Ch. 4 Lesson 4How do plants grow?

““mile a minute plant”mile a minute plant”-can grow up to 1 foot per day-can grow up to 1 foot per day

tropisms• ways that plants change their direction of growth in response to environment

gravitropism•roots grow downward b/c of gravity

phototropism• plant’s reaction to light

• stem grows toward light

thigmotropism

•plant’s growth in response to touching an object

growth hormone• chemical that affects

plant growth

• can make cells grow larger

• cells may also look larger b/c vacuoles fill w/ water

gravitropismgravitropism

Name that Name that tropism!tropism!

Name that tropism!Name that tropism!

phototropismphototropism

Name that tropism!Name that tropism!

phototropismphototropism

Name that tropism!Name that tropism!

phototropism & gravitropismphototropism & gravitropism

Name that tropism!Name that tropism!

thigmotropismthigmotropism

Tropisms in our neighborhood

Plant name

Location

Type of tropism

Sketch or describe tropism