Download Cacti Adaptations

#1
Roots
Roots are important to plants.
•They absorb water and minerals from the soil.
•They carry water and minerals to the stem.
•They help to anchor the plant in the soil.
•They store food and water for future use.
There are two major types of roots.
#2
Fibrous Roots
Taproots
Taproots
The taproot is the primary root that grows
down from the stem.
Cacti Adaptations -Taproots
Some cacti have a taproot. This taproot
allows the plant to store food and water
underground where they are away from the
hot, drying weather.
Taproot cacti are usually small because the
taproot is not able to hold up a lot of weight.
Fibrous Roots
Fibrous roots are small lateral roots that spread out just
below the soil surface.
Cacti Adaptations - Fibrous Roots
Most cacti have fibrous roots that spread
out widely from the plant and grow close
to the ground’s surface. Some prickly pear
roots spread 10 to 15 feet away from their
stems. This adaptation provides more roots
to absorb rain water.
Root Hairs
Smaller root hairs grow from the feeder roots. They increase
the surface area of the roots, which allows them to absorb
more nutrients and water.
#4
Cactus Adaptations - Root Hairs
When rains come, a cactus’ fibrous roots quickly grow
tiny root hairs to absorb water and nutrients.
This adaptation lets the roots collect even the smallest
amount of moisture from a light rainfall.
After the ground dries, the root hairs die and disappear.
This allows the cacti to live off their stored water, and they
will not have to use any moisture and energy
to keep the root hairs alive.
Cacti Root Adaptations
Some larger columnar cacti will have
both fibrous roots and a taproot.
The taproot helps anchor the heavy plant and also allows
it to reach deeper water supplies.
The fibrous roots are spread out widely so they can
#3&4
collect surface water when it rains.
#2a&b
Cacti Adaptations - Why is a Cactus a Special Succulent?
The one thing that separates cacti from the other succulents is
the way their spines grow. Cacti are the only succulents that
grow their spines from areoles. New growth (flowers, segments,
spines) of the cacti comes from the areoles. Some cacti will
#5
have leaves, but they soon fall off.
Cacti Adaptations - Why is a Cactus a Special Succulent?
Leaves form on a new prickly pear pad.
These leaves will soon fall off.
Remember:
All cacti are succulents, but not all succulents are cacti.
To be a cactus, the plant has to have areoles.
Cactus Adaptations – Spines (Leaves)
#6 Cacti grow spines instead of leaves because spines don’t
lose water like the leaves of other plants.
Cactus Adaptations – Spines (Leaves)
#7
Spines also protect the plant against animals.
The cactus basically is saying,
"How much pain are you willing to endure to get a drink
from me?"
Cactus Adaptations – Spines (Leaves)
White dense spines also help to reflect light away from the
cactus stem, which can lower the temperature of the stem.
#9a
Cacti Adaptations - Spines (Leaves)
#9b
Cacti spines also help keep the plants cooler by
casting shade on them.
Cacti Adaptations - Spines, Ribs, and Shape
The spines, ribs, and round shape of some of the cacti combine
to make sure that no single part of the plant
receives the brunt of the hot sun all day long.