Tag: growth in plants

Questions Related to growth in plants

Match the following.

A. IAA (i) Herring sperm DNA
B. ABA (ii) Bolting
C. Ethylene (iii) Stomatal closure
D. GA (iv) Weed-free lawns
E. Cytokinins (v) Ripening of fruits
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-(iv), B-(iii), C-(v), D-(ii), E-(i)

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

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

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

Show answer
Correct Option: A
Explanation:

IAA is an auxin but has potential role of herbicide and weedicide. ABA is stress inducing plant growth regular. It can induce closure of stomata, Ethylene on other hand increases climactic rate and hence used for fruit ripening, GA or gibberlic acid are known to cause bolting in crucifers. Cytokinins were first isolated from Herring sperm DNA.

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

Which of the following is a plant hormone?

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. Insulin

  2. Thyroxin

  3. Oestrogen

  4. Cytokinin

Show answer
Correct Option: D
Explanation:

Insulin is secreted by Islets of Langerhans of the pancreas and serves to lower the blood glucose level by stimulating the uptake of glucose by cells, specifically muscle cells, liver cells and adipose tissues cells. 

Thyroxine is a thyroid hormone which targets all tissues and stimulates metabolic rate, growth and development. 
Oestrogen is the female sex hormone secreted by developing follicles in the ovary. It serves to stimulate the growth of the uterus and the vagina, is necessary for egg maturation as well as for the development of the secondary sex characteristics in females. Thus, options A, B and C are incorrect as these hormones are animal hormones. 
Cytokinins are the plant growth hormones that regulate the cell division in root and shoot of the plant both in vivo and in-vitro.
So, the correct answer is 'Cytokinin' 

Which one is paired incorrectly?

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 - Isolated from human urine

  2. Zeatin - Isolated from corn kernels and coconut milk

  3. Gibberellins - Isolated from fungus G. fujikori

  4. Abscisic acid - Isolated from ripened oranges

Show answer
Correct Option: D
Explanation:

Kogl et al. (1931) isolated auxin from human urine called heteroauxin which was identified as indole-3-acetic acid (IAA).
Zeatin is a cytokinin-like substance isolated and crystallised by Letham (1963-65) from milky endosperm of corn (Zea mays). It also occurs in coconut milk.
Yabuta and Sumiki (1938) isolated a chemical substance from the cultural filtrate of fungus Gibberella fujikuroi in crystalline form and named it gibberellic acid.
Cousins (1910) found that ripe oranges produced a volatile substance that hastened ripening of unriped bananas nearby. With the help of gas chromatography, it was found that the ripening causing volatile substance was ethylene.
So, the correct answer is 'Abscisic acid - Isolated from ripened oranges'.

To speed up the malting process in brewing industry the growth hormone used 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. auxin

  2. gibberellin

  3. kinetin

  4. ethylene.

Show answer
Correct Option: B
Explanation:

Gibberellins are used to speed up the malting process in brewing industry. They increase the yield of malt from barley grains.

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'.