Tag: plant hormones

Questions Related to plant hormones

Hormone that is associated with retaining the chloroplast chlorophyll is ?

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. Auxin

  2. ABA

  3. Cytokinin

  4. Gibberelins

Show answer
Correct Option: C
Explanation:

Cytokinin is a plant hormone which acts as plant growth regulator. It is associated with retaining the chloroplast chlorophyll in the leaves. The cytokinin has anti-senescence effect on the plant. It delays the senescence of the leaves and prevents the destruction of chloroplast.

Thus, the correct answer is option C.

Which plant hormone promotes cell division?

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. Gibberellins

  2. Cytokinin

  3. Ethylene

  4. Auxins

Show answer
Correct Option: B
Explanation:
  • Cytokinins(CK) are a class of plant growth hormones that promote cell division, or cytokinesis in plants roots and shoots. For example, Kinetin and benzyl-aminopurine.
  • They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and leaf senescence.
  • Hence the plant hormone promotes cell division is Cytokinin.
  • So, the correct answer is 'Cytokinin'.

Cytokinins helps to produce all except.

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. New leaves

  2. Chloroplast in leaves

  3. Lateral short growth and adventitious shoot foration

  4. Rooting on cut stem

Show answer
Correct Option: D
Explanation:

Phytohormone concerned in the cell division is called cytokinins. It is involved in the formation of chloroplast in leaves, new leaves formation, lateral shoot growth and adventitious shoot formation.

So, the correct option is ‘rooting on cut stem’.

Choose the correct answer from the alternatives given.
Application of which of the following hormones prevents plant tissues from senescing or ageing?

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. Abscisic acid

  2. Auxin

  3. Cytokinin

  4. Ethylene

Show answer
Correct Option: C
Explanation:

Cytokinins help overcome apical dominance. They promote nutrient mobilization which helps in the delay of leaf senescence.

So, the correct option is 'Cytokinin'.

Choose the correct answer from the alternatives given.
A hormone that causes cell division and is found in coconut milk or in dividing root tissue is:

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. abscisic acid

  2. auxin

  3. cytokinin

  4. gibberelthi

Show answer
Correct Option: C
Explanation:

In the presence of auxin (but not in its absence) kinetin stimulated tobacco pith parenchyma tissue to proliferate in culture. Later, zeatin was identified as the first naturally occurring cytokinin in immature maize endosperm (Letham, 1973), and turns out to be the abundant cytokinin in coconut milk.

So, the correct option is 'cytokinin'.

Choose the correct answer from the alternatives given.
Cytokinins

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. are plant hormones that promote cell division

  2. are used in combination with auxin to produce plants from undifferentiated callose tissue.

  3. also work with oligosaccharins to effect tissue differentiation

  4. all of the above.

Show answer
Correct Option: D
Explanation:

It helps to produce new leaves, chloroplasts in leaves, lateral shoot growth and adventitious shoot formation. Cytokinins help overcome apical dominance. They promote nutrient mobilisation which helps in the delay of leaf senescence.

Natural cytokinins are synthesised in regions where rapid cell division occurs, for example, root apices, developing shoot buds, young fruits etc.
So, the correct option is 'all of the above'.

Cytokinins are mostly ____________.

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. glucosides

  2. phenolics

  3. amino purines

  4. organic acids.

Show answer
Correct Option: C
Explanation:

Cytokinins are plant growth hormones which are basic in nature, either amino purine or phenyl urea derivatives, that promote cytokinesis (= cell division) either alone or in conjunction with auxin. Kinetin, a synthetic cytokinin, is 6-furfuryl amino purine. Zeatin, a natural cytokinin, is 6-hydroxy 3-methyl trans 2-butenyl amino purine.

Select the pair that consists of plant growth promoters only.

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. Auxins and cytokinins

  2. Gibberellins and ABA

  3. Ethylene and ABA

  4. All of these

Show answer
Correct Option: A
Explanation:

Auxins and cytokinins are plant growth promoters, the roles played by auxin and cytokinin are as follows.

Auxins: Cell enlargement and longitudinal growth of root and shoot.
             Reactivation of cambium in the growth season, that is, responsible for secondary growth, promotes apical dominance and parthenocarpy, inhibits abcission.
Cytokinins: induces morphogenesis that is differentiation of cells into tissues and organs.delays senescence, breaks dormancy and promotes seed germination, enhances expression of a sexual characteristic- femaleness in some plants.
Auxin/cytokinin ratio influences root and shoot formation and growth
So, the correct answer is 'Auxins and cytokinins'

Which among the following is not a function of cytokinins?

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. Essential for Cytokinesis during cell division

  2. Delays the senescence of leaves

  3. Helps in fruit ripening

  4. Helps to overcome apical dominance

Show answer
Correct Option: C
Explanation:

Fruit ripening or climacteric fruit ripening is induced by ethylene in most of the fruits, and therefore is not a function of cytokinins.

So, the correct answer is 'Helps in fruit ripening'

Natural cytokinins are synthesized in regions where rapid cell division occurs. Such regions are

biology chemical coordination in plants cytokinins plant hormones plants and animal hormones

  1. Root apices

  2. Developing shoot buds

  3. Young fruits

  4. All of these.

Show answer
Correct Option: D
Explanation:
About 18 types of cytokinins have been discovered till now. Some of them are constituents of t RNAs. Roots are considered as the major source of cytokinin synthesis; from roots, the cytokinins pass upwardly through the xylem. Cytokinin synthesis also occurs in the areas where cell division takes place e.g., growing embryos and developing seeds, endosperm of seeds, young fruits, developing shoot buds, etc.
So the correct option is 'All of these'.