Question

If a tree flowers thrice in a year in 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. Thermosensitive but photo-insensitive

Answer 1

Hint: The ability of a plant to respond to changes in light and temperature is known as photosensitivity and thermosensitivity respectively. The process of flowering in plants is dependent on these two abilities of a plant along with vernalization.

Complete answer: Plants can detect and can even respond to the light, gravity, Changes in the temperature, chemicals and habitat.
They respond to the changing seasons of weather and initiate their developing and flowering process.
The photoperiodic is the main factor for the flowering and light quality while the thermosensitivity and GA pathways are responsible for regulating its flowering time.
So basically both vernalization and the photoperiodic are much responsible for the flowering and growth of the tree.
Hence we could say the tree that flowers which flower thrice a year should be both photo and thermosensitive.

Hence, the correct option is (A), Photo-and thermo-sensitive.

Note: The ability of a plant to show phototropism, thermotropism, or both is dependent upon its interaction with the environment and the need of the plant under various climatic conditions.