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The Importance of Plants Without plants, life on earth could not exist Plants are the primary source of food for humans and animals
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Plant Anatomy
Unit 1Chapter 6Lesson 1
The Importance of Plants
• Without plants, life on earth could not exist• Plants are the primary source of food for
humans and animals
The Importance of Plants cont.
• Plants also:– Provide oxygen– Provide shade– Supply us with medicines– Renew the air– Slow down the wind– Hold soil in place– Are a home for wildlife– Furnish building materials and fuel
Parts of the Plant
• Most plants are made up of four basic parts:– Leaves– Stems– Roots– Flowers (these later
become fruit or seeds)
Roots
• Usually underground – not visible• Functions:– Anchor the plant and hold it upright*– Absorb water and minerals from the soil & conduct
them to the stem*– Store large quantities of plant food*– Propagate or reproduce in some plants
* = essential to all plants
Roots on the Inside
• Very similar to a stem• Older roots of shrubs &
trees have:– Phloem on the outside
(old phloem is bark)– Cambium layer– Xylem (wood) on the
inside
• Phloem– Carries manufactured food down to the root for food storage
• Xylem – Carries water and minerals up to the stem
Roots on the Outside• Different from a stem• On a stem, the terminal bud initiates growth• On a root, the root cap initiates growth• Root cap continuously
makes new cells that protect the root as it pushes into the soil
Root External Structure
• Behind the root cap are root hairs
• Root hairs become side roots that branch out as the root grows older
• Absorb moisture and minerals which are conducted up to the larger roots and the stem
Roots as Crops
• Cash crops– Carrots– Beets– Radishes– Sweet Potatoes
Root Propagation
• Plants with tuberous roots:– Dahlia– Peony– Sweet Potato
• Are propagated by separating the root clump or by rooting spouts from the root
Types of Root Systems
Fibrous Root System vs. Tap Root System
• Which root system is easier to transplant? Fibrous roots or tap roots?
• Answer: Fibrous roots
• Why? • Because when plants
are dug up out of the ground, a greater % of the fibrous roots system is saved.
• If a root loses to many root hairs while being transplanted, the plant will die.
• Larger roots only conduct & store water, nutrients, and food
• Root hairs absorb moisture from the ground
Important “Root”words
• Root System– All of the root parts of a single plant collectively
• Primary Root– First root sent from a germinating seed– Absorbs water and nutrients for growing seedling– Anchors seedling in the ground
• Secondary Roots– Small branches that form off of the primary root
Important “Root”words
• Root cap– Group of cells at the end of a root that protect it
from the coarse soil as it pushes through to grow• Adventitious root– Roots that begin growth from a stem or leaf– Commonly found on corn plants
• Basal rooter– Plants that will produce roots at the base of the
stem when a cutting is taken
Important “Root”words
• Root tuber– Enlarged food-storage root with adventitious
shoots that develop– These shoots produce adventitious roots to
produce a new plant