Transcript flowerstructure

Plants: Grouped by characteristics

Vascular

Three main parts: roots, stems and leaves
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Roots can be different sizes:
 Fibrous and tap roots
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Storage roots; beets, carrots, sweet potatoes and
turnips
 Roots have different functions: anchoring the plant,
taking in water and minerals, and store food.
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Nonvascular
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Simple; most grow in moist places
No vascular tissues.
Vascular Plants: Stems
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Function of stems

Support, transport of water & food
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Types of stems
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Most stems grow upward
Some stems grow sideward
Green
Woody
Transport of materials

Xylem & phloem
Vascular Plants: Leaves
Leaves come in variety of shapes and
sizes
 Leaves are arranged in different ways

Plants reproduce
differently
Reproduce – it
means “to make
more of the same
kind”
Plants are classified by characteristics.
Plants that make seeds
Flowering
Plants
Conifers
Plants that do not make
seeds
Ferns
Mosses
a
protective
covering
that
surrounds
the seed
anchor the
plant in place
and absorb
water and
other
minerals
from the soil.
makes seeds.
makes the
plant's food.
carries water and
food to the rest of
the plant.
Basic Plant Structure
Some flowering plants are
monocot
seed – a
seed that
has one
seed leaf
and stored
food
outside the
seed leaf
dicot seed – a
seed that has
two seed leaves
that contain
stored food
Parts of a seed

Dicot
Seed coat
Hypocot
yl
Epicotyl

Monocot
Endosperm
Cotyledon
s
Seed
coat
Epicotyl
Hypocotyl
Cotyledo
n
Radicle
Seed Germination
Monocot
Dicot
Epigeous
Hypogeous
Radicle
Leaf Morphology
Leaf Morphology
Structure: Leaf Types
Structure: Leaf Venation
Structure: Leaf Arrangement
Woody Plant Stem
Stern 2006
Woody Stem Structure
What are the critical parts of a tree?
Bark
Cambium/Phloem
Xylem (earlywood/latewood)
Wood Plant Stem
Stern 2006
ANGIOSPERMS
The flowering
plants
Spring crocus Crocus vernus
Flower structure
Flowers are reproductive structures
 The have evolved to send and receive
pollen from one flower to another
 This is process of pollination
 Flowers are developed from a series of
modified leaves
 These leaves are arranged in a rings
(whorls)

Flower structure
Dog rose Rosa canina
Structure of flowers
Flowers are composed
of four whorls. From
the outside in, they
are:
•
Calyx (sepals)
•
Corolla (petals)
•
Androecium
(stamens)
•
Gynoecium
(pistils)
Flower Morphology
Flower structure
Stigma
Style
Ovary
Petal
Anther
Sepal
Filament
Calyx (sepals)
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Outermost whorl
Usually green
Protects developing
flower

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Physically
Chemically
Made up of SEPALS
Sepals free or not
Calyx radially or
bilaterally symmetric
Corolla (petals)
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Is usually colorful
and showy;
Attracts pollinators
Guides pollinators;
Is composed of
petals
Petals may be united
or separate;
Corolla may be
radially or bilaterally
symmetric.
Androecium (stamens)
Is composed of
stamens
 Stamens have
filaments and
anthers
 Pollen is produced
in anthers
 Stamens can be
free or united
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Gynoecium (pistils)
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Is composed of
pistils
A pistil is composed
of an ovary, style,
and stigma.
Styles may be
separate, branched,
or united
Pistils have a slide of
their own – just wait
Structure: Flowers- missing parts
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Floral Parts Structure
Reproduction
Sepals, Petals,
Complete
Perfect
Stamens, Pistil
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Sepals, Stamens, Incomplete
Perfect
Pistil
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Sepals, Stamens
Imperfect
Incomplete
Structure- Compound Flower/
Sunflower
Structure- FlowerCompound Pistil/ Strawberry
Structure: Flower Parts
How Do Flowers Make Seeds
and Fruits?
Ovary – the
bottom part of
the pistil in
which seeds
form
Ovule - the inner
part of an ovary
that contains an
egg
embryo – tiny
part of a seed
that can grow
into a new plant
How Seeds Form
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After fertilization the flower
dries up and petals fall off,
leaving just the pistil and its
ovary.
The top of the pistil falls off and the ovary gets
larger as one or more seeds form inside it.
When the seeds are formed, the ovary dries up
and the seeds fall out.
Corn, Beans, and Peas are seeds that we eat
How Fertilization Occurs

When a pollen grain reaches a pistil, it
grows a thin tube to the ovary. Sperm
from the pollen grain combines with an
egg, and a seed forms.
Fertilization –
the combination
of sperm from a
pollen grain
with an egg to
form a seed
How Pollination Occurs

Pollination- the
movement of
pollen from a
stamen to a pistil
Butterflies may carry pollen
from the stamen of one
flower to the pistil of the the
same flower. Sometimes
the butterfly may carry
pollen from the stamen of
one flower to the pistil of
another flower of the same
kind.
Types of pollination

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Wind
Animal
Water
Bumble bee Bombus hortorum on red clover Trifolium pratense
Yorkshire fog grass Holcus lanatus
Animal pollination
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Usually insects
Also other flying
animals
e.g. hummingbirds or
fruit bats
Cerambycid beetle
pollinating bramble
Rubus fruticosus
Pollination
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Pollen grains contain the
male gametes of the plant
They are picked up by a
pollinator and transferred
to another flower
Plants tend to specialise in
pollinators
This ensures the pollen is
delivered to same species
of plant
Yellow archangel Lamiastrum
galobdolon being pollinated by
a bumble bee Bombus
hortorum
Pollination
Small skipper Thymelicus flavus on marsh thistle Cirsium palustris
Pollination
The honey bee Apis melifera on marsh thistle Cirsium palustris
Pollination

Some flowers are
highly specialised to
encourage only one
type of insect
Fox glove flowers
Digitalis purpurea
Pollination
Most species of flowering plants are
hermaphroditic
 Pollen from a flower could land on the
stigma of the same flower or another
flower on the same plant = self
pollination
 Pollen transferred from the anther on one
flower to the stigma of another flower on
a different plant = cross pollination

Fertilisation
Pollination ≠ Fertilisation
 The male gamete (the male nucleus) has
to get to the egg cell
 The egg cell lies in an ovule in an ovary at
the centre of the plant
 The pollen grain germinates on the stigma
 It grows a pollen tube down the style
 It male nuclei travel down the pollen tube
to the ovule
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Fertilisation
Pollen grain
Stigma
Style
Ovule
Embryo sac
Ovary
Pollen tube
Fertilisation
Embryo sac
Polar nuclei
Egg cell
Micropyle
Fertilisation
Pollen grains of the daisy
Bellis perennis
Fertilisation
Germinating pollen grains of blue
bell, Hyacinthoides non-scripta
The double fertilisation
Ovule
Nucellus
Pollen
tube
Male nucleus
+ 2 polar
nuclei =
endosperm
nucleus (3n)
Male nucleus
+ egg cell
= zygote (2n)
Pollen tube
entering
micropyle
From flower to fruit
Marsh marigold Caltha palustris
Fruits and seed dispersal
Animal dispersal Strawberry Fragaria vesca
Explosive dispersal
Bird’s foot trefoil
Lotus corniculatus
Wind dispersal
Ragwort Senecio
Animal dispersal
Wood avens
Geum urbanum