Plant response to the environment. Plants food source medicines biofuels

Plant response to the environment

Plants

•food source

•medicines

•biofuels

www.naai.moldova.md

Unique Mechanisms

•Grow indeterminately

•Endure climate

•Obtain nutrients locally

•Defend self without running away

Plant response to the environment

Environmental trigger: light, gravity, touch

response: movement

Environmental trigger: herbivores

response: communication

Darwin•The Power of Movement in Plants (1881)

•http://javalab.cs.uni-bonn.de/research/darwin/images/darwin.jpg

Why do plants need to move?

gather nutrients

optimize light exposure

Movement responses

Light

courtesy: Roger Hangarter, Plants in Motion

http://plantsinmotion.bio.indiana.edu/plantmotion/starthere.html

QuickTime™ and aSorenson Video decompressorare needed to see this picture.

Plant cells have an array of light receptors

phyphy

sun

plant cell

movementtowards

light

germination

Some plants require light to germinate

CB 39.18

darklight,

then dark

germination!

PHYTOCHROMEPHYTOCHROME

UV BLUE RED FAR-RED

PHYTOCHROME

PFRPR

TRANSLOCATED INTO

NUCLEUS

RED LIGHT

FAR-REDLIGHT

Red light = ON

Far Red light = OFF

phy

phy

pRform

pFRform

Some plants require light to germinate

CB 39.18

phy inactive phy active phy inactive

Sunlight contains both r and fr light

R absorbed

lowR:FRratio

highR:FRratio

Gravity

courtesy: Roger Hangarter, Plants in Motion

http://plantsinmotion.bio.indiana.edu/plantmotion/starthere.html

QuickTime™ and aSorenson Video decompressorare needed to see this picture.

Starch grains detect vector of gravity

Blancaflor and Masson (2003) Plant Physiology 133:1677Kiss (2006) PNAS

103:829

Shoots

Growth occurs on ‘bottom’ side

shoots

Touch

touched not touched

Touch

courtesy: Roger Hangarter, Plants in Motion

FIRE

http://plantsinmotion.bio.indiana.edu/plantmotion/starthere.html

QuickTime™ and aH.263 decompressor

are needed to see this picture.

Touch

courtesy: Roger Hangarter, Plants in Motion

http://plantsinmotion.bio.indiana.edu/plantmotion/starthere.html

Changes in cell size close or open leaves

Interactions

• Light, gravity and touch

Wind

G

Light, gravity and touchLight

perceived by light receptorsblue light - movement towards lightred/far red (phytochromes) - germination

Gravityperceived by falling starch grainscells growth on one side bends shoot up

Touchelectrochemical gradient (like nerves in animals)changes cell size closes/opens leaves

Communication

www.panoptikum.net

Plants know when they are being

chewed on!

Insect saliva •

lets plant know which insect is attacking

Alerts othersJasmonic acid

ProteaseInhibitors

ProteaseInhibitors

http://www.geocities.com/brisbane_parawasps/images/Parasi3.jpg

Calls reinforcements“The enemy of my enemy is a friend of mine!”

SummaryMovement responses

triggers: light, gravity, touch

changes in cell length or cell size

Communication responses

triggers: herbivores

release of volatile chemicals (Jasmonic acid)