Unit 9C and 9D Lesson 5 Roots

1
Unit 9C and 9D Lesson 5 Roots

• Objectives to understand how roots absorb water,
  to describe how plants transport water from the
  roots to the leaves, to learn the two types of
  roots, and to learn how roots cells are adapted.
• Targets 8-10

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Its a Roots Life

• Roots have many purposes
• They anchor the plant so it doesnt blow away.
• They help to break up rocks in the soil.
• Their most important job is to absorb water and
  minerals from the soil.
• Q What do the plants need water for?
• A Photosynthesis

3
Types of Root

• Tap Roots this is a long root which goes deep
  into the soil. It is good in drier areas where
  the root may have to go deep underground for
  water.
• Fibrous roots these roots are thin and spread
  out near the surface of the ground. They are
  better in wetter areas because they can absorb
  lots of water before it seeps too deep into the
  soil.

Tap Root
Fibrous Root
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How do Roots Absorb Water?

• Roots have special cells called root hairs which
  absorb water from the soil.
• The root hair is very thin and long and serves to
  increase the surface area of the root.
• The water moves into the root by osmosis.
• This means that when the concentration of water
  in the soil is higher than in the root water will
  flow into the root.

Root Hairs
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How Does Water Move Up to the Leaves?

• Water moves up the stem of the plant for two
  reasons
• Water molecules tend to stick together. This
  means that, under the right circumstances, water
  can be pulled like a thread.
• Water evaporates through the stomata on the
  leaves of the plant. This is called
  transpiration and it creates a force which pulls
  water up the stem to the leaves.

Water Transport
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Work to Do

• Complete questions 1-8 page 87
• Homework
• Define the following keywords
• fibrous root, roots, mineral, tap root, stem,
  transpiration