Question

In a plant subjected to continuous red light phytochrome will show

• A. Increased synthesis
• B. Decreased level
• C. Destruction
• D. Destruction and synthesis remain in balance

Answer 1

The correct option is A Increased synthesis

If a plant subjected to continuous red light, inactive form of phytochrome P${}_r$ is converted to active form of phytochrome P${}_{fr}$. This is followed by rapid destruction of phytochrome due to prolonged exposure to red light. When the level of phytochrome reaches below critical value, denovo synthesis of P${}_r$ phytochrome takes place. Hence, the destruction and synthesis remain in balance.

Thus, the correct answer is option D.