Role of Auxin

Q.

How is auxin used in agriculture?

Q. Xylem differentiation is facilitated by

1. auxin
2. cytokinin
3. gibberellin
4. ethylene

Q.

The phototropic curvature is the result of uneven distribution of:

1. Gibberellin

2. Phytochrome

3. Cytokinins

4. Auxin

Q. Positive geotropic movement of root in a horizontally placed seedling is due to

1. New cells that arise on the lower side of root
2. Condensation of cells decrease on the lower side of root
3. Auxins accumulate on the upperside of root, so cell elongation decreases in that area
4. Auxins accumulate on the lower side of root, so cell elongation decreases towards lower side

Q. Identify the incorrect statement related to the physiological roles of auxins

1. Auxins help to promote fruit and leaf drop at early stages but prevents the abscission of older mature leaves and fruits
2. Auxins promote flowering in pineapples
3. Auxins induce parthenocarpy
4. High auxin concentration promote more female flower formation

Q.

Give important functions of auxins.

Q. The bioassay for auxin is

1. Avena coleoptile curvature test
2. Canary grass curvature test
3. Avena elongation test
4. α-amylase synthesis test

Q. The bioassay for auxin is

1. Avena coleoptile curvature test
2. Canary grass curvature test
3. Avena elongation test
4. α-amylase synthesis test

Q. Synthetic hormone used as a weedicide is

1. 2, 4-D
2. IBA
3. NAA
4. PAA

Q. The diffusible substance synthesised in the coleoptile tip causes phototropic bending. This was confirmed by

1. Boysen-Jensen
2. F.W Went
3. Paal
4. Charles Darwin and Francis Darwin

Q.

The phototropic curvature is the result of uneven distribution of:

1. Gibberellin

2. Phytochrome

3. Cytokinins

4. Auxin

Q. Scientists use various combinations of auxin and cytokinin in plant tissue culture experiments. Choose the correct statement from the options given below regarding the role of both hormone in plant culture medium.

1. High cytokinin-auxin ratio promotes shoot formation
2. High cytokinin-auxin ratio promotes root formation
3. Low cytokinin-auxin ratio promotes root formation
4. Low cytokinin auxin ratio promotes shoot formation

Q. The pre-harvest fruit drop is due to the

1. decrease in the level of ABA
2. decrease in the level of auxin
3. increase in the level of auxin
4. decrease in the level of gibberellin

Q. Choose the important physiological effects of auxin:

1. Cell
   enlargement
2. Fruit
   ripening
3. Rooting
4. Tropism
5. Shedding
   leaves
6. Apical
   dominance
7. Parthenocarpy
8. Cell
   enlargement

Q. Positive geotropic movement of root in a horizontally placed seedling is due to

1. New cells that arise on the lower side of root
2. Condensation of cells decrease on the lower side of root
3. Auxins accumulate on the upperside of root, so cell elongation decreases in that area
4. Auxins accumulate on the lower side of root, so cell elongation decreases towards lower side

Q.

The property of auxins that is of great horticultural importance is ______.

1. Cell elongation
2. Parthenocarpy
3. Apical dominance
4. Root initiation

Q. Scientists use various combinations of auxin and cytokinin in plant tissue culture experiments. Choose the correct statement from the options given below regarding the role of both hormone in plant culture medium.

1. High cytokinin-auxin ratio promotes shoot formation
2. High cytokinin-auxin ratio promotes root formation
3. Low cytokinin-auxin ratio promotes root formation
4. Low cytokinin auxin ratio promotes shoot formation

Q.

Match the following columns:

Column 1	Column 2
Auxin	Apical dominance
Cytokinin	Shoot development
Gibberellin	Dormin
Abscisic acid	Parthenocarpy