Plant Growth Regulators

Q.

List five main groups of natural plant growth regulators. Write a note on the discovery, physiological functions and agricultural/horticultural applications of any one of them.

Q. Which of the following is an adenine derivative?

1. Indole-3-acetic acid
2. Abscisic acid
3. Ethylene
4. $N^6$-furfurylamino purine

Q. Match column I to column II Column I Column II

A. Indole compounds	1. $Kinetin$
B. Adenine derivatives	2. $C_2{H}_4$
C. Derivatives of carotenoids	3. $IAA$
D. Terpenes	4. $G{A}_3$
E. Gases	5. $ABA$

1. A-1, B-4, C-5, D-3, E-2
2. A-3, B-1, C-5, D-4, E-2
3. A-1, B-3, C-5, D-4, E-2
4. A-3, B-1, C-4, D-5, E-2

Q.

Name various plant hormones. Also, give their physiological effects on plant growth and development.

Q.

The name of a gaseous plant hormone is

1. IAA

2. Gibberellin

3. Ethylene

4. Abscisic acid

Q. The bottled fruit juices bought from the market are clearer as compared to those made at home. This is because

1. bottled juices are clarified by the use of streptokinase
2. bottled juices consist of lowering agents
3. bottled juices are clarified by the use of pectinases and proteases
4. none of these

Q. ________ hormone is considered as a plant growth promoter as well as a plant growth inhibitor.

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

Q.

Define plant growth promoters.

Q.

The substance that triggers the fall of mature leaves and fruits from plants is due to

1. auxin

2. gibberellin

3. abscisic acid

4. cytokinin

Q.

Pick out the correct statements.
I. Cytokinins especially help in delaying senescence.
II. Auxins are involved in regulating apical dominance.
III. Ethylene is especially useful in enhancing seed germination.
IV. Gibberellins are responsible for immature falling of leaves.

1. I and III

2. I and II

3. II and IV

4. I and IV

Q. Match the columns and select the correct option.

	Hormones		Functions
A.	Cytokinin	I.	Senescence
B.	Ethylene	II.	Abscission
C.	Abscisic acid	III.	Cell growth
D.	Auxin	IV.	Shoot and root formation

1. A-III, B-I, C-II, D-IV
2. A-I, B-II, C-III, D-IV
3. A-II, B-I, C-III, D-IV
4. A-II, B-IV, C-I, D-III

Q. Which of the following is an adenine derivative?

1. Indole-3-acetic acid
2. $N^6$-furfurylamino purine
3. Abscisic acid
4. Ethylene

Q.

Deciduous plants shed their leaves during hot summer or in autumn. This process of shedding of leaves is called abscission. Apart from physiological changes what anatomical mechanism is involved in the abscission of leaves.

Q.

What effect could plant hormones have on humans?

Q. Most intensively studied gibberellin is -------------
__

Q. Which one of the following is an agent orange?

1. Weedicide with dioxin
2. Chemical used in luminous paint
3. Biodegradable insecticide
4. Colour used in fluorescent lamp

Q. The PGR, ethylene, could fit either the groups- plant growth promoters and inhibitors but it is largely an

1. Supporter of growth activities
2. Inducer of growth activities
3. Promoter of growth activities
4. Inhibitor of growth activities

Q. Which of the following is not a plant growth regulator?

1. Indole acetic acid
2. Terpenes
3. Carotenoid derivatives
4. Zinc

Q. Fungal hyphae with two genetically distinct nuclei are said to be

1. polykaryotic
2. monokaryotic
3. dikaryotic
4. heterokaryotic

Q.

How do the leaves of poinsettia plants turn red?

Q. During metabolic activation of oocyte,

1. large number of inactivated DNA strands in the cytoplasm gets activated.
2. large number of inactivated mRNA strands in the cytoplasm gets activated.
3. large number of inactivated mRNA strands in the nucleus gets activated.
4. large number of inactivated DNA strands in the nucleus gets activated.

Q.

Which plant hormone is responsible for phototropism?

Q. Which of the following plant growth regulators is gaseous in nature?

1. Ethylene
2. Abscisic acid
3. Indole acetic acid
4. Cytokinin

Q.

The name of a plant growth regulator extracted from a fungus by Yabuta and Hayashi is

1. Auxin

2. Gibberellin

3. Kinetin

4. Abscisic acid

Q.

Dikaryon formation occurs in

1. Phycomycetes and slime moulds

2. Ascomycetes and Basidiomycetes

3. Phycomycetes and Basidiomycetes

4. Ascomycetes and slime moulds

Q. Assertion: Phytohormones are the plant compounds that can promote and inhibit the plant growth.
Reason: There are some phytohormones like auxin, cytokinins which play a role in plant growth and some phytohormones like abscisic acid which inhibit the plant growth.

1. Both assertion and reason are true and the reason is the correct explanation of the assertion
2. The assertion is true but the reason is false
3. Both assertion and reason are true but the reason is not the correct explanation of the assertion
4. Both assertion and reason are false

Q. which one of the following hormone is involved in phototropism?

1. 2, 4-D
2. IAA
3. Kinetin
4. GA3

Q.

The term cytokinin was coined by

1. Letham

2. E. Kurosowa

3. Miller

4. Denny

Q.

Name the following:
A hormone essential for cell division in plants.

Q.

What types of toxins can be released by harmful algal blooms?