210 likes | 579 Views
Corn and mustard seedlings grown either in the light or the dark. Lettuce seed germination is a typical photoreversible response . Absorption spectra of purified phytochrome in the Pr and Pfr forms overlap.
E N D
Corn and mustard seedlings grown either in the light or the dark
Lettuce seed germination is a typical photoreversible response
Absorption spectra of purified phytochrome in the Pr and Pfr forms overlap
Three types of phytochrome responses, based on their sensitivities to fluence
LFR action spectra for photoreversible stimulation / inhibition of seed germination
Figure 17.7 Several structural domains in phytochrome and cellular changes it mediates
Figure 17.10 Nuclear localization of phy–GFP in epidermal cells of Arabidopsis hypocotyls
Figure 17.11 Phytochrome deficiencies alter growth and development in pea and tomato
Figure 17.12 Differences in phytochrome gene family structure and function
Phytochrome activation affects membrane potential (~5 sec) • Phytochrome affects transcription (lag time of less than 5 min)
Transcriptional regulation • Phytochrome interacting factors (PIFs) act as negative regulators of phytochrome response: PIF mutants exhibit a constituativephotomorphogenic response even when plants are grown in the dark. • Phytochrome initiates degradation of PIFs in the nucleus
Figure 25.23 Phytochrome control of flowering by red (R) and far-red (FR) light