Tag: plant growth and development

Questions Related to plant growth and development

The hormones responsible for apical dominance is

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. IAA

  2. GA

  3. ABA

  4. Florigen

Show answer
Correct Option: A
Explanation:

Apical dominance is a phenomenon in which central stem is dominant and lateral branches are suppressed. It is due to plant hormones produced in the tip of the shoot. IAA, a type of auxin hormone is responsible for apical dominance and cytokinin hormone is responsible for breaking the apical dominance. 

So, the correct answer is 'IAA'

Apical dominance as found in higher plants is due to

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Photoperiodism

  2. Phototropism

  3. Hormones

  4. Enzymes

Show answer
Correct Option: C
Explanation:

Apical dominance is a phenomenon in which central stem is dominant and lateral stems are suppressed. It is due to plant hormones produced in the tip of the shoot. Auxin hormone is responsible for apical dominance and cytokinin hormone is responsible for breaking the apical dominance. 

Thus, the correct answer is option C.

Removal of apical bud results in

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Formation of new apical bud

  2. Elongation of main stem

  3. Death of plant

  4. Formation of lateral branching

Show answer
Correct Option: D
Explanation:

Apical dominance is a phenomenon in which central stem is dominant and lateral stems are suppressed. It is due to plant hormones produced in the tip of the shoot. Auxin hormone is responsible for apical dominance. When apical bud is removed, there is growth of lateral bud. This results in formation of lateral branching. This makes plant bushy.

Thus, the correct answer is option D.

Lateral axillary buds are not allowed to grow by

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Auxin

  2. Ethylene

  3. Gibberellin

  4. Cytokinin

Show answer
Correct Option: A
Explanation:

Apical dominance is a phenomenon in which central stem is dominant and lateral stems are suppressed. It is due to plant hormones auxin produced in the tip of the shoot. It promotes apical dominance and does not allow lateral axillar buds to grow. However, when tip of the shoot is cut, it promotes the growth of lateral axillary buds.

So, the correct answer is 'Auxin'

Auxins promote

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Apical dominance

  2. Cambial activity

  3. Cell growth

  4. All the above

Show answer
Correct Option: A
Explanation:

Apical dominance is a phenomenon in which central stem is dominant and lateral stems are suppressed. It is due to plant hormone auxin produced in the tip of the shoot. Auxin hormone is responsible for apical dominance and cytokinin hormone is responsible for breaking the apical dominance. 

Thus, the correct answer is 'Apical dominance'.

Removal of apical bud makes the plant grow

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Tall

  2. Bushy

  3. Slow

  4. Rapidly

Show answer
Correct Option: B
Explanation:

Apical dominance is a phenomenon in which central stem is dominant and lateral stems are suppressed. It is due to plant hormones produced in the tip of the shoot. Auxin hormone is responsible for apical dominance. When apical bud is removed, lateral buds grow and the plant grows bushy.

Thus, the correct answer is option B.

Apical dominance in plants means

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Growth of lateral buds

  2. Inhibition of growth of lateral buds

  3. Both A and B

  4. None of the above

Show answer
Correct Option: B
Explanation:

Apical dominance is a phenomenon in which central stem is dominant and growth of lateral buds is inhibited. It is due to plant hormones produced in the tip of the shoot. Auxin hormone is responsible for apical dominance and cytokinin hormone is responsible for breaking the apical dominance. 

Thus, the correct answer is option B.

How many shoot aplical meristematic zones are expected in a twig of a plant possessing 9 branches, 39 leaves ?

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. 9

  2. 39

  3. 10

  4. 8

Show answer
Correct Option: C
Explanation:

 Shoot apical meristem is the region in the growing shoot containing meristematic cells. The shoot apical meristem contains multipotent stem cells and produces primordia that develop into all the above-ground organs of a plant.it is always present at the growing apices.

Plants having 9 branches and 39 leaves will have 10 growing apices i.e shoot apical meristematic zones (9 growing apex of the branches +1 growing apex of the main plant axis ).
So, the correct answer is '10'.

In a garden, the gardener cut the apical bud of Lawsonia (mehandi) because 

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. The length should be limited in Lawsonia.

  2. Due to the cutting of apical bud, the effect of Auxins decreases and lateral bud grows and forms dense appearance that is why it can give a definite shape.

  3. Other apical bud grows quickly due to cut of apical bud.

  4. Due to the cutting of apical bud effect of Ethylene decreases and the plant grows rapidly.

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Correct Option: B

In tea plantations and hedge making, gardeners trim the plants regularly so that they remain bushy. Scientific explanation behind this is

apical dominance auxins and gibberellins growth and development plant growth and development biology

  1. Removal of apical dominance

  2. Growth of lateral buds

  3. Suppression of lateral buds

  4. Both (a) and (b)

Show answer
Correct Option: D
Explanation:

Auxin is a hormone present in plants at the tip of the stem. Its function is to maintain apical dominance (where main stem of the plant is dominant over other side branches) and to inhibit growth of lateral buds. That's why gardeners trim the plants regularly so that the plant grows laterally and remains bushy after removal of auxin.

Thus, the correct answer is 'Both (a) and (b).'