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Plant Cell
Plants are:
Eukaryotic
Autotrophic
Multicellular
Cell walls of cellulose
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 and
tracheophytes; 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
Bryophytes – nonvascular plants
Examples include:
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
Seed dispersal by edible fruit, by wind, as well as other
means. The picture to the right is of a samara from a maple
tree.
Vocabulary
Seed – adaptation to terrestrial life
composed of a plant embryo, stored
food, and a protective coat
Which is a monocot and which is a dicot? How do you know?
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
frond of the fern
Seedless vascular plants dominated during
the Carboniferous period.
Vocabulary
Cone – reproductive structure of
gymnosperms; contains pollen in
males and ovules in females
Flower – reproductive structure of
angiosperms composed of 4 sets of
modified leaves
Fruit – mature ovary of a flower that
protects dormant seeds and aids in
their dispersal
Ovulate cone from a pinetree (female)
Staminate cone from
a pinetree (male)
Tracheophytes – vascular plants cont.
•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
Tracheophytes – vascular plants cont
* Seed plants
•Angiosperms – flowering plants - have
flowers, fruits, and seeds
Grasses are flowering plants, too.
So are trees.
Grass
flowers
Flower
(male)
pistil
(female)
Ovaries with ovules become fruits
with seeds after the ovule (egg) is
fertilized by sperm from the pollen
Pollen grains contain sperm.
They are produced in the anthers
of the flowers in angiosperms.
Pollination
- by many vectors, including:
Wind
Water
Animals
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!
We don’t just eat plants, we also wear them, build
with them, and use them for medicines!
Plant Structure & Function
Each plant part - root, stem, leaf - has a
specific role in keeping the plant alive through
photosynthesis
Monocots & Dicots
Cotyledons – nonphotosynthetic leaves of
an immature plant; provide source of
nutrients until plant can produce its own
food
Leaves
- site of photosynthesis
- cross section
- epidermis – adaptation for terrestrial life
- waxy cuticle
- stomata - transpiration
Leaf
Leaf structure supports its function as
the primary organ for photosynthesis
Leaves
- composed of blade, veins, petiole
- simple or compound (see identifying leaves ppt)
- pinnately or palmately compound
- alternate or opposite if compound
- pinnate or palmate venation
Overview of movement of photosynthesis
reactants and products through a plant
Stems
Support and transport
Contains xylem and phloem
Modified:
Strawberry runners
potatoes
onion
Stems
Define plant type: herbaceous, shrub,
vine, tree
Herbaceous plant
shrub
vine
Stems – cross sections through a dicot
and a monocot
Roots
Function – absorption, storage,
anchorage
Root hairs –
extensions of the epidermis that
increase absorption by increasing surface area; see
photo
Fibrous roots – see monocot information
Tap roots – see dicot information
Root Structure
Nitrogen fixation – occurs in the roots and
in the soil around the roots of plants;
performed by bacteria
Plants that live in nitrogen poor soils trap
and break down insects with enzymes to
obtain nitrogen
Venus fly trap
Pitcher plant
Vocabulary
Primary growth – increase in length;
stems get longer, roots grow deeper
Meristem – tissue that is growing
Apical meristem – tissue found at the
tips of roots and stems that is actively
dividing/growing
Plant Responses
Plant responses are called tropisms.
Tropisms can be positive or negative. They
include phototropism, gravitropism, and
thigmotropism.
Most plant responses involve the action of
hormones, including gibberellins, auxins, and
ethylene.
Plant Responses
Effect of
gibberellens on
Thompson’s
seedless grapes
and on growth in
a dwarf plant
Auxins make
plants bushier by
making more
branches at
nodes when the
apical meristem
is cut off (the
tips of the
existing
branches)
Positive Phototropism
Effect of ethylene
on the ripening of
an apple.
NEGATIVE Gravitropism in Stems
http://plantsinmotion.bio.indiana.edu/plantmotion/movements/tropism/gra
vitropism/gravi1/gravitrop.html
Vines Illustrate Positive
Thigmotropism