Photoperiodism

Q. Photoperiodism was first characterized in

1. Tobacco
2. Potato
3. Tomato
4. Cotton

Q.

Which pigment is involved in photoperiodic change in plants?

1. Phytochrome

2. Cytochrome

3. Chlorophyll

4. Anthocyanin

Q. What is the site of perception of photoperiod necessary for induction of flowering in plants?

1. Leaves
2. Lateral buds
3. Pulvinus
4. Shoot apex

Q.

The pigment melanin which imparts coloration to the skin is found in the malpighian layer.

1. True
2. False

Q.

The portion of a plant that is grafted on to the other plant is called ___________ and the plant in which grafting is performed is called the ______________.

Q. Assertion: Shoot apices tend to modify themselves into flowering apices before flowering. Reason: Shoot apices can’t perceive photoperiods.

1. Both assertion and reason are correct and the reason is the correct explanation to the assertion
2. Both assertion and reason are correct but the reason is an incorrect explanation to the assertion
3. Only assertion is correct
4. Both are incorrect statements

Q.

The phenomenon of photoperiodism explains ____.

1. The effect of day length on plant growth

2. The recurrence of day and night

3. The effect of day length on flowering

4. The movement of plant organs in response to day light

Q.

Photoperiodism was first characterized in:

1. Potato

2. Tobacco

3. Tomato

4. Cotton

Q. Assertion: Chrysanthemum is flashed with 660 nm of light, the flower does not bloom even if the light period is well below the critical photoperiod. Reason: Chrysanthemum is a long-day flowering plant.

1. Both assertion and reason are correct statements and reason is the correct explanation to the assertion
2. Both assertion and reason are correct statements and reason is an incorrect explanation to the assertion
3. Only assertion is correct
4. Both assertion and reason are incorrect

Q. Assertion : Dark period is equally important for flowering like the light period
Reason : Flowering occurs in short day plants if the dark period is interrupted by light period

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

Q. Assertion: A defoliated plant can respond to photoperiodic stimulation.

Reason: It is the shoot apices that perceive light to induce flowering.

Select the appropriate option:

1. Both assertion and reason are correct statements and the reason is the correct explanation of the assertion
2. Both assertion and reason are correct statements but the reason is an incorrect explanation of the assertion
3. Only assertion is correct
4. Both assertion and reason are incorrect

Q. The response of plants to the changing duration of light and dark periods is termed as .

1. phototropism
2. photoperiodism
3. heliotropism
4. dormancy

Q. Certain pigments regulate the process of photoperiodism. The pigments exist in two photochemically inter-convertible forms, operating at two different wavelength of light.
The pigments in question are the:

1. Carotenoids
2. Xanthophylls
3. Phytochromes
4. Chlorophylls