PHYTOCHROME CHANGES IN TISSUES OF DARK-GROWN SEEDLINGS REPRESENTING VARIOUS PHOTOPERIODIC CLASSES |
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Authors: | William G Hopkins William S Hillman |
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Institution: | Biology Department, Brookhaven National Laboratory, Upton, N. Y. |
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Abstract: | Excised tissues of dark-grown seedlings representing long day, short day and daylength indifferent photoperiodic classes were assayed for nonphotochemical changes in phytochrome. In all tissues tested, these changes were qualitatively the same. A brief irradiation with red light was followed in darkness by a decrease in total phytochrome, the disappearance of PFR, and an increase in detectable PR. Within the limits of the tissues tested, the kinetics of phytochrome change can be assigned to three groups on the basis of rates. These groups are represented by coleoptiles, hypocotyls and epicotyls, and mesocotyls. The kinetics could not be distinguished on the basis of the photoperiodic class of the mature plant. The significance of these kinetics with respect to the photochemistry of phytochrome conversion is discussed. |
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