Transcript Notes Chapter #20

Chapter #20
Plant
Support
and
Transport
Chapter 20.1
• 2 stem types
1. Woody- a non green stem grows thick
and hard bark. (Trees)
2. Herbaceous- are soft, green stems.
Grow no taller than meters. Have few
xylem cells. (Flowers and grass)
Woody Stems
• 5 Cell layers
1. Cork- outer layer made of
dead cells and protects
the stem from insects,
disease and water loss.
2. Cortex- stores food.
3. Phloem cells- move food
4. Cambium- thin layer of
cells that makes new
phloem and xylem cells.
5. Layers 1-4 make up the
Bark
6. Xylem- takes up water.
Cork
Cortex
• Terminal bud- is the bud at the tip of a stem,
responsible for the plants growth in length.
• Lateral bud- gives rise to new branches, leaves
or flowers.
• Annual ring- cambium
forms a ring of new
xylem cells each year.
Each ring is made up of
a dark and light band.
• Light rings form in Spring
when there is plenty of
rain and growth is rapid.
• Dark rings form in
Summer when there is
less rain and growth is
slower. They look dark
because the xylem tubes
are close together.
Oldest
wood
found in
center
Chapter 20.2
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Roots take up water
Water roots stem leaves
stomata
Leaves make food
Food leaves stem
roots
Water storage in herbaceous stems is
used to prevent wilting. Water acts like a
skeleton.
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1.
2.
3.
4.
5.
•
Plants store sugar as starch.
Plants use most of their stored food for new
growth in the spring (leaves and flowers).
Stem are used for:
Wood
Dollar bills
Paper
Food packets
Food (Cauliflower and Broccoli)
Sap liquid that flows up the xylem.
Chapter 20.3
• Two types of Roots
1. Taproot- large, single root with smaller side roots. Stores
food. Example: beets, carrots, turnips, dandelions.
2. Fibrous roots- are many branched roots that grow in
clusters. No main, large root.
Root layers
1. Root hairs- are threadlike
cells of the epidermis that
absorb water and
minerals.
2. Epidermis- protects
3. Cortex- stores food
4. Endodermis- waxy cells
that help reduce water
loss.
5. Xylem- carry water
6. Phloem- carry food
7. Cambium- makes
new xylem and phloem
Root hairs
Endodermis
Xylem
Cambium
Phloem
Cortex
Epidermis
• The first root of a new plant is its primary
root other roots are called secondary
roots.
• Most roots keep growing as long as the
plant lives.
• New cells are added to the END of a root,
that is why they grow DOWN.
Chapter 20.4
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1.
2.
3.
4.
5.
Plants get needed materials (water and
minerals) for growth through their roots.
Plants would die without roots.
Root hairs increase surface area.
Roots are used for:
Food
Tea
Perfumes
Medicines
Reduce erosion
Roots can cause damage to underground pipes.
Jobs of
roots
Absorption
Water
Storage
minerals
Food
Used for new
growing season
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“Tree”. December 19, 2006.
http://www.cs.cmu.edu/afs/cs/misc/rayshade/all_mach/omega/doc/Example
s/jpg/tree.jpg
“Stem Layers”. December 19, 2006.
http://www.ju.edu.jo/ecourse/Basics%20of%20Fruit%20Trees/Material/Lect3-Internal%20Structure%20of%20the%20Fruit%20Tree_files/image004.jpg
“Tree Rings”. December 19, 2006.
http://volcanoes.usgs.gov/Imgs/Gif/Assess/TreeRing.gif
“Buds”. December 19, 2006. http://www.infovisual.info/01/004_en.html
• “Roots”. December 20, 2006.
http://www.kidsgardening.com/onlinecourse/Diagrams/c5/c5-1root.gif
• “Root layers”. December 20, 2006.
http://www.campbell.edu/faculty/metz/Biology202/images/botany%20diagra
ms/root-dc-labeled.jpg