Plant Growth and Development Question 78

78. What will be the effect on phytochrome in a plant subjected to continuous red light? [1997]

(a) Level of phytochrome decreases

(b) Phytochrome is destroyed

(c) Phytochrome synthesis increases

(d) Destruction and synthesis of phytochrome remain in equilibrium.

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Answer : a

Hints & Solutions

(a) Continuous exposure to red light causes - Conversion of Pr to Pfr which is rapidly destroyed.

  • Inhibition of synthesis of Pr.
  • Total amount of phytochrome decreases.