Root Zones and Tropisms
Dec 18, 2015
Root Zones and Tropisms
Root functions
•Anchors the plant•Absorbs water and minerals•Sends water and minerals
to the xylem
Parts of a root
Xylem carries water,Phloem carries food
Parts of a root
Root hairs- absorb water and minerals
Parts of a root
Area of Mitosis:growth
Parts of a root
Root Cap:Digs into ground
2 basic types of roots•1. Fibrous•Roots are tangled
together•Helps prevent
erosion
•2. TAPROOT•one long root, like
dandelion
What is it?• Spanish
moss
Root adaptations• A change that helps
an organism survive• 1. Aerial Roots• Grow above ground,
up in the air, suspended in a tree
• Usually in rain forest, can get water from air and rain
• Examples: Spanish moss, orchids
Aerial roots
Orchid
More Spanish moss
Why?• Tree canopy is 100-200 ft in air• Jungle floor is very dark
So an aerial root
• Can grow 150 ft up in the air• Without having to put down roots
into the soil• Can grow where the sunlight is
without competition from the trees
What is unique about this plant?
PROP roots
• Above ground roots, but most of root is underground
• Used to support a top heavy plant• Examples are corn and• Get ready, this is really really cool• Banyan tree• Ready?
All one treeroots grow out of branches to
support the weight
TROPISMS
• Response to a stimulus• Controlled by chemical hormones
called auxins
Hydrotropism
• Response to
•Water• Sketch:
Phototropism
• Response to
•Light• Sketch:
Geotropism or gravitotropism
• Response to
•Gravity