Biology Multiple Choice Questions on “Plant Growth and Development – Photoperiodism and Vernalisation”.
1. Which of the crops doesn’t show vernalisation?
a) Wheat
b) Barley
c) Rice
d) Rye
Answer: c
Clarification: Rice doesn’t show vernalisation. Other crops such as Wheat, Barley and rye which are have two varieties: spring and winter require cold treatment to stimulate photoperiodic response of plants.
2. Plants are able to measure the duration of exposure to light.
a) True
b) False
Answer: a
Clarification: Flowering in plants depends upon the period of exposure of light to the plant. Plants are able to measure the duration of sunlight received through leaves. A hypothetical hormone Florigen is said to be responsible for flowering.
3. Statement A: Critical duration is different for different plants.
Statement B: The plants which are dependent on critical duration are called day-neutral plants.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: c
Clarification: Critical duration is a well-defined period of exposure of plant to light and dark conditions for initiation of flowering in plants. It is different for different plants. Some require exposure less than critical duration such as short day plants. Some plants require exposure more than the critical duration such as long day plants. Also there are plants which are independent of the critical duration. They are called as day-neutral plants.
4. Which of the following plants is a polycarpic plant?
a) Sugarbeet
b) Cabbage
c) Carrots
d) Apple
Answer: d
Clarification: Polycarpic plants are plants that set seeds numerous times before senescence. Apple is a polycarpic plant. Sugarbeet, Cabbage & Carrots are some of the common biennials. Biennials are plants that take 2 seasons to complete their lifecycle.
5. Statement A: Short day plants required more exposure to light than the critical duration.
Statement B: Long day plants required less exposure to light than the critical duration.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: b
Clarification: A well-defined exposure to light and dark conditions are pre-requisite for initiation of flowering in plants. Short day plants required less exposure to light than the critical duration. Long day plants required greater exposure to light than the critical duration.
6. Statement A: Vernalisation prevents precocious reproductive development.
Statement B: Vernalisation promotes flowering by cold treatment.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: a
Clarification: Vernalisation is the process which improves qualitative and quantitative flowering in plants by exposure to cold conditions. It has dual functions. It allows the plants to attain full maturity. It also stimulates early flowering of plants by providing the desired conditions.
7. Duration of light period is more important than the duration of dark period.
a) True
b) False
Answer: b
Clarification: Both the durations of light and dark are equally important. The critical duration of the periods is essential for the proper functioning of phytochromes present in the plant.
8. Statement A: Response of plants to low temperature is regulated by a hypothetical hormone.
Statement B: Response of plants to different periods of light is also regulated by a hypothetical hormone.
a) Both the statements are true
b) Both the statements are false
c) Statement A is true but Statement B is false
d) Statement B is true but Statement A is false
Answer: a
Clarification: Vernalisation is the process which improves qualitative and quantitative flowering in plants by exposure to cold conditions. Response of plants to low temperature is regulated by a hypothetical hormone, Vernalin. Photoperiodism is the response of plants to duration of exposure to light and dark conditions. It is also regulated by a hypothetical hormone, Florigen.
9. Which is the site for perception of light/dark duration?
a) Leaves
b) Stem
c) Roots
d) Apical bud
Answer: a
Clarification: Leaves are the site for perception of light/dark duration. Florigen is responsible for flowering. Shoot apices are modified to flowering apices prior to flowering. The hormone further migrates to stem and roots.
10. The hormone responsible for flowering is ________
a) vernalin
b) cytokinin
c) ABA
d) florigen
Answer: d
Clarification: The hypothetical hormone florigen is said to be responsible for flowering in plants. Vernalin is promotes early maturity leading to flowering. ABA is majorly an inhibitor and functions in stressful conditions. Cytokinin stimulates shoots development.