Auxin

Q.

The plant hormone used to destroy weeds in a field:

1. IAA

2. NAA

3. IBA

4. 2, 4-D

Q.

What are the physiological effects of cytokinin?

Q.

One of the synthetic auxins is:

1. IBA

2. NAA

3. IAA

4. GA

Q. Apical dominance is caused by

1. Abscisic acid in lateral bud
2. Gibberellin in lateral buds
3. Cytokinin in leaf tip
4. Auxin in shoot tip

Q. Auxin was first isolated from

1. Human urine
2. Callus
3. Coconut milk
4. None

Q.

How does pruning help in making the hedge dense?

Q.

Name two synthetic auxins.

Q.

One hormone hastens the maturity period in juvenile conifers, a second hormone controls xylem differentiation while the third increases the tolerance of plants to various stresses. They are respectively

1. Gibberellin, Auxin and Cytokinin.

2. Gibberellin, Auxin and Ethylene.

3. Gibberellin, Auxin, and ABA

4. Auxin, Gibberellin, and ABA.

Q. Zinc is essential for the biosynthesis of:

1. ABA
2. IAA
3. Cytokinin
4. Ethylene

Q. Which compound is produced by the Calotropis growing in abandoned field as defense mechanism against grazing animals?

1. Nicotine
2. Quinine
3. Cardiac glycosides
4. Caffeine

Q.

Match the following
(a) Indole compounds (i) Kinetin
(b) Terpenes (ii) ABA
(c) Adenine (iii) IAA
(d) Carotenoids (iv) $G{A}_3$

1. a - iii, b - iv, c - i, d - ii

2. a - iv, b - iii, c - ii, d - i

3. a - ii, b - iv, c - i, d - iii

4. a - i, b - ii, c - iii, d - iv

Q.

Name a mineral involved in the synthesis of Auxin.

Q. Differentiation of shoot is controlled by ___________

1. high gibberellin to auxin ratio
2. high gibberellin to cytokinin ratio
3. high cytokinin to auxin ratio
   
4. high auxin to cytokinin ratio

Q.

Name a hormone which

A. is gaseous in nature

B. is responsible for phototropism

C. induces femaleness in flowers of cucumber

D. is used for killing weeds (dicots)

E. induces flowering in long day plants.

Q.

Is auxin toxic to humans?

Q. Match the following:
$\begin{array}{cc}\text{Plant Growth Regulators}& \text{Functions}\\ \text{1.Auxin}& \text{A.Promotes seed germination}\\ \text{2.Gibberellin}& \text{B.Helps to overcome apical dominance}\\ \text{3.Cytokinin}& \text{C. Promotes apical dominance}\end{array}$

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

Q. IAA and IBA are auxins while NAA and 2, 4-D are auxins.

1. natural
2. semi-synthetic
3. synthetic
4. semi-natural

Q.

Question 30.01:

Auxins are growth hormones capable of promoting cell elongation. They have been used in horticulture to promote growth, flowering and rooting. Write a line to explain the meaning of the following terms related to auxins.
Auxins precursors

Anti-auxins

Synthetic auxins

Q.

Which of the following plant growth regulators (PGRs) promote root initiation, flowering, and induced parthenocarpy?

1. Gibberellin

2. Cytokinin

3. Auxin

4. Ethylene

Q. IAA and IBA are auxins while NAA and 2, 4-D are auxins.

1. natural
2. semi-synthetic
3. synthetic
4. semi-natural

Q. This question consists of two statements, Assertion and Reason. While answering this question you are required to choose any one of the following five responses.

Assertion: A correct concentration of auxin and cytokinin is required for the development of root and shoot in a callus.

Reason: When the ratio of kinetin to auxin is high, then only shoots develop. But when the ratio is low then only roots develop.

Q. During somatic hybridisation

1. somaclones are produced in large numbers
2. the apical meristems are cultured to get virus-free plants
3. the cell walls and the middle lamella are digested before fusing the cells
4. crop plants with higher levels of vitamins, proteins and minerals are hybridised

Q. Who showed that shoots can be induced in the callus by balanced supply of cytokinin and auxin in the medium?

1. White
2. Haberlandt
3. Yabuta
4. Skoog and Miller

Q.

Give the five types of hormones in plants.

Q. Describe an experiment that would demonstrate that growth stimulating hormone is produced at the tip of coleoptile.

Q. Assertion :Decapitation is widely used in tea plantation and hedge-making. Reason: Removal of shoot tips usually results in the growth of lateral buds.

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. Both Assertion and Reason are incorrect

Q.

Question 13:

Fill in the places with appropriate word/words.
A phase of growth which is maximum and fastest is _________

Apical dominance as expressed in dicotyledonous plants is due to the presence of more _________ in the apical bud than in the lateral ones.

In addition to auxin, a _________ must be supplied to culture medium to obtain a good callus in plant tissue culture.

_________ of a vegetative plants are the sites of photoperiodic perception.

Q. Choose the correct answer from the alternatives given.
How does auxin actually work?

1. In the presence of blue light, it triggers additional photosynthesis and growth
2. In the presence of light, it increases the turgor pressure of the cell and accelerates growth
3. In the presence of light, it increases the formation of hydrolytic enzymes that release energy needed for growth purposes
4. In the presence of unidirectional light, it moves to the shady side and activates an ATP-driven proton pump that results in weakened cell wall and eventual elongation

Q. The synthetic hormone used as a weedicide is

1. malic hydrazide
2. indole 3-acetic acid
3. gibberellic acid
4. 2, 4-dichlorophenoxyacetic acid

Q. Very short answer type.
Where are auxins synthesised in plants? Mention any two functions of auxins.