MCQs on Auxin

Auxins are a group of plant hormones present in a very small quantity but play an important role in the growth and differentiation of various parts of plants. IAA and IBA are naturally occurring auxins. They promote cell elongation, fruit development, root initiation from cuttings and are responsible for apical dominance and phototropism.

1. Application of ________ can delay abscission of fruits and leaves at early stages

(a) gibberellic acid

(b) ethylene

(c) auxin

(d) cytokinin

2. Flowering can be induced in pineapple by application of

(a) Abscisic acid

(b) NAA, 2,4­-D

(c) Phenylacetic acid

(d) Cytokinin

3. Find the incorrect match

(a) Abscisic acid ­- Stomatal closure

(b) IAA ­- Cell wall elongation

(c) Cytokinin ­- Cell division

(d) Gibberellic acid ­- Leaf abscission

4. Uneven distribution of _______ results in phototropic curvature

(a) phytochrome

(b) auxin

(c) gibberellin

(d) cytokinin

5. The Avena curvature test is an accurate bioassay for

(a) ABA

(b) GA3

(c) IAA

(d) Ethylene

6. Which one of these is commonly used synthetic auxin?

(a) NAA

(b) IAA

(c) IBA

(d) GA

7. Auxin is transported polarly. Mostly, auxin movement is

(a) acropetal

(b) basipetal

(c) centripetal

(d) both (a) and (c)

8. Removal of apical bud results in

(a) more axillary buds

(b) flowering ceases

(c) more lateral branches

(d) plant growth ceases

9. Commonly applied hormone in tea plantation is

(a) abscisic acid

(b) ethylene

(c) indole-­3-­acetic acid

(d) zeatin

10. Which of the following combination of hormones will promote differentiation of shoot as well as root in tissue culture?

(a) Gibberellin and abscisic acid

(b) Auxin and abscisic acid

(c) IAA and gibberellin

(d) Auxin and cytokinin


1. (c) 2. (b) 3. (d) 4. (b) 5. (c)
6. (a) 7. (b) 8. (c) 9. (c) 10. (d)

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