A)Light-grown corn(B)Dark-growncorn(c)Light-grownbeanD)Dark-grown beanFigure 9-1
Figure 9-1
545福Red Far-redRedDarkFigure 9-2FIGURE17.2Lettuce seedgerminationisatypical photoreversible response controlledbyphytochrome.Red lightpromotes lettuce seed germination, but this effect isreversed byfar-red light.Imbibed (water-moistened)seedsweregiven alternatingtreatments ofred followed byfar-red light.The effect of the light treatment depended on thelasttreatmentgiven.(PhotosM.B.Wilkins.)Red Far-redRed Far-redRedFar-redRed
Figure 9-2
First node1212Epicotyl220Cotyledon10FIGURE17.6 Phytochrome is20most heavilyconcentrated inRootthe regions where dramaticdevelopmental changes areoccurring:theapical meristems20oftheepicotylandroot.Shownhere is the distribution of phy10tochrome in an etiolated peaseedling,asmeasured spectrophotometrically.(FromKendrickandFrankland1983.ConcentrationofphytochromeFigure 9-3
Figure 9-3
Chromophore:phytochromobilinRPrRHisapidadioB-aNC10H1HTisPrPUCis isomerThioetherlinkageGlrRed lightconvertscisto transRProR15CHisHBN-H510TransisomerHHisPfrLeuFigure 9-5Structureof thePrand Pfrformsofthechro-FIGURE17.4mophore(phytochromobilin)and thepeptideregionboundto the chromophore through a thioether linkage.The chro-mophore undergoes a cis-trans isomerization atcarbon 15inresponse to red and far-red light.(AfterAndel etal.i997.)
Figure 9-5
Chromophore-bindingdomainsIAIIAIBIIBFIGURE17.5Structureofthephytochromedimer.Themonomers arelabeled I and I.Eachmonomer consists of achromophore-binding domain(A)and asmallernonchro-mophore domain (B).The moleculeas a wholehas anellipsoidal rather than globular shape.(After Tokutomi et al.1989.)Figure 9-5-1
Figure 9-5-1