Q. No.Plants bend toward light because
1.
light is the source of energy that drives photosynthesis.
2.
the sun stimulates stem growth.
3.
cell expansion is greater on the dark side of the stem.
4.
there is inactivation of auxin on the dark side of the stem.
The production of which of the following plant hormones by the apical bud of a pine tree inhibits the growth of lateral buds?
1. ABA.
2. cytokinin.
3. gibberellin.
4. auxin.
A plant has been forcibly put into a horizontal position. After some time, the tip of this plant grows:
1. upwards.
2. downwards.
3. straight horizontally.
4. unpredictably.
A piece of parenchyma tissue from a plant is cultured in the absence of cytokinins. The expected result is that:
| 1. | the cells grow smaller with each division. |
| 2. | the cells grow very large but do not divide. |
| 3. | the cells grow very smalland do not divide. |
| 4. | the cells grow large and divide more rapidly than normal. |
In a tissue culture experiment, the undifferentiated callus will develop shoot buds if:
| 1. | amount of auxin and cytokinin is equal in the medium |
| 2. | amount of auxin is more than the amount of cytokinin in the medium |
| 3. | amount of cytokinin is more than the amount of auxin in the medium |
| 4. | the medium lacks auxin and cytokinin but has other plant growth regulators |
Plant growth regulators do not:
| 1. | act by altering gene expression. |
| 2. | have multiple effects. |
| 3. | function independently of other hormones. |
| 4. | control cell division and cell differentiation |
The control of apical dominance is due to interaction of auxins, cytokinins and a newly discovered plant hormone called as:
1. Brassinosteroids
2. Jasmonates
3. Salicylic acid
4. Strigolactones
To promote stem elongation, gibberellins act in concert with:
| 1. | Auxins | 2. | Cytokinins |
| 3. | Ethylene | 4. | ABA |
Identify the incorrect statement regarding gibberellins:
| 1. | All are acidic |
| 2. | Cause bolting in plants with rosette habit |
| 3. | Delay the maturity period of juvenile conifers |
| 4. | Speed up malting process in brewing industry |
The removal or inactivation of which of the following will lead to germination of many types of dormant seeds?
| 1. | ABA | 2. | Ethylene |
| 3. | Cytokinins | 4. | Gibberellins |
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