Question

The short day plant is
a. Tomato
b. Sunflower
c. Cotton
d. Potato

Answer 1

Hint: Short-day plants are those, where the flowering of plants takes place when the day is usually shorter than the critical day length, where they require a long period of darkness and a short period of daylight for them to flower.

Complete answer:
Photoperiodism is the physiological reaction of organisms such as plants or animals to the darkness or length of the night. Some plants should be exposed to a particular period of the light in order to flower, this phenomena is mainly discovered by Charles Darwin and his son.
Most of the plants which flower, usually utilize the Photoperiodism in order to flower, this process of Photoperiodism is mainly due to the presence of some photo proteins such as photochrome or cytochrome where they act as photoreceptors

They are divided into 3 types
- Short day plants
- Long day plants
- Day-neutral plants.

> Short day plants: The plants which require less exposure of light to flower is said to be short-day plants
Research and investigation states that short-day plants require more darkness for the plants to flower
Some of the examples of the short-day plants include Rice, cotton, soybeans, green gram, jowar, hibiscus, etc,

> Long day plants: These plants require more exposure of light to flower, which is said to be long day plants
Most of the long day plants usually flower in late springs and early summer
Some of the examples of long-day plants include peas, oats, Barley, lettuce, wheat, radish, sugar beats, potatoes, etc

> Day-neutral plants: This plants usually flower, as they grow old but does not depend on day length and all
Some of the examples of the Day-neutral plants include cucumber, corn, tomato, sunflower, etc

So when we look at option wise, the first one is Tomato, where it is an example of a day-neutral plant and the length of the day and night does not affect this plant in flowering.
Another option is a sunflower, this also comes under the day-neutral plant and another one is potato it is a long-day plant, and the next one is cotton, it is an example of a short-day plant

Note: Within the group of short day and long day plants, further there are two small groups which are qualitative and quantitative plants, where euphorbia is an example of qualitative plants and rye is an example of quantitative plants.