Presentation on theme: "Light The Source of all Biological Energy Trapped in Photosynthesis"— Presentation transcript:
1 Light The Source of all Biological Energy Trapped in Photosynthesis Used to determine Seasons
2 Light: An Energy Waveform With Particle Properties Too wavelengthvioletbluegreenyelloworangerednmwavelength (nm)10-9 metermeter!
3 Light: An Energy Waveform With Particle Properties Too wavelengthvisible spectrumnmwavelength (nm)10-9 metermeter!
4 White light: all the colors humans can see at once
5 Which side of our brains are we using? Which side of our brains are we using?
6 Leaf Pigments Absorb Most Colors White LightGreen is reflected!Leaf Pigments Absorb Most Colors
7 Light: An Energy Waveform With Particle Properties Too amplitudebrightnessintensityMany metric units for different purposesWe will use an easy-to-remember English unit: foot-candle0 fc = darkness100 fc = living room1,000 fc = CT winter day10,000 fc = June 21, noon, equator, 0 humidity
8 Photomorphogenesis light form origin process Growth in Dark Etiolated Growth in LightNormalTallThinWhite/YellowUnexpanded leavesPreserve reservesShortStockyGreenExpanded leavesUse reservesHow deeply buried am I?Make Hay! Gravity!
9 Phototropism Darwin 1860s Went: IAA light growth toward actWent: IAAtransduction by IAA differential transportIAAIAAperception by zeaxanthingrowth response+
10 Photosynthesis: Review and Expansion We have been hiding considerable truth from you!Not 1 step…more like 50!lightCO2 + H2OO2 + CH2OchlorophyllLight Reactions: perhaps 25 stepslightADP + P +NADP +H2OO2+ NADPH2+ ATPchlorophyllInterdependent!Calvin Cycle Reactions: perhaps 25 stepsAKA: Dark ReactionsATP +NADPH2 +CO2CH2O+ NADP+ ADP + PlightIn sum:CO2 + H2OO2 + CH2OchlorophyllThe light and Calvin cycle reactions are interdependent…no dark reactions!
11 What wavelengths of light drive photosynthesis? Photosynthetic Rate100%Action Spectrumgreen light reflectedsome still drives photosynthesisvisible spectrumnmwavelength (nm)Light beyond 700 nm has insufficient energy to drive photosynthesis
12 What intensities of light drive photosynthesis? Reaction Rate100%Photosynthesisadd to reservegrowreproduceRespirationUsing reserves and may dieLight Intensity (fc), ,000 fccompensation pointThe example plant shown here “breaks even” at an intensity we have in our homes…a house plant!
13 What intensities of light drive photosynthesis? Reaction Rate100%Photosynthesis APhotosynthesis BRespirationShade tolerant plant dies in intense light!Light Intensity (fc), ,000 fccompensation pointsThe second example plant shown here cannot survive in our homes…it is a sun-loving crop plant!
14 Where in a CT landscape is the light intensity the brightest…the longest? FernsHostaImpatiensMOD. MOISTCOOL MOISTShade all Day!downspoutHouseAM Cool ShadePM Hot SunAM Cool SunPM Warm ShadeSun all Day!HOT DRY!MOD. DRY!DaisiesRosesPetuniasPMAM
15 General Houseplants if Sheer Drapes Where in the house is the light intensity the brightest…the longest?NWESHouseToo Dark!Sun LoversShade LoversAfrican VioletsFernsPhilodendronsGeneral HouseplantsGreenhouse Effect!General Houseplants if Sheer DrapesPMAM
16 USDA Hardiness Zones of “Lower 48” States Note: Willimantic is Zone 6
17 Exposed MORE UNIFORM COLD Where should plants be placed in a CT landscape for winter hardiness?Winter WindNWESExposed MORE UNIFORM COLDsnow profileZONE 4-5WINDWARD INSULATEDShade all Day!ZONE 5-6HouseAM Cool ShadePM Hot SunAM Cool SunPM Warm ShadeZONE 6-7ZONE 2-3Sun all Day!ExposedFREEZE DRYLEEWARD INSULATEDPMAM
18 Plants measure the length of the night…not the length of the day. Photoperiodism-Sensing Seasons by DaylengthNoctoperiodism?Short Day PlantChrysanthemumPoinsettiaLong Day PlantLettuceSpinachLong Night Plant?Short Night Plant?16 hr8 hrSummer (June 21)vegetativefloweringno change16 hr8 hrWinter (December 21)floweringvegetativereversed8 hrW10 secNight Interruptionvegetativeflowering8 hrW10 secDay InterruptionvegetativefloweringPlants measure the length of the night…not the length of the day.
19 Photoperiodism-Does Light Wavelength Matter? Short Day PlantLong Day Plant16 hr8 hrControlfloweringvegetative8 hrR10 secRed 660nm Interruptionvegetativeflowering8 hrFR10 secFar-Red 730nm Interruptionfloweringvegetative8 hrR10 sec eachSequences Ending in RedFRvegetativeflowering8 hrFR10 sec eachSequences Ending in Far-RedRfloweringvegetative660 nmPlants use Phytochrome to sense Night Light Status.*PrPfrPfr present for significant time in night blocks flowers.730 nm
20 Photoperiod Applications: Chrysanthemum StoryPoinsettia StoryLDP Lettuce Problem: EquinoxesLDP Onions: Bermuda=11+ Sweet Spanish=15+How long does light need to be on inside house?: Comp Point