Transcript Plants

WHAT DO YOU KNOW ABOUT PLANTS?
Sketch this plant
in your notebook
and label the
parts of the plant
that you can
identify.
WHAT DO YOU KNOW ABOUT PLANTS?
PLANTS HAVE ORGANS TOO!
What is the
function of each
of these parts of
the plant?
WHAT DO YOU KNOW ABOUT PLANTS?
PLANTS HAVE ORGANS TOO!
• anchors the plant to the
ground
• absorbs water and nutrients
(minerals) from the soil
• provides structure and
support
• positions the leaves to collect
sunlight
• traps energy from the sun to
make “food”
• site of gas exchange (carbon
dioxide and oxygen)
• contains the reproductive
structures
WHAT DO YOU KNOW ABOUT PLANTS?
PLANTS HAVE ORGAN SYSTEMS TOO!
The Shoots System
• parts of the plant above
ground
• stems, leaves, flowers
The Roots System
• part of the plant below
ground
The Reproductive System
• Flowers/cones
Fern
Golden Barrel Cactus
Hydnora africana
Spanish Moss
Wolffia
angusta
Does this plant
have all four
plant structures?
Where are the
leaves? the
stem?
Golden Barrel Cactus
Why are the leaves and stem shaped the way they are?
Does this plant
have all four
plant structures?
Fern
Do these plants have all four plant
structures?
Do they
flower?
Spanish Moss
Where are the
roots?
Does this plant
have all four
plant structures?
Wolffia angusta: each speck is an individual plant!
In what
environment do
you think these
plants live?
Does this plant
have all four
plant structures?
Hydnora africana
SO WHAT REALLY MAKES A PLANT
A PLANT!?!
DNA
ribosomes
large, central vacuole
nucleus
plasma
membrane
cell wall
cytoplasm
chloroplast
WHAT DO PLANTS NEED TO
SURVIVE?
WHAT EXACTLY DO PLANTS NEED
TO SURVIVE?
WHAT EXACTLY DO PLANTS NEED
TO SURVIVE?
What nutrients do plants need?
• Nitrogen, phosphorus,
potassium, calcium,
magnesium, sulfur
Where do they come from?
• The soil…they get dissolved
in the water absorbed by the
plant.
WHAT EXACTLY DO PLANTS NEED
TO SURVIVE?
SO HOW DO PLANTS GET ALL OF
THESE THINGS?
NONVASCULAR PLANTS


The first plants to evolve were very simple, very
small – they did not have roots or stems!
In what type of environment do you think they
must have lived? Why?
WET!

Why do you think they had to stay small?
Cannot transport water,
food, or nutrients so all cells
must be able to absorb
water directly and make
what they need!
SO HOW DO WE HAVE BIG, TALL,
COMPLEX PLANTS THAT DO NOT LIVE
IN WATER?!?!
WHAT WAS THE GREATEST
CHALLENGE TO PLANTS AS THEY
BEGIN TO MOVE ONTO LAND?
VASCULAR PLANTS

Plants evolved a way to transport water and
nutrients and therefore could grow much larger,
with cells far away from the water source.

This transport system
(the vascular system)
is made up of
specialized plant cells,
called vascular tissue.
Vascular
System
Vascular
Tissues
Plant
Cells
Vascular
Plant

Vascular tissues transport materials from one part of the plant to
another and spans both the roots and shoots systems.
Shoots
System
Roots
System

Vascular tissues transport materials from one part of the plant to
another and spans both the roots and shoots systems.

Xylem –transports water and minerals upward from the roots to the
shoots

Phloem –transports nutrients (food/sugars) from the leaves where
food is made to the rest of the plant
top/leaves
This vascular system
allowed for the
evolution of….
bigger, more complex
plants that could live
on land!
bottom/roots
HOW DOES WATER GET INTO THE
PLANT?
WHAT MAKES WATER TRAVEL
UPWARD, AGAINST GRAVITY?
HOW DOES THE WATER GET
INTO THE XYLEM?
By osmosis through the root cells

Osmosis – movement of
water from high concentration
to low concentration. Water
moves into the root cells
because there is less water in
the roots than in the soil.
H2O
PATH OF WATER ENTERING
A ROOT
HOW DOES THE XYLEM WORK?

Once water has entered the xylem, it continues to
“want” to move upward because of osmosis.
But how can it move against gravity?!?

the tendency for water
to rise within a thin narrow tube due to adhesion and
cohesion! (like a straw!)
What does adhesion and cohesion mean?!?
COHESION
 Cohesion – water
sticks to water because
of hydrogen bonds
 In plants, each water
molecule pulls on the
next water molecule and
on and on until the water
pulls up the xylem!
ADHESION
 Adhesion – the attraction between unlike
molecules
 In plants, this is water sticking to other
substances, like the walls of the xylem
 So together, cohesion and adhesion allow water
to stick together and stick to the sides of the
xylem and thus pull the water UP the xylem =
capillary action!!!
HOW DOES THE XYLEM WORK?
Capillary action & osmosis are not enough to bring the
water ALL THE WAY UP to the leaves.
Transpiration is the
evaporation of water from
the leaves of plants


Transpiration is like you
sucking on a straw!
The water exits the leaves
through openings, or
pores, called stomata
H2O
H2O
STOMATA
 stomata not only allow water vapor to evaporate from
the leaves of plants
What else could enter and exit through these
very tiny openings?
 Stomata also allow gases into and out of the plant
What gas is entering the plant?
What gas is exiting the plant?
O2
CO2
NOW WE KNOW HOW PLANTS
TRANSPORT WATER UP, BUT WHAT
HAPPENS WHEN IT REACHES THE
TOP?!?
WATER LOSS



On average, plants use 90% of water that enters
the through their roots
What doesn’t get used, is lost through
transpiration – when the water evaporates from
the leaves through the stomata
This helps cool the leaf, which is great, but it also
means water is lost, especially when it is very hot
or dry – conditions when the plant should be
“saving” water!!!
TRANSPIRATION RATES
 Vary from plant to plant.



Broad leaves= ___________
higher transpiration rates
Narrow leaves= __________
lower transpiration rates
Depends upon environmental factors



Temperature
Humidity
Air Movement

In what type of environment
would transpiration rates be
highest?
.
TO PREVENT WATER LOSS, PLANTS
HAVE HAD TO ADAPT!
1. Thin, narrow leaves
Why? Decreased surface area
2. Reduced number of stomata
Why? Fewer places from which water can escape
3. Guard cells
What?!? Two specialized cells that surround
each stoma and control how “open”
or “closed” they are
TO PREVENT WATER LOSS, PLANTS
HAVE HAD TO ADAPT!
4. Cuticle
What?!? Thick, waxy layer on the outside of
plants that helps seal in water
5. Water Storage
Why? The large, central vacuoles of each cell
store extra water for dry times!
ON THE LEFT OR RIGHT SIDE OF YOUR
NOTEBOOK, COMPLETE THE FOLLOWING
REFLECTION:
Trace the pathway of water from the roots and shoots
systems of a plant to the atmosphere.

Use the following terms:






Cohesion
Adhesion
Capillary Action
Transpiration
Evaporation
Include data from your lab activities and demos to support
your explanations.
* This should be well written, in complete sentences!