Plants Move

TROPISMis a biological phenomenon, indicating growth or turning movement a plant makes in response to an environmental stimulus

Tropismhttp://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/tropisms.html

Phototropism

Movement of plants toward light to maximize amount of sun for photosynthesis to make their food.

Heliotropism http://www.youtube.com/watch?NR=1&v=KQOC_bPrqFs&safety_mode=true&persist_safety_mode=1

Gravitropism

http://www.youtube.com/watch?v=mYZXax8V_L0&feature=related&safety_mode=true&persist_safety_mode=1

Movement of plants in response to gravityPositive is toward gravity (roots)Negative is away from gravity (shoot: stems and leaves)

Hydrotropism

http://virtualastronaut.tietronix.com/textonly/act25/text-plants.html

Movement by plants toward water.

Seen in roots “searching” and growing toward water which is needed for photosynthesis and to support cell structure.

Thigmotropism

http://www.youtube.com/watch?v=8HeedWWe6VA&feature=related&safety_mode=true&persist_safety_mode=1

Plants moving in response to touch.

Seen in vine plants as they wrap around other plants or structures to support leaves as they grow higher and higher to reach the sun to make more food (photosynthesis).

Plant Tropisms

Tropism: the way a plant grows in response to stimuli in the environment.1) Phototropism: growth response to

light Plants bend towards light

2) Gravitrophism: growth response to gravity plant roots grow down with gravity,

shoots (stems) grow up against gravity and out of the soil.

3) Thigmotropism: growth response to touch vines grow up around trees, Venus

flytrap closes when leaves are touched

Slide # 23

A.

What type of tropism is shown in these pictures?

DC

B

FE.

Slide # 23

Gravitropism

What type of tropism is shown in these pictures?

ThigmotropismPhototropism

Phototropism

ThigmotropismGravitropism

ReviewAdaptations for Life on Land

Leaves – absorb energy from sun; centers for photosynthesis and gas exchange

Roots – anchor plants; absorb H2O & minerals from soil

Stems – hold plant upright; transport food & water along the plant

Flowers – produce sperm & eggs for reproduction in angiosperms

Seeds – protect embryo from damage and water loss; dispersed away from parent plant

Fruits – method of seed dispersal in flowering plants