cells of $2$-celled embryo $2$. Differentiation of root and shoot
c. Torpedo stage embryo $3$. Root apex and suspensor
d. Globular embryo $4$. Bulk of the embryo proper
  1. A-$1$, B-$2$, C-$3$, D-$4$

  2. A-$1$, B-$3$, C-$2$, D-$4$

  3. A-$4$, B-$2$, C-$4$, D-$1$

  4. A-$4$, B-$3$, C-$2$, D-$1$


Correct Option: A

Consider the following statements.
a. In the roots with endomycorrhizal association, the fungal hyphae penetrate the root cortex and pass through the casparian strip to enter vascular tissue.
b. The globin part of leghemoglobin in nitrogen-fixing root nodules is encoded by the bacterium whereas heme group is synthesized by the host plant.
Which of the statements given is/are correct?

  1. $1$ only

  2. $2$ only

  3. Both $1$ and $2$

  4. Neither $1$ nor $2$


Correct Option: A

Choose the correct answers from the alternatives given.
Which of the following functions is not shared by both the root system and the shoot system of a plant?

  1. Absorb water

  2. Transport water

  3. Transport inorganic nutrients

  4. Transport organic nutrients


Correct Option: A
Explanation:

The root system forms the underground system of the plant that absorbs water from the soil along with various organic and inorganic nutrients. It exerts the root pressure due to which the absorbed water is transported to the shoot system.

The shoot system forms the upper part of the plant part. It transports the absorbed water and nutrients to different plant parts.
Hence, the correct answer is 'Absorb water'.

Which one of the following histogens is present in the roots but Not in the shoots?

  1. Calyptrogen

  2. Dermatogen

  3. Periblem

  4. Plerome


Correct Option: A
The cells of the quiescent centre are characterised by
  1. having dense cytoplasm and prominent nuclei

  2. having light cytoplasm and small nuclei

  3. dividing regularly to add to the corpus

  4. dividing regularly to add to tunica


Correct Option: B
Explanation:

The cells of the quiescent centre are characterised by 'light cytoplasm and small nuclei'.

Choose the correct answers from the alternatives given :
Plant roots function to

  1. anchor the plant

  2. store the products of photosynthesis

  3. produce hormones that stimulate stem growth

  4. all of the above


Correct Option: D
Explanation:

Root is the most important organ of a plant which generally lies below the soil in the vascular plants.

The main functions of the root are:
a. It anchors the plants in soil and thus provides mechanical support to plants to stand upright.
b. Photosynthesis products are usually stored in roots. eg. Raddish, carrots etc.
c. Roots synthesize certain hormone that helps in the growth of the plant.

So the correct answer is "All of the above"

Choose the correct answers from the alternatives given.
When a leaf trace extends from a vascular bundle in a dicot stem, what would be the arrangement of vascular tissues in the veins of the leaf

  1. Xylem would be on top and the phloem on the bottom

  2. Phloem would be on top and the xylem on the bottom

  3. Xylem would encircle the phloem

  4. Phloem would encircle the xylem


Correct Option: A
Explanation:

Vascular bundles are scattered in the spongy parenchyma. These can be seen in the veins and the midrib of the leaves. The dicot leaves possess reticulate venation in which veins form a network. The xylem forms the top layer and phloem is present at the bottom in the arrangement of the vascular tissues. The veins vary in thickness in the reticulate venation.

Hence, the correct answer is 'Xylem would be on top and the phloem on the bottom'.

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