Which of the following is the site for perception of light/dark in plants?
1. Root apex
2. Shoot apex
3. Leaves
4. Flower

A flash of red light followed by a flash of far-red light given during the middle of the night to a short-day plant will likely 
1. cause increased flower production.
2. have no effect upon flowering.
3. inhibit flowering.
4. stimulate flowering.

Phytochrome is a 
(1) flavoprotein

(2) glycoprotein

(3) lipoprotein

(4) chromoprotein

A few normal seedlings of tomato were kept in a dark room. After a few days they were

found to have become white-coloured like albinos. Which of the following terms will you

use to describe them?

1. Mutated

2. Embolised

3. Etiolated

4. Defoliated

Photoperiodism was first characterised in :-

1. tobacco

2. potato

3. tomato 

4. cotton

Importance of day length in flowering of plants was first shown in 

1. Lemna

2. tobacco

3. cotton

4. Petunia

Phytochromes play a role in 

(1) seed germination

(2) flowering 

(3) photomorphogenesis

(4) photosynthesis.

Which of the following statements is correct regarding short day plants (SDPs)?

1. They can flower in complete darkness if supplied with exogenous nutrients.

2. They are the same as long day plants.

3. They do not have a critical photoperiod.

4. All of these.

Refer the given figures on photoperiodism and select the correct option.

The biological clock measures the length at each night by the?

(1) relative amount of red absorbing and far-red absorbing phytochrome present at dawn

(2) amount of far-red absorbing phytochrome at dusk

(3) relative amount of red absorbing and far-red absorbing phytochrome at mid day

(4) rate at which are kind of phytochrome is converted to the other