phytochrome(redirected from Phytochrome a)
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Any of several photoreceptive pigments in green plants that regulate processes such as flowering and seed germination.
(Botany) botany a blue-green pigment existing in two interchangeable forms, present in most plants, that mediates many light-dependent processes, including photoperiodism and the greening of leaves
a plant pigment that is associated with the absorption of light in the photoperiodic response and that may regulate various types of growth and development.