Question

If a tree flowers thrice in a year, in the months of October, January and July in northern India the plant is

• A. Photo and thermo-sensitive.
• B. Photo and thermo-insensitive.
• C. Photosensitive but thermo-insensitive.
• D. Thermo-sensitive but photo-insensitive.

Answer 1

The correct option is B Photo and thermo-insensitive.

Plants are able to detect and respond to light, gravity, changes in temperature and chemicals. Plants respond to the changing seasons to initiate their development and flowering. The photoperiodic stimulus is found to be responsible for flowering, light quality, vernalization, autonomous and GA pathways are also responsible for regulating the flowering time in plants. While vernalization and photoperiodic pathways are environmental dependents, the autonomous pathway promotes flowering in all conditions. Hence for a tree that flowers thrice a year, the plant has to be both photo and thermo-insensitive.