Transcript Plant Cells & Tissues - Ashley Schevers' Biology I Website

Take 5: 2/16/11
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What is the underground stem that anchors a
fern called? _______________________
Rhizome
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_____________
are the leaves of a fern.
Fronds
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What is something unusual about Ginkophyta?
Female seeds have a bad smell
One known species
Take 5: 3/5/12
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The two structures in which plants reproduce
is ____________
and ____________.
Seeds
Spores
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The female reproductive structure of
nonvascular plants is called a(n) _____.
Archegonia
Liverworts, hornworts, mosses, and ferns are
all examples of __________________.
Non-Seed Plants
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Plant Cells &
Tissues
Ch 23.1
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There are 3 types of plant cells
Parenchyma
 Collenchyma
 Sclerenchyma
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3 types of plant cells
Parenchyma
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most abundant
TWO MAJOR FUNCTIONS = STORAGE
and FOOD PRODUCTION (Photosynthesis)
Also FUNCTIONS TO PRODUCE SAP.
large vacuole stores water, starch grains, oils
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Example: The cells of the white potato.
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Parenchyma
3 types of plant cells
Collenchyma
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unevenly thickened cell walls to
allow cells to grow
FUNCTION = PROVIDE
STRENGTH AND SUPPORT
arranged in tube-like strands
Example: the resilient strands
in stalks of celery
3 types of plant cells
Sclerenchyma
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thick and rigid cells
at maturity, cells die
thick cell wall remains and PROVIDES
SUPPORT
2 cell types: fibers & sclerids
a) fibers = long thin strandlike cells
b) sclereids = irregularly shaped, in
clusters (ex: apple core, gritty pear
texture)
Sclerenchyma
3 types of plant cells
4 types of plant tissue
Dermal Tissue
 Ground Tissue
 Vascular Tissue
 Meristematic Tissue
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Dermal tissues
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FUNCTION = COVER & PROTECT BODY OF
PLANT
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aka epidermis (tightly packed flattened
cells that cover all parts of plant)
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epidermal cells produce waxy _________
to prevent water loss
Dermal tissues
Dermal tissues
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Also has ________ (stomata = plural) to
control water loss.
Stomata are openings in leaf tissue that
control gas exchange.
____________ control opening and
closing of stomata.
Guard cells regulate water loss from leaf.
Dermal tissues
Dermal tissues
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In addition, the
dermal tissue of
roots have
__________
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The function of
root hairs is to
absorb water and
dissolved minerals.
Dermal tissues
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Trichomes = hairlike
projections on stem (“fuzzy
appearance”)
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They function to reduce H20
evaporation from plant
They can also secrete
_________ substances to
protect plant from predators
trichomes
Ground tissue
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FUNCTION = ASSIST WITH
PHOTOSYNTHESIS, STORAGE, &
SUPPORT
Composed mostly of parenchyma
cells
Located throughout plant
Have chloroplasts
Ground tissue in stems and roots
have _______________ for storing
starch grain and water
Vascular tissue
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FUNCTION =
TRANSPORT FOOD,
DISSOLVED
MINERALS, AND
WATER
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Two types of
vascular tissue:
xylem & phloem
Vascular tissue
Xylem
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FUNCTION = TRANSPORTS WATER AND DISSOLVED
MINERALS FROM ROOTS TO REST OF PLANT
tubular shaped cells
made of 4 types of cells:
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a) tracheids
b) vessel elements
c) fibers
d) parenchyma
Vascular tissue
Phloem
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FUNCTION = TRANSPORTS SUGAR AND ORGANIC
COMPOUNDS FROM LEAVES TO REST OF PLANT
tubular cells joined end to end
made up of 2 types of cells
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sieve tube members (have cytoplasm, no nucleus or
ribosomes)
companion cell (have a nucleus, help transport sugars
thru sieve tubes)
large pores at sieve plates exist to allow sugar to
move between sieve tube members
Vascular
tissue
Vascular tissue
Meristematic tissue
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________________ =
region of actively dividing
cells where growing plant
produces new cells
2 typical types
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Apical meristem: near tip
of roots or stems
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produce cells that allow roots
and stems in become longer
Lateral meristem: results in
diameter increase of roots
and stems
Meristematic tissue
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Lateral meristem: results in diameter increase of
roots and stems
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Example: most woody plants
2 types of lateral meristem = vascular cambium and
cork cambium
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vascular cambium = produces new xylem and
phloem cells in stems and roots
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cork cambium = produces cells with tough cell
walls along surface of roots and stems (i.e. bark)
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3rd type exists in grasses, corn, & other monocots,
where the part of stem between leaves grows
(these plants don’t have vascular or cork
meristem)
Meristematic tissue
Roots, Stems &
Leaves
Ch 23.2
Roots
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Roots function as an _________ and are
capable of absorbing _________ and
dissolved minerals.
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They also have _________________ for
transporting water & nutrients.
Roots
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They vary in shape: short, long, thick, thin,
massive, threadlike
Ideally roots want a large _____________ for
absorbing water and dissolved minerals.
Roots
Roots
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There are 2 types of root systems (depends on
environment).
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A) taproot = single, thick structures (ex: carrots,
beets)
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B) fibrous roots = many, small branching roots
(ex: grasses, clovers)
taproot
fibrous
root
Root structure
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Let’s look at the layers within a root, starting
out and working our way in.
Xylem &
phloem
INSIDE
OUTSIDE
Root structure
The outermost structure on a root are ____________________
which increase surface area, ultimately allowing more water,
oxygen, & dissolved minerals to be absorbed
Next layer = cortex
The cortex transports water and dissolved minerals into vascular tissue
Mostly parenchyma cells that store food, water
Root structure
Next layer = endodermis
 A layer of waterproof cell walls around vascular
tissue
 This layer controls water flow & dissolved
minerals into roots
Next layer = pericycle
 Produces lateral roots
Root structure
Xylem & phloem = in center of root
 monocot = vascular bundles surround
central core aka pith
 dicot = central star
Root structure
Xylem &
phloem
INSIDE
OUTSIDE
Makes it longer
Protection
epidermis
Root growth
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Region where roots grow in length =
_______________
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As these newly created cells mature, they
differentiate and take on specific functions.
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The tip of root is covered by __________
(protective layer of parenchyma cells).
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Also, vascular cambium in dicots increases the
_________ of roots.
Stem
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Supports leaves and flowers
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Has vascular tissue to transport water,
dissolved minerals, sugars
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Herbaceous or woody
Some stems store food (to survive harsh
weather) ex: corn, tubers, & rhizomes
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Internal structure of
stems
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Vascular tissue appears in 2 arrangements:
scattered (monocot) & circular (dicot)
Woody Stems
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Examples: conifers, perennial dicots (have thick
sturdy stems)
As plants grow up they also g r o w o u t
The added thickness on sides aka “secondary
growth.” It is created by the vascular cambium.
Woody stems have visible annual growth rings
Woody Stems
outermost
Tissue
layers
innermost
Stems transport
materials
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Xylem transports __________ and dissolved minerals
from _________ to _________
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Phloem carries dissolved __________, hormones, viruses
from __________ to ____________
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“sink” = any portion of plant that stores sugars (ex:
parenchyma cells)
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“translocation” = movement of sugars in phloem
Growth in Stem
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The term “primary growth”
refers to a plant increasing in
length along the stem at nodes
where they give rise to branches
and leaves.
Leaves
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Primary function = ____________________
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Leaves want to have a large ________________ to capture
light.
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Leaf blade = flat broad green structure (vary in size and
shape)
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Some leaves join directly to stem
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Some leaves have a stalk that joins leaf blade to stem
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The stalk of a leaf = petiole (has vascular tissue)
Leaf structure
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Outermost layer = Epidermis
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Next = Mesophyll: Photosynthesizing tissue of
leaf
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Palisade mesophyll = photosynthesis occurs here
Spongy mesophyll = has lots of air pockets for
CO2, O2, & water vapor to exit via stomata
Transpiration
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loss of water via stomata = aka transpiration
Think PERSPIRATION…
when you sweat you lose
water through your pores
Leaf modifications
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A) Some plants release irritants when crushed or broken
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B) Another modification = cactus spines which are modified
leaves (to reduce water loss).
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C) Carnivorous plants use their leaves to trap insects.
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D) Some leaves function as water or food storage sites (ex: aloe
vera)
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E) Bulb = shortened stem, flower bud and immature leaves
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ex: onion, tulips, narcissus, lilies