Tag: chemical coordination in plants

Questions Related to chemical coordination in plants

Read the given statements and identify the plant hormones X, Y and Z.
(i) Hormone Y suppresses flowering in mango and also promotes rapid internode/petiole elongation in deep water rice plants and hence helping leaves or upper part of shoot to remain above water.
(ii) Hormone X promotes root growth and root hair formation.
(ii) Hormone Z inhibits the seed germination, increases the tolerance of plant to various stresses, play important role in seed development maturation and dormancy.

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Y-ABA, X-Auxin, Z-GA

  2. Y-$C _2H _4$, X-Auxin, Z-GA

  3. Y-Auxin, X-$C _2H _4$, Z-GA

  4. Y-GA, X-auxin, Z-ABA

Show answer
Correct Option: D
Explanation:

i) Gibberilic Acid (GA) suppresses flowering in mango, GA$ _3$, it is applied periodically to mango plants in their 1-4 yrs of growth to inhibit flowering and promote vegetative growth. GA plays a role in internode elongation in submerged parts of the rice plant.

Auxin along with cytokinin promotes root growth and root hair formation.
ABA is a stress hormones, it protects the plant from unfavorable environmental conditions, by preventing seed germination (due to oxygen deficit, water stress etc).
So, the correct answer is 'Y-GA, X-auxin, Z-ABA'

Read the given statements and select the option that is/are incorrect ones.


(i) Cytokinin is primarily concerned with cell division.
(ii) $C _2H _4$ breaks seed and bud dormancy.
(iii) ABA stimulates the opening of stomata.
(iv) $C _2H _4$ initiates germination in peanut seeds, sprouting of potato tubers.
(v) ABA is synergistic to GA.

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. (i), (ii) and (iv)

  2. (iii) and (ii)

  3. (iii) and (v)

  4. (iv) and (v)

Show answer
Correct Option: C
Explanation:

ABA is regarded as the stress hormone or a growth inhibitor. In conditions of water stress ABA initiates closure of stomata to prevent water loss through transpiration. It is antagonistic to GA as the latter promotes seed germination,  while ABA prevents seed germination.

So, the correct answer is ' (iii) and (v)'

Match the plant hormones listed in column I with their major role listed in column II and select the corret option from the codes given below.

Column I Column II
(A) Auxin (i) Fruit ripening
(B) Cytokinin (ii) Phototropism
(C) Abscisic acid (iii) Suppression of cell division
(D) Ethylene (iv) Stomatal opening and closing
(v) Growth of lateral buds


biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. A - (v), B - (iii), C - (iv), D - (ii)

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

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

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

Show answer
Correct Option: C
Explanation:

(A) Auxin - (ii) Phototropism

(B) Cytokinin - (v) Growth of lateral buds

(C) Abscisic acid - (iv) Stomatal opening and closing

(D) Ethylene - (i) Fruit ripening

So, the correct answer is 'A - (ii), B - (v), C - (iv), D - (i)'.

In plant tissue culture experiments, high auxin to cytokinin ratio favours .............. development and high cytokinin to auxin ratio favours .............. development.

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Root, shoot

  2. Shoot, root

  3. Root, root

  4. Shoot, shoot

Show answer
Correct Option: A
Explanation:
Callus is an unorganized, undifferentiated mass of diving cells formed during tissue culture which requires both auxins and cytokinins for its growth and differentiation. In callus, shoot regeneration is promoted by a cytokinin, such as BAP (Benzylaminopurine) and root regeneration is promoted by an auxin, such as NAA (Naphthalene acetic acid). Thus, shoot and root regenerations in callus are controlled by auxin-cytokinin balance. Usually, an excess of auxins promote root regeneration and that of cytokinins promote shoot regeneration.
So the correct option is 'root, shoot'.

Small cut pieces of soft stems are placed in growth medium with following plant hormone. Which combination of plant hormones will show the slowest growth? 

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Auxin+Cytokinin

  2. Gibberellins+Auxin

  3. Gibberellins+Cytokinin

  4. Abscisic Acid+Auxin

Show answer
Correct Option: D
Explanation:

Abscisic acid is growth inhibiting hormone whereas auxin, gibberellin and cytokinin are growth promoting hormones. Options A,B, and C include all growth promoting hormones whereas option D includes both growth promoting and growth inhibiting hormones. Therefore, this combination of hormones will show slowest growth.

So option D is the correct answer.

Cytokinin and auxin are antagonistic in which of the following function?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Cell division

  2. Phototropism

  3. Apical dominance

  4. Geotropism

Show answer
Correct Option: C
Explanation:
  • The main function of Auxin is to promote stem elongation and inhibition of growth of lateral buds to maintain apical dominance.
  • It is produced in the stem tips, buds and root tips to promote growth and it also helps to repair wounds in plants.
  • The function of cytokinins is to increase the cell division by stimulating the process of mitosis which helps in plant growth and formation of shoots and buds.
  • Cytokinins promote sprouting of lateral buds and overcome apical dominance.
  • Cytokinin and auxin are antagonistic for apical dominance.
  • So the correct answer is 'Apical dominance'.

Rooting plant hormone is 

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. $IBA$

  2. $2, 4-D$

  3. $2,4,5-T$

  4. $NAA$

Show answer
Correct Option: A

I. ACTH
II.GH
III.MSH
IV.FSH
V.LH
VI.Oxytocin
Which of the above hormones are polypeptide or proteinaceous in nature?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. I,II,III and IV

  2. III,IV ,V and VI

  3. III,IV ,V and VI

  4. I,II,III and VI

Show answer
Correct Option: A

Which of the following plant hormones is not acidic in nature?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Gibberellin

  2. Auxin

  3. Cytokinin

  4. ABA

Show answer
Correct Option: A

Which of the following statement/s is/are incorrect?

biology life processes: control and coordination control and coordination in plants growth in plants chemical coordination in plants animal senses sense organs in animals sense organs in humans

  1. Auxin is synthesized at shoo tip

  2. Due to auxin, plant appears to bend towards dark

  3. Gibberellins help in the growth of stem

  4. cell division is promoted by cytokinin

Show answer
Correct Option: A