Light The Source of all Biological Energy Trapped in Photosynthesis Used to determine Seasons
Light: An Energy Waveform With Particle Properties Too wavelength violet 400 blue green yellow orange red 500 600 wavelength (nm) 700 nm 10 -9 meter 0. 00001 meter!
Light: An Energy Waveform With Particle Properties Too wavelength visible spectrum 400 500 600 wavelength (nm) 700 nm 10 -9 meter 0. 00001 meter!
White light: all the colors humans can see at once http: //www. alanbauer. com/photogallery/Water/Rainbow%20 over%20 Case%20 Inlet-Horz. jpg
http: //www. chez. com/uvinnovation/ site/images/introduction/apple_logo. gif Which side of our brains are we using? http: //jojoretrotoybox. homestead. com/files/Rainbow_Brite_Logo_2. jpg http: //www. astrostreasurechest. ne t/websmurfclub/images/pinsmurf oncloudrainbow. jpg http: //www. tvtome. com/images/shows/4/8/40 -11946. jpg http: //www. coreywolfe. com/NOV%202004/mlp. jpg
White Light Green is reflected! Leaf Pigments Absorb Most Colors
Light: An Energy Waveform With Particle Properties Too amplitude brightness intensity Many metric units for different purposes We will use an easy-to-remember English unit: foot-candle 0 fc = darkness 100 fc = living room 1, 000 fc = CT winter day 10, 000 fc = June 21, noon, equator, 0 humidity
Photomorphogenesis light form Growth in Dark Etiolated origin process Growth in Light Normal Tall Short Thin Stocky White/Yellow Unexpanded leaves Preserves Green Expanded leaves Use reserves How deeply buried am I? Make Hay! Gravity! http: //botit. botany. wisc. edu: 16080/images/130/Tropisms/Etiolation/Etiolated_-_light_beans_MC_. jpg
Phototropism light growth toward act Darwin 1860 s Went: IAA IAA perception by zeaxanthin http: //www. ppdl. purdue. edu/ppdl/images/coleoptile 3. jpg transduction by IAA differential transport + growth response
Photosynthesis: Review and Expansion CO 2 + H 2 O light chlorophyll O 2 + CH 2 O Not 1 step…more like 50! Light Reactions: perhaps 25 steps ADP + NADP + H 2 O light chlorophyll Interdependent! Calvin Cycle Reactions: perhaps 25 steps ATP + NADPH 2 + CO 2 In sum: CO 2 + H 2 O light chlorophyll We have been hiding considerable truth from you! O 2 + NADPH 2 + ATP AKA: Dark Reactions CH 2 O + NADP + P O 2 + CH 2 O The light and Calvin cycle reactions are interdependent…no dark reactions!
What wavelengths of light drive photosynthesis? Photosynthetic Rate 100% 0 Action Spectrum green light reflected some still drives photosynthesis 400 visible spectrum 500 600 wavelength (nm) 700 nm Light beyond 700 nm has insufficient energy to drive photosynthesis
What intensities of light drive photosynthesis? 100% Reaction Rate Photosynthesis add to reserve grow reproduce Respiration Using reserves and may die 0 0 10 100 compensation point 1, 000 10, 000 fc Light Intensity (fc) The example plant shown here “breaks even” at an intensity we have in our homes…a house plant!
What intensities of light drive photosynthesis? 100% Reaction Rate Photosynthesis A 0 Photosynthesis B Respiration Shade tolerant plant dies in intense light! 0 10 100 compensation points 1, 000 10, 000 fc Light Intensity (fc) The second example plant shown here cannot survive in our homes…it is a sun-loving crop plant!
Where in a CT landscape is the light intensity the brightest…the longest? N Ferns Hosta Impatiens MOD. COOL MOIST Shade all Day! MOIST W AM Cool Shade PM Hot Sun House downspout Daisies HOT DRY! AM Cool Sun PM Warm Shade E downspout Sun all Day! MOD. Roses DRY! Petunias PM AM S
Where in the house is the light intensity the brightest…the longest? N Too Dark! Sun Lovers W House General Houseplants Shade Lovers African Violets Ferns Philodendrons E Greenhouse Effect! General Houseplants if Sheer Drapes PM AM S
USDA Hardiness Zones of “Lower 48” States Note: Willimantic is Zone 6
Where should plants be placed in a CT landscape for winter hardiness? Winter Wind N Exposed ZONE 4 MORE -5 UNIFORM WINDWARD INSULATEDShade all Day! COLD ZONE 5 -6 W AM Cool Shade PM Hot Sun House PM Warm Shade E ZONE 6 -7 ZONE 2 -3 PM AM Cool Sun Exposed Sun all Day! LEEWARD FREEZE INSULATED DRY snow profile S AM
Photoperiodism-Sensing Seasons by Daylength Short Day Plant Long Day Plant Noctoperiodism? Chrysanthemum Lettuce Poinsettia Long Night Plant? Short Night Plant? Summer (June 21) 16 hr 8 hr Winter (December 21) 8 hr vegetative flowering no change flowering 16 hr Night Interruption Spinach vegetative reversed 8 hr 10 sec W 8 hr vegetative flowering Day Interruption 10 sec 8 hr W Plants measure the length of the night…not the length of the day.
Photoperiodism-Does Light Wavelength Matter? Short Day Plant Control 8 hr 16 hr Long Day Plant flowering vegetative flowering vegetative Red 660 nm Interruption 8 hr 10 sec R 8 hr Far-Red 730 nm Interruption 8 hr 10 sec FR 8 hr Sequences Ending in Red 8 hr 10 sec each 8 hr R FR R 8 hr Sequences Ending in Far-Red 8 hr 10 sec each 8 hr FR R FR 8 hr Plants use Phytochrome to sense Night Light Status. Pr Pfr present for significant time in night blocks flowers. 660 nm 730 nm Pfr*
Photoperiod Applications: Chrysanthemum Story Poinsettia Story LDP Lettuce Problem: Equinoxes LDP Onions: Bermuda=11+ Sweet Spanish=15+ How long does light need to be on inside house? : Comp Point
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