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Light. The Source of all Biological Energy Trapped in Photosynthesis Used to determine Seasons. Light: An Energy Waveform With Particle Properties Too. wavelength. violet. blue. green. yellow. orange. red. 400 500 600 700 nm.

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Presentation Transcript
light

Light

The Source of all Biological Energy

Trapped in Photosynthesis

Used to determine Seasons

slide2

Light: An Energy Waveform With Particle Properties Too

wavelength

violet

blue

green

yellow

orange

red

400 500 600 700 nm

wavelength (nm)

10-9 meter

0.000000001 meter!

slide3

Light: An Energy Waveform With Particle Properties Too

wavelength

visible spectrum

400 500 600 700 nm

wavelength (nm)

10-9 meter

0.000000001 meter!

slide4

White light: all the colors humans can see at once

http://www.alanbauer.com/photogallery/Water/Rainbow%20over%20Case%20Inlet-Horz.jpg

slide5

http://www.chez.com/uvinnovation/site/images/introduction/apple_logo.gifhttp://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.net/websmurfclub/images/pinsmurfoncloudrainbow.jpg

http://www.tvtome.com/images/shows/4/8/40-11946.jpg

http://www.coreywolfe.com/NOV%202004/mlp.jpg

slide6

White Light

Green is reflected!

Leaf Pigments Absorb Most Colors

slide7

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

slide8

Photomorphogenesis

light

form

origin

process

Growth in Dark

Etiolated

Growth in Light

Normal

Short

Stocky

Green

Expanded leaves

Usereserves

Tall

Thin

White/Yellow

Unexpanded leaves

Preserve reserves

How deeply buried am I?

Make Hay!Gravity!

http://botit.botany.wisc.edu:16080/images/130/Tropisms/Etiolation/Etiolated_-_light_beans_MC_.jpg

slide9

Phototropism

IAA

IAA

Darwin 1860s

light growth toward act

Went: IAA

transduction by IAA differential transport

perception by zeaxanthin

growth response

+

http://www.ppdl.purdue.edu/ppdl/images/coleoptile3.jpg

slide10

Photosynthesis: Review and Expansion

We have been hiding considerable truth from you!

Not 1 step…more like 50!

light

CO2 + H2O

O2 + CH2O

chlorophyll

Light Reactions: perhaps 25 steps

light

ADP + P +

NADP +

H2O

O2

+ NADPH2

+ ATP

chlorophyll

Interdependent!

Calvin Cycle Reactions: perhaps 25 steps

AKA: Dark Reactions

ATP +

NADPH2 +

CO2

CH2O

+ NADP

+ ADP + P

light

In sum:

CO2 + H2O

O2 + CH2O

chlorophyll

The light and Calvin cycle reactions are interdependent…no dark reactions!

slide11

100%

Photosynthetic Rate

0

What wavelengths of light drive photosynthesis?

Action Spectrum

green light reflected

some still drives photosynthesis

visible spectrum

400 500 600 700 nm

wavelength (nm)

Light beyond 700 nm has insufficient energy to drive photosynthesis

slide12

100%

Reaction Rate

0

0 10 100 1,000 10,000 fc

Light Intensity (fc)

What intensities of light drive photosynthesis?

Photosynthesis

add to reserve

grow

reproduce

Respiration

Using reserves and may die

compensation point

The example plant shown here “breaks even” at an intensity we have in our homes…a house plant!

slide13

100%

Reaction Rate

0

0 10 100 1,000 10,000 fc

Light Intensity (fc)

What intensities of light drive photosynthesis?

Photosynthesis A

Photosynthesis B

Respiration

Shade tolerant plant dies in intense light!

compensation points

The second example plant shown here cannot survive in our homes…it is a sun-loving crop plant!

slide14

N

W

E

House

downspout

downspout

PM

AM

S

Where in a CT landscape is the light intensity the brightest…the longest?

Ferns

Hosta

Impatiens

MOD. MOIST

COOL MOIST

Shade all Day!

AM Cool Shade

PM Hot Sun

AM Cool Sun

PM Warm Shade

Sun all Day!

HOT DRY!

MOD. DRY!

Daisies

Roses

Petunias

slide15

N

W

E

House

PM

AM

S

Where in the house is the light intensity the brightest…the longest?

Too Dark!

Sun Lovers

Shade Lovers

African Violets

Ferns

Philodendrons

General Houseplants

Greenhouse Effect!

General Houseplants if Sheer Drapes

slide17

Winter Wind

N

W

E

House

snow profile

PM

AM

S

Where should plants be placed in a CT landscape for winter hardiness?

Exposed MORE UNIFORM COLD

ZONE 4-5

WINDWARD INSULATED

Shade all Day!

ZONE 5-6

AM Cool Shade

PM Hot Sun

AM Cool Sun

PM Warm Shade

ZONE 6-7

ZONE 2-3

Sun all Day!

ExposedFREEZE DRY

LEEWARD INSULATED

slide18

Short Day Plant

Long Day Plant

Chrysanthemum

Poinsettia

Lettuce

Spinach

Summer (June 21)

vegetative

flowering

16 hr

8 hr

no change

Winter (December 21)

flowering

vegetative

8 hr

16 hr

reversed

Night Interruption

10 sec

vegetative

flowering

8 hr

8 hr

W

8 hr

Day Interruption

10 sec

vegetative

flowering

8 hr

W

8 hr

8 hr

Photoperiodism-Sensing Seasons by Daylength

Noctoperiodism?

Long Night Plant?

Short Night Plant?

Plants measure the length of the night…not the length of the day.

slide19

Red 660nm Interruption

10 sec

8 hr

8 hr

R

8 hr

Control

Far-Red 730nm Interruption

10 sec

flowering

flowering

flowering

vegetative

vegetative

vegetative

8 hr

16 hr

8 hr

8 hr

FR

8 hr

Sequences Ending in Red

10 sec each

vegetative

vegetative

flowering

flowering

8 hr

8 hr

R

FR

8 hr

R

Sequences Ending in Far-Red

10 sec each

8 hr

8 hr

FR

R

8 hr

FR

Photoperiodism-Does Light Wavelength Matter?

Short Day Plant

Long Day Plant

660 nm

Plants use Phytochrome to sense Night Light Status.

*

Pr

Pfr

Pfr present for significant time in night blocks flowers.

730 nm

slide20

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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