Transcript Roots and Stems - Cloudfront.net

Roots and
Stems
Functions of Roots
Anchor the plant
Absorb water and nutrients from the
soil and transports them to the stems and
leaves
Store food for the plant
Help prevent soil erosion
Parts of a Root System
Primary Roots
 Grow from the hypocotyl part of the seed
embryo
Secondary Roots
 Branch off of the primary root
Root Hairs
 Hair-like extensions that make their way through the openings
between soil particles
 Water and nutrients enter the root hairs and travel up the
secondary and primary roots to the stems and leaves
Parts of a Root System
Primary Root
Secondary
Roots
Root Hairs
Taproot
One large root with
smaller secondary roots
attached to it
They penetrate deep
into the soil
Examples: carrot,
dandelion, oak trees
Fleshy Taproot

Acts as a food storage area
of the plant

Examples: carrots, turnips,
beets
Fibrous Root
 No recognizable primary
root
 Lots of fine, thread-like roots
of the same size
 Originate at the base of the
stem
 Spread near the surface of
the soil
 Examples:
WHICH ONE?
grasses, shrubs
Balance Between
Roots and Stems
 Roots supply water and minerals to
shoots, while shoots supply food to roots.
 Hormones normally balance growth of roots
and shoots.
 Roots produce cytokinin, which travels to
shoots and promotes bud growth.
 Shoots produce auxin, which travels to roots
and promotes root growth.
Functions of Stems
 Transports materials up and down the
plant through the vascular system
 Consists of xylem and phloem tissue
 Young stems have vascular bundles, which consist of both
xylem and phloem
 Woody stems have a vascular cylinder in which the outer
portion is the phloem and the inner portion is the xylem
Xylem Tissue
 Moves water and nutrients UPward from the
roots to the stems and leaves
Phloem Tissue
 Moves water and nutrients DOWNward from
the stems and leaves to the roots
Other Functions of Stems
 Provide physical support for leaves, fruit and
flowers
 Store food (Ex. Onions, garlic, potatoes)
 Green stems have chlorophyll in them and
conduct minor photosynthesis
 Capable of reproduction
 Help establish tendrils which aid
climbing plants
Types of Stems
 Herbaceous – soft tissue
that bends
(ex: houseplants)
 Woody – brittle,
non-bendable, bark-like tissue
(ex: trees, shrubs)