Transcript 5.2 Intro to plants and vascular tissue - Blyth-Biology11

Intro to Plants
and
The Vascular System
5.2
KINGDOM PLANTAE
• Plants evolved about 500 million years ago from
simple green algae that lived in the ocean.
• All plants are autotrophic and some, like the
famous Venus fly-trap, can also be heterotrophic.
• All plants are eukaryotic and multicellular.
PLANT CELLS
• Like animal cells, plant
cells contain a nucleus
and organelles, but they
have two distinguishing
features:
– Cell wall (made of
cellulose, a complex
carbohydrate, provides
rigid structural support;
difficult to digest)
– Chloroplast (organelle
that conducts
photosynthesis)
Animal cells have lysosomes that release the cellular equivalent of
digestive enzymes. Why don’t plants need these?
PLEASE... CONSIDER THE
FOLLOWING:
• How can plants stand up straight without a
skeleton?
PLANT DIVERSITY
• Currently over 350 000 species of plants,
including:
– Mosses
– Ferns
– Conifers
– Flowering plants
• Most plants live on land and can withstand
a wide variety of climates. Cacti live in arid,
dry areas whereas mosses need to be in
moist environments to survive.
CLASSIFYING PLANTS
• Plants are classified based on the
presence or absence of vascular
tissue
• Vascular tissue can be compared
to arteries and veins: a network of
specialized cells that allows plants
to transport water, minerals and
sugar throughout the plant
• What would you expect a nonvascular plant, without vessels to
transport nutrients and water, to
look like?
Plants
Cannot
transport foot
or water
between plant
parts
Non-vascular
(ex. moss)
Vascular
(ex. tree,
sunflower)
Transport of
fluid is
through
simple
absorption or
osmosis
Contain a
vascular
system
allowing for
transportation
of nutrients /
water
throughout
the plant
Must live in
moist
environments;
need water
for
reproduction
WHAT MIGHT VASCULAR
PLANTS LOOK LIKE?
FUNCTION
OF
STEMS
1.Support system for plant body
2.Transport system carries water & nutrients
(through vascular tissue!)
3.Holds leaves & branches upright
Looking at the
picture below:
What years had
the most rain?
What years
experienced the
worst drought?
FUNCTION OF LEAVES
1. Main photosynthetic organ
2. Broad, flat surface increases surface
area for light absorption
3. Have systems to prevent water loss
• Stomata open in day but close at
night or when hot to conserve
water
• Waxy cuticle on surface
4. System of gas exchange
• Allow CO2 in and O2 out of leaf
Elephant Ear Plant
Leaf Cross-Section
LEAF
STRUCTURES
waxy layer;
2. Veins: transports water,
nutrients and food
– Made of xylem and
phloem vascular
tissue
Mesophyll
1. Cuticle:
covers upper surface
– Protects leaf against
water loss
3. Mesophyll: Spongy and
Palisade
- contains cells that
perform photosynthesis
b/c they contain
chloroplasts.
Cuticle
Veins
Stoma
(Opening)
2 Guard
Cells
Surround
each
Stoma
LEAF STRUCTURES
4. Guard cells:
• Cells that open and close the stoma
• Conserve water by preventing excess water
transpiration
5. Stomata: openings in leaf’s surface; when open:
• GAS EXCHANGE: Allows CO2 in & O2 out of leaf
• TRANSPIRATION: Allows excess H2O out of leaf
Guard Cells
Stoma
1.
2.
3.
FUNCTION
OF
Anchor
& support plant
in the ground
Absorb water &
minerals
Hold soil in place
Root Hairs
ROOTS
Fibrous Roots
Root
Hairs
STRUCTURE
OF ROOTS
1.Root Hairs:
increase surface
area for water &
mineral
absorption
2.Meristem:
region where
new cells are
produced
Meristem
Root
Cap
3.Root Cap:
protects tip of
growing root
Where do you think all new growth starts?
Types of Roots
A: Fibrous root
B: Taproot C: Modified root
QUIZ TIME! BEFORE WE CONTINUE…
VASCULAR OR NON-VASCULAR?
“Naked seeds” are not
enclosed in an ovule (like a
pine cone).
Gymnosperms
Plants are usually evergreens.
Ex. pines, cedars, spruces and
firs.
VASCULAR PLANTS
Mature seed is surrounded by
the ovule (think of an apple).
Contain a vascular system
allowing for transportation
of nutrients / water
throughout the plant
Angiosperms
Angiosperms are trees/plants
that shed leaves every
autumn.
Ex. Oaks, maples and
dogwoods are examples of
deciduous trees.
http://dendro.cnre.vt.edu/forsite/idtype.htm
QUIZ TIME! BEFORE WE CONTINUE…
GYMNOSPERM OR ANGIOSPERM ?
KEY WORDS: PLANT
BIOLOGY
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Cell wall
Chloroplast
Vascular tissue
Non-vascular tissue
Stomata
Cuticle
Veins
Mesophyll
Chlorplast
Guard cell
Stomata
Transpiration
Root hair
Meristem
Root cap
Gymnosperm
Learning Check
• Pg 557, Q 19-24
Vascular Systems
Vascular Systems
• Like humans, plants
have a vascular
system for moving
water and nutrients
around.
• Unlike humans
though, they do not
have a pumping
mechanism.
Monocot and Dicot Vascular Tissue
Arrangement
• Remember the arrangement of vascular tissue
in dicots and monocots.
Xylem
• Water transport
• Consists of two main cell
types: tracheids and
vessels elements, both
are non-living, hollow
cells.
• Start as living cells, grow
to fill the space required
and then die and become
hollow, easily allowing
water to move through.
• Gymnosperms only have
tracheids as part of their
Xylem.
Phloem
• Sugar movement
• Made up of living cells,
which use oxygen while
moving sugar around,
therefore use energy.
• Made up of sieve tube
elements connected by
sieve plates. Companion
cells lie adjacent to sieve
tubes and help provide
energy.
• Pg 549, Q 7-12