Question

The day-neutral plant is
(a) Tobacco
(b) Tomato
(c) Wheat
(d) Oat

Answer 1

Hint: Day-neutral plants are those plants, which flower after a period of vegetative growth regardless of the duration of light falling on that plant. Genes are said to be responsible for controlling the photoperiodic response.

Complete answer:
Tomato is a day-neutral plant. Some other examples of day-neutral plants are cucumber, cotton, dandelion, sunflower, and some varieties of pea. The day-neutral plants are also known as photo neutral plants or indeterminate plants.

Additional Information:
1. Characteristics of short-day plant:
- Short day plants require a long period of darkness and a short period of light to flower. These flowers in the spring season e.g., rice, tobacco, cotton.
- A short day plant would flower when the dark period in its daily cycle exceeds 9 hours.
- In a short-day plant, a period of darkness during the day time does not affect flowering.
2. Characteristics of the long-day plant:
- Long day plants flower when they are exposed to a short period of darkness and a long period of light. These flowers in the summer season e.g., lettuce, spinach, potato.
- In long-day plants, periods of darkness have inhibitory effects on flowering.
- In long-day plants, a photoperiod of 15 hours per day is needed for flowering.
- It has been observed that the photoperiodic stimulus is perceived in the leaves of the plant.
- Scientists have proposed the existence of a flowering hormone called florigen.

So the correct answer is, ‘Tomato.’

Note: The response of plants to relative lengths and alternations of light and dark periods concerning the initiation of flowering is called photoperiodism. Flowering is just like seed germination, is a phytochrome (photoreceptors in plants) mediated process.