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Roots
Unit 2 Plant Anatomy
Horticulture
What do roots do?

Purpose of roots:
 absorb
nutrients and moisture
 Anchor the plant in the soil
 Provide physical support for the
stem
 Serve as food storage organ
Types of Root Systems
Tap Root
 Fibrous Roots
 Adventitious roots
 others

Taproot

consist of one primary
root with few branches

fare well during droughts
because their roots go
deeper into the ground

Ex. Carrots, dandelions
Advantages and Disadvantages
of Taproots

Advantages
Penetrate deeper into the soil
 Obtain water from lower levels
 Anchor the plant


Disadvantages
Difficult to remove/harvest plants
 Do not stabilize the soil well

Fibrous Roots

roots consisting of lateral
roots near the surface of
the soil

responds quicker to
fluctuations in water and
nutrient levels because
they tend to be shallow
Advantages and Disadvantages
of Fibrous Roots

Advantages


Shallower, thus
respond more
quickly to
fertilization/irrigati
on
Stabilize the soil
better

Disadvantages


Less drought
resistant
Tend to get
exposed during
cultivation
Adventitious Roots
roots that appear at
locations other than
the normal root
system
 develop from aerial
portions of the stem
 ex. Prop roots on corn
plants

Adventitious roots
Root Anatomy
Terminology

Meristemtissue that produces new cells
 “Growth Tissue”


Apex
at the tip
 Meristematic Apex – at the tip of the
root where new cells grow

Anatomy
of the Root

Root is divided into sections: (bottom up)
Root cap
 Zone of Cell Division (Meristematic)
 Zone of elongation
 Zone of maturation/maturation


Root Cap
Protects the cells of the root
 Tough outer covering, pushes through
the soil

Meristematic Zone/ Zone of
cell division


located at the very tip of the root.
manufactures new cells through mitosis
(replication)
Zone of Elongation

these cells increase in size and push
the root through the soil
Zone of Maturation
cells undergo
changes in order to
become specific
tissues such as:



the epidermis
cortex,
vascular tissue
Other parts of the root and
functions.

Epidermis
 the outermost layer of
cells surrounding the
root
 responsible for the
absorption of water
and minerals that are
dissolved in water.
 root hairs develop here
Parts of the root

Cortex
 cells involved in the movement of water from
the epidermis to plant tissue and in food
storage

Vascular tissue
 conduct food and water
 located in the center of the root in dicots and
in bundles in monocots
 Xylem and Phloem: tube like structures that
carry nutrients to the rest of the plant
External Parts of the root

Root hairs
found along the main root
 performs much of the actual water and
mineral absorption.
 produced in the zone of maturation
