Topic 2: Plant Structures and
Adaptations
 Plants have specific structures to help them adapt to their
environments
 Plants are made of three main systems  parts with multiple
smaller parts. They are the
systems.
Roots
 Found underground
 Main roles are to absorb minerals and nutrients in the soil, absorb
water in the soil, anchors the plants from being blown or washed
away, store food in case of scarcity
 Have tiny, fine
whose main role is to increase the root
system’s surface area for better absorption of water and nutrients.
a.
 some plants have a single, prominent taproot that often
dig deep into the ground. Ex) carrots, dandelions, large desert
plants
 a network of
similar-sized roots that can quickly
soak up moisture. Ex) cacti to
absorb water quickly before the
water drains away in the desert
sands.

 some plants where
the main parts eaten are the roots
where much of the nutrients are
found. Ex)carrots, beets, turnips,
radishes, parsnips.
**Potatoes are not roots. They are
(special type of
underground stems)
b.
Water inside plant cells is what
keeps them firm and maintains their
shapes. Without water, plants go
limp, soft and eventually die. Water
also dissolves minerals in the soil for
osmosis into the roots.
 One of the most important
function of roots is absorption of
nutrients and water. Roots absorb
water and nutrients through:
a.
 tendency for
particles to become evenly
distributed by moving from areas
of high concentration to an area
of lower concentration
b.
 is one type of
diffusion where only certain
types of particles such as water
and specific nutrients are
allowed to pass through a barrier
that is
(also called semi-permeable).
Other particles not needed by
the plant is kept out.
Shoot
 The visible parts of plants USUALLY
above the ground
 consists of the
(parts of some
stems are underground) and
 Woody tree stems (the tree trunk)
consist of
a.
dead wood in the centre.
The oldest part and also gives the tree
its strength
b.
carries water and nutrients
Memorize the layers of the tree and
up from roots to leaves
c.
 growing part of tree that their functions on page 108!
makes new xylem and phloem cells.
They form the tree rings
d.
cells that carry the sugars
Mr. Dang
made in the leaves downwards to the
standing inside
roots and stem.
the tree trunk of
e.
 rough, outer woody skin that
the Big Hollow
prevents dehydration, the
Tree in Stanley
environment, pests, and insulates the
tree
Park, Vancouver.
It’s a giant cedar
tree.
 Roles of the stem:
a. Transport nutrients and water up the
, sugars down the
cells
b. Support the plant so it doesn’t fall over
and also it reaches up high for light
c. Food storage- many plants store extra
food in specialized stems, some of which
is underground. But they are NOT roots!
Ex) potatoes and yams are tubers. Sugar
canes store sugars in their stems.
 Types of stems:
a.
– roots and new baby plants
grow at the end of horizontal runners.
Ex) strawberry and spider plants
b.
- special bulbs like tulips, gladioli,
daffodil flowers, onions, garlic
c.
-horizontal stems that allow the
plant to spread under ground. Ex)
cattails, raspberry
d.
- prickly pear cactus have
special flat stems so that one side faces
the sun for maximum light, the other side
is in shade to stay cool.
 Roles of leaves:
a. Some are specially shaped to prevent water loss.
Ex) coniferous tree needles
b. Most important role is to make food by
 the process of making sugars
by combining water with CO2 (g) and using light.
Memorize this equation. Note how each part is
written:
carbon dioxide gas is absorbed into the leaves
through tiny holes called
(singular –
stoma) and reacts with the water (that was
absorbed in the roots and carried up by the
xylem) inside the special structures called
, a pigment (a chemical that absorbs and
reflects certain colors) called
reacts
with light to break apart H20 and CO2 and forms
(a type of sugar that plants use for
energy) and O2.
O2 is released into the air through the stomata.
Plant cells with clearly
visible chloroplasts
containing chlorophyll
for photosynthesis

A single stoma
opening with 2
guard cells on
each side
Guard
cells
on each side of the
stomata control the opening and
closing of the stomata.
 During dry times, the guard cells
tighten the stomata opening to
prevent water loss

is the reverse of
photosynthesis. All animal cells
and plant cells (only at night)
undergo respiration.
Memorize this equation too.