Phytochrome prevents seeds of some plants from germinating when they are in deep shade by the:

Question

Quizplus · Accepted Answer

Phytochrome is a photoreceptor protein that is sensitive to red and far-red light. When a seed is in deep shade, it receives very little red light and an abundance of far-red light. Phytochrome in its inactive form (Pr) absorbs red light, causing it to convert into its active form (Pfr), which signals for germination to begin. However, when phytochrome absorbs far-red light, it converts back into its inactive form. Therefore, in deep shade, phytochrome absorbs more far-red light than red light, leading to the inhibition of germination. Choice C specifically refers to the absorption of far-red wavelengths by the Pfr form of phytochrome.

Phytochrome Prevents Seeds of Some Plants from Germinating When They