Tag: plant hormones

Questions Related to plant hormones

Which of the following plant hormones reduces transpiration rate by inducing stomatal closure

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Ethylene

  2. Gibberellin

  3. ABA

  4. Cytokinin

Show answer
Correct Option: C
Explanation:

ABA (abscisic acid) is a plant hormone. It is also called as stress hormone as its concentration increases during stress condition. During adverse environmental conditions like drought, it induces stomatal closure. This results in reduced transpiration rate during water stress condition.

Thus, the correct answer is option C.

Consider the following statements.
a. Copper is present in Cytochrome oxidase
b. Pantothenic acid is the precursor of Coenzyme A
c. Thiamine pyrophosphate is the prosthetic group in decarboxylases
d. Zinc is present in RNA and DNA polymerases
Which of these statements are correct?

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. $1$ and $2$

  2. $2, 3$ and $4$

  3. $1, 2, 3$ and $4$

  4. $1, 3$ and $4$

Show answer
Correct Option: A

Match List I with List II and select the correct answer.

List-I(Name of chemical substance) List-II(Chemical structure)
a. Indoleacetic acid $1$. Benzene
b. a-naphthalene acetic acid $2$. Circular
c. Indolepyruvic acid $3$. Chain
d. Indolebutyric acid $4$. Anoymous
biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

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

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

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

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

Show answer
Correct Option: A

Which one of the following is a synthetic cytokinin?

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Ethylene-diaminetetraacetic acid

  2. Carboboenzoxyglylalanine

  3. $6$-furfurylaminopurine

  4. $2, 4$-$5$ trichlorophenoxypropionic acid

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Correct Option: A

Which of the following is both a growth promoter as well as a growth inhibitor?

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Auxin

  2. Gibberellins acid

  3. ABA

  4. Ethylene

Show answer
Correct Option: D
Explanation:

Ethylene is considered as the growth hormone which regulates promoter and inhibitor as it is used to make the fruit ripen, breaks bud dormancy, initiates flowering. It acts as inhibitor as it retards the mitotic division in root and shoot meristem and also for axillary buds.

So the correct option is 'Ethylene'.

Choose the correct answer from the alternatives given.
Closing of stomata are induced by:

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. axing

  2. boxing

  3. abscise acid

  4. indole 3-acetic acid

Show answer
Correct Option: C
Explanation:

ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses.

So, the correct option is 'abscisic acid'. 

Physiological function not affected by ABA is

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Abscission

  2. Senescence

  3. Dormancy

  4. Flowering

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Correct Option: A

Hormone responsible for ageing is ____________.

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. GA

  2. IAA

  3. Ethylene

  4. Cytokinin

Show answer
Correct Option: C
Explanation:

The plant hormone ethylene is growth inhibitor and is released in plant organs that are to undergo ripening or senescence. Ethylene triggers climacteric ripening of the fruit and induces insensitivity of senescent organs to auxins due to which the nutrients are channelized to other growing parts of the plant resulting in withering away of the plant part.

So, the correct answer is 'Ethylene'

Select the mismatched pair.

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. Gibberellic acid - Increases yield of sugarcane

  2. Cytokinin - Promotes apical dominance

  3. Ethylene - Sprouting of potato tuber

  4. Abscisic acid - Inhibits seed germination

Show answer
Correct Option: B
Explanation:

Gibberellic acid increases the yield of sugarcane crop. Cytokinins inhibit apical dominance and act antagonistically to auxins which promote apical dominance. Rhizomes, corms, tubers, seeds (e.g., peanut) and other storage organs can be made to sprout early by exposing them to ethylene. Abscisic acid is a plant growth inhibitor, which inhibits seed germination.

The affect of apical dominance can be overcome by which of the following hormone?

biology plant growth other plant hormones cytokinins, ethylene and abscisic acid plant hormones

  1. IAA

  2. Ethylene

  3. Gibberellin

  4. Cytokinin

Show answer
Correct Option: D
Explanation:

Presence of cytokinin in an area causes preferential movement of nutrients towards it. When applied to lateral buds, they help in their growth despite the presence of apical bud. They thus act antagonistically to auxin which promotes apical dominance. Therefore cytokinin can overcome apical dominance, caused by auxins.