Apical Dominance

Q.

What is the chemical name of auxin?

Q. Apical dominance means ______.

1. stimulation of a growth of apical buds by the removal of axillary buds
2. suppression of growth of apical buds by the axillary buds
3. inhibition of growth of axillary buds by the removal of axillary buds
4. suppression of growth of axillary buds by the presence of apical buds

Q. Mention any one physiological effect of $ABA$ on plants.

Q.

Question 21:

In botanical gardens and tea gardens, gardeners trim the plants regularly so that they remain bushy. Does this practice have any scientific explanation?

Q. The growing apical buds inhibit the lateral buds. This phenomenon is

1. senescence

2. Parthenocarpy

3. Apical dominance

4. Abscission

Q. In tissue culture, which of the following combinantions of growth hormones need to be added to induce shoot growth?

1. Only auxin or only cytokinin
2. Higher concentration of auxin and lower concentration of cytokinin
3. Higher concentration of cytokinin and lower concentration of auxin
4. Both auxin and cytokinin in equal amounts

Q.

What will happen if terminal buds are removed form the plant?

1. Plant dies

2. The lateral buds grow profusely

3. The roots die

4. The shoot dies

Q.

To get carpet-like grass lawns are mowed regularly. Is there any scientific explanation for this?

Q. Pruning of tea plants is done to discard the effects of:

1. Auxin
2. $G{A}_3$
3. Cytokinin
4. ABA

Q.

What is the mechanism underlying the phenomenon by which the terminal/ apical bud suppresses the growth of lateral buds? Suggest measures to overcome this phenomenon.

Q.

How does pruning help in making the hedge dense?

1. It induces the differentiation of new shoots from the rootstock

2. It frees axillary buds from apical dominance

3. The apical shoot grows faster after pruning

4. It released wound hormones

Q.

Label the diagram

A. This is which part of dicotyledonous plants?

B. If we remove part 1 from the plant, what will happen?

Q. Hormones that promotes growth of lateral buds/has negative effect on apical dominance is

Q. Which of the following effects of auxins on plants are the basis for commercial application?

1. Callus formation
2. Curvature of stem
3. Induction of root formation in stem cuttings
4. All of the above

Q. Compare the statement A with B. Statement A: Auxins produce apical dominance by suppressing the activity of lateral buds. Statement B: In horticulture, periodic pruning of shoot tips is done to make mulberry plants bushy.

1. Both the statements A and B are correct and A is the reason for B.
2. Statement A is correct and B is wrong.
3. Both the statements A and B are correct and A is not the reason for B.
4. Statement B is correct and A is wrong.

Q. Apical dominance means

1. Suppression of growth of apical bud by axillary buds
2. Suppression of growth of axillary buds by the presence of apical buds
3. Stimulation of growth of axillary buds by removal of apical buds
4. Inhibition of growth of axillary buds by removal of apical buds

Q. The hormone responsible for apical dominance is

1. IAA
2. GA
3. ABA
4. Florigen

Q. Which of the following statements are true with respect to the plant growth regulators used in a growth medium for tissue culture?

I - The specific concentration of the plant growth regulators (PGRs) in the culture medium does not influence the fate of the explant.
II - PGRs play an important role in inducing de-differentiation of the cells of the explant.
III - When parenchyma cells of a callus are cultured in a medium containing high levels of cytokinin, shoot formation is induced.

1. I and III
2. I and II
3. Only I
4. II and III

Q. A leaf after being plucked from a plant can still remain green if it is dipped in:

1. Auxin
2. Gibberellin
3. Cytokinin
4. Abscisic acid

Q. Assertion :Ethylene induces ripening. Reason: Ethylene is a gaseous hormone

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q. Which growth hormone is responsible for apical dominance?

1. Auxin
2. Cytokinin
3. Gibberellin
4. Ethylene

Q.

Auxins promote the following.

1. Shedding of fruits

2. Bud dormancy

3. Leaf fall

4. Apical dominance

Q. The phenomenon wherein, the ovary develops into a fruit without fertilisation is called.

1. Parthenocarpy
2. Apomixis
3. Asexual reproduction
4. Sexual reproduction

Q. Which one is the main effect of auxin, important for commercial purpose?

1. Parthenocarpy
2. None of these
3. Early rooting in stem cutting
4. Weed Killer

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

1. Removal of apical dominance
2. Growth of lateral buds
3. Suppression of lateral buds
4. Both (a) and (b)

Q. Apical dominance as found in higher plants is due to

1. Photoperiodism
2. Enzymes
3. Phototropism
4. Hormones

Q. Ethylene promotes senescence and is found in high concentration in ripened fruits.

1. True
2. False

Q. State whether the following statements are true or false.
Plant growth is stimulated by the presence of auxins, ethylene, and abscisic acid.

1. True
2. False

Q. Haploid plant cultures can be obtained from

1. Leaves.
2. Root tip.
3. Pollen grain.
4. Buds.

Q. The hormones responsible for apical dominance is

1. IAA
2. Florigen
3. GA
4. ABA