Transcript Structure and Funciton of Plant Organs

PLANT
ORGANS
Plants generally have four organs:
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Roots
Stems
Leaves
Flowers
ROOTS

Roots hold the plant in place and they absorb
water and minerals. Roots usually grow in the
direction of gravity (down) which is why they are
most often found underground. They have no
leaves. In short, the roots are in the ground and
they give the plant water to help make its food.
All roots have a tip.
 The growing tip of roots is protected by a
root cap consisting of concentric layers of
cells surrounding the apical meristem where
new root cells are produced.

Root Hairs

Minerals and water molecules enter root hairs
and travel through the cells of the cortex by
osmosis.
Label the Picture: Root hairs and
root cap
Apical meristem: the zone of dividing
cells at the root apex which give rise to
new cells in a growing root.
 Elongation
also occurs within the
roots.
 What is elongation?
• Label the picture with the
following words: elongation and
apical meristem.
STEM
Stems are generally above ground, grow
upward, and have leaves.
 Can stems be different from one another?

Stems of cactus: Give two more
examples of stems
Phloem
Some plants have bark which
contains phloem.
 It is a tissue that conducts
synthesized food (glucose)
substances (e.g., from leaves) to
parts where needed by
transporting the food made in
the leaves, down the stems and
into the roots. Phloem-FLOWS
down the plant!
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Xylem

acts as a protective layer on the outside of
the plant which helps prevent damage and
water loss. It absorbs water and minerals
through the roots and transports them up
the stem and into the leaves. Xylem
transports UP the plant.
Phloem does what?
Xylem does what?
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Phloem brings food down the plant.
Xylem brings water and minerals up the plant.
Xylem and phloem can be
referred to what organ
structures within the human
body?
Why would they call the xylem
and phloem vascular tissue?
 Phloem
and Xylem inside of a stem
are found inside vascular bundles.
 Inside an individual root their inside an
endodermis.
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The table below will help you remember the differences between
the two types of vessel:
Xylem
made of dead cells
cell wall thickness thick
cell wall material lignin
permeability of cell wall impermeable
cytoplasm? none
function transport of water and minerals
carried to ... leaves
direction of flow upward
tissue also has.. fibres
Phloem
living cells
thin
cellulose
permeable
cells lined with
cytoplasm strands
transport of food
growing parts and
storage organs
up and down
companion cells
Vascular Cambium
 one-cell-thick
layer of tissue between
xylem and phloem in most vascular
plants (plants that contain vessels for
transporting) that is responsible for
secondary growth.
 Produces additional vascular tissues!
Vascular vs. Non-Vascular
Vascular: tube-like (water, food, etc.)
Ex. Pine, maple, ferns, grass, ivy sunflowers
Non-vascular: No tubes (osmosis, diffusion)
Ex. Mosses 575
Liverworts
577
Cork Cambium

Located outside the phloem, produces
CORK. Cork cells replace the epidermis
in woody stems and roots, protecting the
plant. Cork cells are DEAD CELLS that
provide protection and prevent water loss.
How Old is that tree?

Each year a tree adds a layer of wood to its
trunk and branches thus creating the
annual rings we see when viewing a
section. New wood grows from the
cambium layer between the old wood and
the bark. In the spring, when moisture is
plentiful, the tree devotes its energy to
producing new growth cells.
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These first new cells are large, but as the
summer progresses their size decreases until,
in the fall, growth stops and cells die, with
no new growth appearing until the next
spring. The contrast between these smaller
old cells and next year’s larger new cells is
enough to establish a ring, thus making
counting possible.
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Wide rings of certain species of trees were
produced during wet years and inversely,
narrow rings during dry seasons.
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Between you and your lab partner grab a
piece of wood and determine the following
pieces of data:
1. How old is your tree?
2. How many dry seasons were there?
3. How many wet seasons were there?
The massive trunk of this Chilean
wine palm has grown in girth due to
the production of new vascular
bundles from the primary and
secondary thickening meristems.
LEAFS
The leaf contains veins and stomatas
• Veins: carry nutrients and water through the
leaf
• Stomatas: are pores in the epidermis of a
leaf or stem through which gases and water
vapor pass.
• Draw a picture of a stomata including their
guard cells. Page. 639
Flowers

Are responsible for one important function
reproduction. Flowers are the plant’s
reproductive structures. Angiosperms are types
of plants that bear fruits and flowers. Flowers
are usually both male and female, and are
brightly colored to attract insects to help them
carry pollen used for sexual reproduction.

Not all flowers are colorful, though. These
flowers usually use the wind for pollination.
Complete Flower
In order to be a complete flower you
must have all four of the following organs:
sepal, petal, stamen, and pistil.
 An incomplete flower is missing one or
more of the flower organs.
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Box Elder Flower!
Flower Anatomy
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The peduncle is the tip of the stalk where the
flower begins.
The receptacle starts at the peduncle and acts as a
base to which all other parts of the flower are
attached.
Sepals are leaf-like protective coverings of the
bud that grow typically in an outer whorl.
Petals are the inner whorl of leaves

Pistils are the female organs. There can be one or
more. There are 3 parts of the pistil:
the stigma receives the pollen and is sticky
 the style connects the stigma to the ovary
 the ovary is where seeds develop
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Stamen are the male organs. The number of
stamen per flower varies. There are 2 parts of the
stamen:
the filament produces pollen
 the anther caps the filament
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Decide what flowers are from the
following choices:
 perfect
 regular
 irregular
 incomplete
 complete
Investigation of the Leaf Stomata
1.
2.
3.
In partners you will be investigating leaf
stomata's on plants.
They are located on the tops and bottoms of
leaves.
Each group will need to make an impression
on both the top and bottom layers of the leaf.
DO NOT TEAR THE LEAF OFF THE
PLANT! Be careful!
4.
5.
Do not begin the lab until you have read
through the lab completely. Then you may
begin.
Make sure you obtain the proper materials and
return them once you have used them.
 Will
plants have more stoma open
during the day than during the night?
 Make a hypothesis about the number
of open stomata found in a plant kept
in the dark compared to a plant in the
light.
1st hour-in Light
Stomatas
found on the
top
7, 5, 100ish,
31, 16, 11, 0,
10, 21, 1, 11,
Stomatas
found on
the bottom
7, 100ish,
36, 5, 10
5th hour-in dark
Stomatas
found on the
top
0, 0, 30, 6, 8,
4, 80, 6
Stomatas
found on the
bottom
79, 30, 8, 9,
45ish, 25, 4,
0
Label the Leaf Diagram
Plant Tissue Systems
3.
There are three main types of plant
tissues:
dermal
vascular
ground.
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The tissues help the plant grow
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1.
2.
DERMAL
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The dermal system has the epidermis
which is the outermost layer of the plant
body. It makes the skin of the plant.
Epidermal cells vary in function and
structure.
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The epidermis has
openings through
which gasses are
switched with the
atmosphere. The
openings are enclosed
by guard cells which
change the size of the
stomata openings and
control the gas
exchange.
It is through the stomata's that gas
exchange takes place: photosynthesis
and respiration
 The
epidermis is covered with a
coating called the cuticle, which
serves as a waterproof layer and
reduces water lost through
evaporation.
 What are examples of plants with a
thick cuticle?
Vascular System
 This
system is made up of two types
of conducting tissues. They are the
xylem, which conducts the water, and
dissolved mineral nutrients; and the
phloem, which conducts food.
Ground System
 The
ground tissues of plants
are made up of three tissues.
Roots
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Three main types of roots:
1. Taproot: the first root to
develop from a germinating
seed, also called primary
root, which digs deep into
the soil searching for water.
Taproots can also act as
storage roots, storing water
and minerals for the plant to
survive off of.
Fibrous Root
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Slender, branched roots that look like fine
string of yarn.
Adventitious roots
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Roots that grow from the stems or leaves
of a plant
Contractile roots
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Roots that can change in length and
thickness, pulling shoots closer to the
ground or deeper into the soil.
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The roots grow
downward, then contract,
pulling the plant's crown
(a thick underground
stem called a "rhizome")
deeper into the mud.
Each year, the plant digs
itself deeper into the
earth and extends its
anchor-roots farther
down.
Root Hairs
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Can be found on any root system. They
are tiny projections from the surface cells
of a root that extend through the soil
around the root.
Draw this picture on the bottom of
page 11. Label it Roots.
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This is a picture looking
closely at a root.
Every root has a
protective root cap on
the end. This allows
the new dividing cells a
source of protection
when the root is
digging deep into the
soil.
Draw the following picture (pg. 11)
Vegetable Lab
1.
2.
3.
Between you and your lab partner pick 3
vegetables to observe and dissect
Fill our the data table regarding your
vegetables.
Next, dissect only a small portion of the
vegetable. Then place your vegetable
back for other classes to use.
4.
5.
Look at a section of your plant under
the microscope and draw a picture of
what you see.
Answer the questions
MONOCOTS & DICOTS (pg. 8)
 Traditionally,
the vast world of
flowering plants, phylum
Anthophyta, has been known as the
angiosperms. It has been divided into
two great subdivisions, or classes,
known as the monocots and the dicots.
Monocots vs. Dicots
Answer these questions on page 11 in
your lab book.
Read the inside story on page 628 and
answer the following questions:
1. What are meristems?
2. What are the different types of
meristems?
1.
What are meristems?
Produce new plant cells.
2.
Types of meristems?
1) apical meristem: height
2) vascular cambium: width in stem
3) cork cambium: Bark