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Phytochrome is a photoreceptor pigment found in plants that detects light in the red and far-red spectrum. It exists in two forms, Pr and Pfr, which convert between each other when exposed to red or far-red light. Phytochrome plays a regulatory role and is ubiquitous in plants, occurring as a dimer protein with a chromophore pigment molecule. It was discovered in the 1940s-1960s and regulates processes in plants like seed germination, seedling elongation, and flowering.
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- 2. Phytochrome is a photoreceptor, a pigment that plants use to detect light . sensitive to light in the red and far-red region of the visible spectrum. pigment has a regulatory role. ubiquitous
- 3. It exist in two different forms; the Pr form; absorbs at a peak of 660nm. blue form it absorbs red light and converted into Pfr form. Pfr form; absorbs at a peak of 730nm. absorbs far-red light and converted into Pr form.
- 5. Family of proteins with a small covalently bound pigment molecule. Occur as a dimer of two identical polpeptides. Each polypeptide has a prosthetic group called chromophore. The pigment is chromophore (linear tetrapyrole)
- 7. The phytochrome pigment was dicovered by sterling hendricks and harry borthwick in the agriculture research centre in maryland during a period from the late 1940s to the early 1960s.
- 8. They regulate the germination of seed and synthesis of chlorophyll. the elongation of seedling. timing of flowering in adult plants.
- 9. Concern with nuclear gene encoding for mRNAs of chloroplast proteins. Two proteins have been investigated; The small subunit of Rubisco. The light harvesting chlorophyll binding protein (LHCP).
- 11. The corresponding gene for these proteins are rbcS (Rubiso small) and cab (chlorophyll a/b).