a pigment which obsorbs red and far red light is\tcytochrome\tphytochrome\txanthophyll\tcarotene

Phytochromeis aphotoreceptor, apigmentthatplantsuse to detect light. It is sensitive to light in theredandfar-redregion of the visible spectrum. Manyflowering plantsuse it to regulate the time offloweringbased on the length of day and night (photoperiodism) and to setcircadian rhythms.