Chapter 23
Introduction to Plants
Section 1: Adaptations of Plants
Section 2: Kinds of Plants
Section 3: Plants in Our Lives
Plant Structure & function
The Plant Cell- review
• Are plants autotrophic or heterotrophic?
– Autotrophic (remember, plants are producers and they
make their own food via photosynthesis)
• Are plants prokaryotic or eukaryotic?
– Eukaryotic (remember, eukaryotes have nuclei just like
we do and YOU are EUkaryotes)
• Are plants multicellular or unicellular?
– Multicellular!
• Plant cell walls are made of….
– Cellulose
The Plant Cell:
Label!
Vocabulary:
Vascular – refers to an internal system of tubes or
vessels to transport materials throughout the plant
*basis or first major division of plants into
bryophytes (vascular) and tracheophytes
(nonvascular); includes:
- xylem – transports water and minerals up from
the roots to the shoots
- phloem – transports sugar (food) down from
the leaves to the rest of the plant
• Xylem
brings
water up
from the
roots to
the
shoots
Phloem carries
sugar (food)
down from
leaves
throughout the
plant
Section 1
Adaptations of Plants
Establishment of Plants on Land
• Absorbing Nutrients
• To survive on land, plants evolved
the ability to absorb mineral nutrients
from the soil.
• Preventing Water Loss
• To survive on land, plants evolved a
waxy outer covering called a cuticle,
and stomata and guard cells for gas
exchange, to prevent their bodies
from drying out.
• Reproducing on Land
• To survive on land, plants use pollen
to reproduce without water and
transmit male gametes.
http://en.wikipedia.org/wiki/Image:Devils_Punchbowl_Waterfall%2C_New_Zealand.jpg
Section 1
Adaptations of Plants
Vascular Tissue, Seeds, and Flowers
• Advantages of Conducting Tissue
• Vascular plants have a system of
well-developed tissues that transport
water within a plant.
• Advantages of Seeds
• Seeds protect and nourish a plant’s
embryo, disperse the offspring, and
delay the growth of the embryo until
conditions are favorable.
• Advantages of Flowers
• Flowers make reproduction more
efficient by promoting pollination.
http://upload.wikimedia.org/wikipedia/commons/4/46/Diversity_of_plants_image_version_3.png
Section 1
Adaptations of Plants
Plant Life Cycles
• The Vascular-Plant Sporophyte
– The sporophytes of vascular plants have a vascular
system. Their bodies consist of an aboveground shoot
and an underground root.
More Vocabulary
Seed- adaptation to terrestrial life composed of a plant
embryo, stores food and contains a protective coat
Cone- reproductive structure of gymnosperms; contains
pollen in males and ovules in females
Ovulate cone- from a pinetree (female)
Staminate cone- from a pinetree (male)
Flower- reproductive structure of angisperms composed
of 4 sets of modified leaves
Fruit- mature ovary of a flower that protects dormant
seeds and aids in their dispersal
Cotyledons – nonphotosynthetic leaves of
an immature plant; provide source of
nutrients until plant can produce its own
food
Kinds of Plants
Nonvascular vs. Vascular
• Nonvascular plants do not have a system for
transporting water and other nutrients within their
body
• Vascular plants are plants that contain structures with
vascular tissue (roots, stems and leaves)
– Seedless plants
– Seed plants
• Gymnosperms and Angiosperms
Section 2
Kinds of Plants
Nonvascular Plants
• Key Features of Nonvascular Plants
– Nonvascular plants are small and lack vascular tissue (roots,
stems and leaves).
• Kinds of Nonvascular Plants.
– Mosses, liverworts, and hornworts are nonvascular plants.
http://en.wikipedia.org/wiki/Image:Anthoceros_levis.jpg
Bryophytes – nonvascular plants
20 mm
Liverworts
Hornwort
Moss
Bryophytes – nonvascular plants
- economically important
Ex) sphagnum moss – also called peat or peat moss
Grows in boggy areas called peat bogs; extremely
absorbant; used in agriculture/horticulture
Section 2
Kinds of Plants
Seedless Vascular Plants
• Key Features of Seedless
Vascular Plants
– Seedless vascular plants produce
spores with thickened walls that
prevent them from drying out.
• Kinds of Seedless Vascular
Plants
– Ferns, club mosses, horsetails,
and whisk ferns are seedless
vascular plants.
Tracheophytes – vascular plants
• Seedless plants –whiskferns, horsetails,
and ferns
Whisk fern
horsetail
fern
Seedless vascular plants – ferns
- reproduce with spores
- diagram shows spores growing in clusters
called sori on the back of the fern
Seedless vascular plants dominated during
the Carboniferous period.
Section 2
Kinds of Plants
Gymnosperms
• Key Features of Gymnosperms
– Gymnosperms are seed plants that produce cones.
• Kinds of Gymnosperms
– Conifers, cycads, ginkgoes, and gnetophytes are gymnosperms.
Tracheophytes – vascular plants
• Seed plants
• Gymnosperms – have seeds in cones; include:
ginkgos, cycads, gnetophytes, and conifers
Ginkgo
Cycad
Welwitschia
Gnetum
Ephedra
Gymnosperms called gnetophytes;
only 3 extant species
Conifers: top row: Douglas fir, Sequoia, Cypress;
bottom row: juniper, Australian pine tree; not
shown: yew, spruce, other pines
Section 2
Kinds of Plants
Angiosperms
• Key Features of Angiosperms
– Angiosperms are seed plants that produce flowers and fruits.
• Kinds of Angiosperms
– The angiosperms are classified as either monocots or dicots.
Monocots vs. Dicots
• Monocots:
– One cotyledon
– Veins parallel
– Vascular bundles in
complex arrangement
– Fibrous root system
– Floral parts in
multiples of three
– Ex. Iridaceae (irises),
Liliaceae(lilies) and
Poaceae (grass).
• Dicots:
– Two cotyledon
– Veins netlike
– Vascular bundles
arranged in ring
– Taproot usually
present
– Floral parts in four or
five
– Ex. Asteraceae
(composite),
Brassicaceae (mustard),
Fabaceae (legume), and
Rosaceae (rose),
Subgroups of Angiosperms:
Monocots & Dicots
Tracheophytes – vascular plants
* Seed plants
•Angiosperms – flowering
plants - have flowers, fruits,
and seeds
Grasses are flowering plants, too. So are
trees.
Grass
flowers
Flower
pistil
Section 3
Plants in our Lives
Plants as Food
• Fruits and Vegetables
– All types of plant parts—roots, stems, leaves, flowers, fruits,
and seeds—provide food for humans.
• Root Crops
– Root crops, such as potatoes, grow underground.
• Legumes
– Legumes, such as peas, produce protein-rich seeds in long
pods.
Section 3
Plants in our Lives
Cereals
• Wheat
– For more than one-third of the world’s population, wheat
is the primary source of food.
• Corn
– Corn is the most widely cultivated crop in the United
States.
• Rice
– For more than half of the people in the world, rice is the
main part of every meal.
Fruit or Veggie
Humans eat lots of
different plant
parts. A fruit is the
ripened ovary and
contains seeds.
Therefore,
tomatoes, peppers,
squash, olives, and
cucumbers are
fruits, not
vegetables.
Vegetables – the vegetative parts of the plants that we
eat. Includes:
•
Roots – carrots, turnips,radishes
•
Stems – celery, bok choi, rhubarb, garlic,
broccoli, onions, potatoes
•
Leaves – lettuce, cabbage, parsley
Other plant parts that we eat:
Seeds – pinto beans, peas, sunflower seeds,
corn, pepper corns, rice, pecans, coconut
Flowers – anise flowers (licorice), basil;
http://homecooking.about.com/library/weekly/blflowers.htm
Good rule of thumb: if you didn’t get it at the store, DON’T EAT IT!
Section 3
Plants in our Lives
Nonfood Uses of Plants
• Wood
– Wood is a source of wood pulp used for making
paper, lumber used for building materials, and fuel.
• Medicines
– Many important medicines are currently made from
plants or were originally derived from plants.
• Fibers
– Plant fibers are used to make paper, cloth, and rope.
The most important sources of plant fibers are wood
and cotton.
http://upload.wikimedia.org/wikipedia/commons/0/0b/Taxus_wood.jpg
We don’t just eat plants, we also wear them, build
with them, and use them for medicines!
Plant Structure & Function
Chapter 25
Pg. 551 - 564
More Review
Do you remember the equation for
photosynthesis
6H2O + 6CO2 + sunlight 6O2 + C6H12O6
Do you remember what organelle
photosynthesis takes place in?
The Chloroplast
Plant Structure
• Plants are
composed of:
–
–
–
–
Tissue
Roots
Leaves
Stems
Each plant part – tissue, root,
stem, leaf - has a specific role in
keeping the plant alive through
photosynthesis
Structure:
Tissues- 3 types
Vascular Plant Body
A vascular plant’s body contains three kinds of
tissues—dermal tissue, ground tissue, and vascular
tissue.
– 1.Dermal Tissue Dermal tissue covers a plant. A thin
layer of epidermis covers nonwoody parts. Several
layers of cork cover woody parts.
– 2.Ground Tissue Ground tissue is specialized for
photosynthesis in leaves and for storage and support in
stems and roots.
Review: Vascular Tissues
– 3.Vascular Tissues Vascular tissue conducts
water, minerals, and organic compounds
throughout the plant.
• Xylem - contains vessels, which are made up of
cells that conduct water only after they lose their
cytoplasm. Water flows between cells through pits
and perforations in their cell walls.
– Carry reactants
• Phloem -contains sieve tubes, which are made up of
cells that are still living. Substances pass between
the cells through pores.
– Carry products
Plant Structure:
Roots
• Function- absorption, storage and anchorage
• Roots have a central core of vascular tissue that is
surrounded by ground tissue and epidermal tissue.
• Root hairs on root tips increase the surface area which
increases absorption
• Remember that Nitrogen Fixation happens in the roots!
(Nitrogen fixation is when nitrogen in the
atmosphere is converted by bacteria into
nitrogen compounds like ammonia,
nitrates and
nitrites)
Plant Structure:
Leaves
•
•
•
•
Site of photosynthesis
composed of blade, veins, petiole
There are different layers of leaves (next slide)
simple or compound
Leaves
Cross Section
- epidermis – adaptation for terrestrial life- covering of
leaf
- waxy cuticle - coats upper and lower epidermis
- stomata – site of transpiration
Movement of Water :
• Transpiration Transpiration, the loss of water
from a plant’s leaves, creates a pull that draws
water up through xylem from roots to leaves.
• Guard Cells and Transpiration Guard cells
control water loss by closing a plant’s stomata
when water is scarce. Thus, they also regulate the
rate of transpiration.
Movement of Organic Compounds
• Translocation Organic compounds are pushed
through the phloem from a source to a sink in a
process called translocation.
See pg. 559 – Yes, you
need to know the
layers of leaves
Plant structure:
Stems
• Function: support and transfer
• Contain the Xylem and Phloem
• Help define plant types (shrubs, vines, trees, etc)
Chapter 25
Plant Structure and Function
Leaves lose
water by
transpiration.
Leaves produce
sugars in
photosynthesis.
Sugars are
transported
downward in the
stem.
Sugars are transported
upward to leaf buds in the
spring.
Water enters the xylem of roots and
moves upward into the xylem of the
stem.
Sugars are
transported
downward into roots
for use or storage.
Sugars are
transported
into flowers
and fruits.
Overview of
plants and
photosynthesis
happenings