Plants
Structure and Function
Adaptations
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!
Nonvascular vs. Vascular
Nonvascular plants do not have a system for transporting
water and other nutrients within their body
– Nonvascular plants are small and lack vascular tissue (roots, stems and
leaves).
– Mosses, liverworts, and hornworts are nonvascular plants.
Nonvascular vs. Vascular
Vascular plants are plants that contain structures with vascular tissue
(roots, stems and leaves)
– Seedless plants
– Seed plants
• Gymnosperms and Angiosperms
• Vascular 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
Vascular Plants
Seedless Vascular Plants:
– Seedless vascular plants produce
spores with thickened walls that
prevent them from drying out.
– Examples: Ferns, club mosses,
horsetails, and whisk ferns are
seedless vascular plants.
Reproduce with spores
- diagram shows spores growing in
clusters called sori on the back of
the fern
http://en.wikipedia.org/wiki/Image:Lycopodium_plant.jpg
Structures of Vascular Plants
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
Vascular Plants
• Vascular Plants that produce seeds:
– Gymnosperms
• Produce cones
– Conifers, cycads, ginkgoes, and gnetophytes
– Angiosperms
• Fruits or flowers
– The angiosperms are classified as either monocots or dicots.
Angiosperms
Monocot vs. Dicot
• 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),
Tissues, Roots, Leaves, Stems
Tissue
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.
– 3.Vascular Tissues Vascular tissue conducts water,
minerals, and organic compounds throughout the plant.
• Xylem (carries reactants) vs. phloem (carries products)
Vascular – refers to an internal
system of tubes or vessels to
transport materials
throughout the plant
- 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
Translocation Organic compounds
are pushed through the phloem
from a source to a sink in a
process called translocation.
Transpiration Transpiration, the
loss of water from a plant’s
leaves, creates a pull that draws
water up through xylem from
roots to leaves.
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)
Stems
Function: support and transfer
• Contain the Xylem and Phloem
• Help define plant types (shrubs, vines, trees,
etc)
Simple leaf shapes
Leaves
• Site of photosynthesis
• composed of blade, veins, petiole
• simple or compound
Compound leaf shapes
Entire leaf
Singly compound leaf
Palmate (heart shaped)
Palmately compound leaf
Palmately lobed
Pinnately lobed
Doubly compound leaf
• There are different layers of leaves
• epidermis – adaptation for terrestrial life- covering
of leaf
• waxy cuticle - coats upper and lower epidermis
• stomata – site of transpiration
• Guard cells- control water loss by closing a plant’s
stomata when water is scarce
See pg. 559 – Yes, you need
to know the layers of leaves
Plant Adaptations
• 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.
Vascular Plant Adaptations
• 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.
Plants in our Lives
• 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.
• 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.
Plants in Our Lives
• 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.
Fruit or Veggie?
• A fruit is the ripened ovary and contains
seeds.
• Therefore, tomatoes, peppers, squash,
olives, and cucumbers are FRUITS, not
vegetables.
Vascular Plants (Tracheophytes)
Nonvascular Plants
(Bryophytes)
- spores
Seed Plants
Seedless Plants
- spores
Mosses
Liverworts
Hornworts
26,000 species
Ferns
12,000 species
Conifers
(Gymnosperm)
600 species
Flowering Plants
(Angiosperm)
260,000 species
Monocot
60,000 species
Most grains
Dicot
200,000 species
Most flowering plants