Gymnosperms

•Gymnosperm means naked seed

•Sexual Reproduction

•Vascular

Coniferophyta

• Cone-bearers

• Needle-like, scaly leaves

Angiosperms• Have Seeds in Fruits

• Flowers with ovaries that become fruits

• Vascular

• Sexual Reproduction

• Monocots and Dicots

Monocots and Dicots

Monocot

Dicot

7

Vascular System• Xylem tissue carries water

and minerals upward from the roots

• Phloem tissue carries sugars made by photosynthesis from the leaves to where they will be stored or used

• Sap is the fluid carried inside the xylem or phloem

• 1.Pistil:female reproductive structure

a.Stigma: sticky tip; traps pollen

b.Style: slender tube; transports pollen from stigma to ovary

c.Ovary: contains ovules; ovary develops into fruit

d.Ovule: contains egg cell which develops into a seed when fertilized

FilamentAnther

StigmaStyle

Ovary

Pistil

PetalSepalOvule

Stamen

Structure of a Flower

2.Stamen: male reproductive structure

a.Filament: thin stalk; supports anther

b.Anther: knob-like structure; produces pollen

c.Pollen: contains microscopic cells that become sperm cells

Structure of a Flower

FilamentAnther

StigmaStyle

Ovary

Pistil

PetalSepalOvule

Stamen

Cross Pollination• How does pollination happen?• Pollen from an anther is caught

by the stigma, travels through style to the ovules in the ovary.

• What is the result of pollination?• A Fruit: An ovary containing

seeds.

Seeds and Fruit• Fruits are formed by seed

plants to aid in dispersing seeds

• A seed contains the developing plant embryo in a protective coat (testa)

• Seeds form from ovules fertilized in the ovary

• Ovaries with seeds ripen into dry or fleshy fruits

Parts of a Seed• External seed coat or testa• Developing plant embryo• Stored food called endosperm• Seeds may be in one part

(monocot) or two parts (dicots)

MONOCOT

DICOT

What is the purpose of the fruit?• The main function of the fruit is to disperse the seeds• Dispersal is important because • 1. It spreads the progeny in order to colonize new

environments• 2. Reduces competition for resources with parents• 3. Reduces the chances of predators destroying all of the

plant’s yearly seed production

• Four types of seed dispersal:• A. Self dispersal• B. Wind dispersal• C. Water dispersal• D. Animal dispersal

A. Self dispersal

• Plants disperse their seeds by forceful ejection – explosive fruits!

• Witch hazel, squirting cucumber (jet propulsion)

Self dispersal• The peanut plant sows

(buries) its own seeds!• Geocarpic: carpel grows

inside the earth (soil)

B. Wind dispersal• Fruit and seeds may have special devices

for wind dispersal• Plumes catch wind currents: Dandelion• Trees take advantage of their great heights

for wind dispersal. Fruits with wings are used to slow the descent to land: maple, ash fruit

C. Water Dispersal• Fruits and/or seeds use flotation devices to

travel by water (in rivers, oceans, etc.)• Fruit may have air spaces and corky floats:

for example coconuts.

D. Animal dispersal

• Many plants depend on animals for seed dispersal; they may offer a nutritional reward

• Animals learn to recognize ripened fruit colors

• Fleshy fruits eaten and dispersed with feces

Animal dispersal• Some dry fruit attach and cling to animals

(they hitchhike on the animals)• Some have Velcro-like hooks that cling to

animal fur (burdock, cockleburs)• Others have sticky substances that stick to

host (mistletoe)

A few plant images you should know!

Hormone-producing

cells

Target cells

Movement of hormone

Hormone Action on Plants

A. Plant cells can produce hormones: which are chemical messengers that travel throughout the plant causing other cells called target cells to respond.

B. In plants, hormones control:

1. Plant growth & development

2. Plant responses to environment

Cells in one blooming flower signals other

blooms using hormones to open.

C. Plant cells will send signals to one another to tell them:

1.When trees to drop their leaves.

2.When to start new growth.

3.When to cause fruit to ripen.

4.When to cause flowers to bloom.

5.When to cause seeds to sprout.Leaf Drop

Fruit Ripening

Sprouting Corn Seeds

Cactus Blooming

Tree Budding

D. Ethylene causes Fruit to Ripen

1.Fruit tissues release a small amount of ethlyene

2.Causes fruits to ripen.

3.As fruit become ripe, they produce more and more ethlyene, accelerating the ripening process.

Ethylene released by apples and

tomatoes causes fruit to age quickly.

Plant Tropisms

• 1. Tropism: the way a plant grows in response to stimuli in the environment.

a.Phototropism: growth response to light

-Plants bend towards light

b.Geotrophism or Gravitropism: growth response to gravity

-plant roots grow down with gravity, shoots (stems) grow up against gravity and out of the soil.

c.Thigmotropism: growth response to touch

-vines grow up around trees, venus flytrap closes when leaves are touched

Geotropism

What type of tropism is shown in these pictures?

Thigmotrophism

Thigmotrophism

Geotropism

Phototropism

Phototropism