Plants

Characteristics of all plants

• Are producers and use photosynthesis to make their own food–Most are green because they contain the

pigment chlorophyll• Have eukaryotic cells

–Have a true nucleus–Have cell walls

• Have a cuticle–A waxy layer that covers the parts of a

plant that are exposed to air like leaves and stems

– Is an adaptation for living on land that keeps plants from drying out

Plant Classification

1) Non-vascular plants– Do not have tissues to transport water and

nutrients– Depend on diffusion and osmosis to supply

their cells with nutrients– Cannot grow very tall– Are usually found in moist places– Ex) mosses and liverworts

Moss

Liverwort

2) Vascular plants– Have tube-like structures that transport

water, minerals, and nutrients throughout the plant

– Are divided into two groups• Those that produce seeds

–Divided into two groups: gymnosperms and angiosperms

• Those that do not produce seeds–Ex) ferns, club mosses and horsetails

PLANT CLASSIFICATION

Non-vascular Vascular

Seeds No Seeds

Gymnosperms Angiosperms

Examples

NON-VASCULAR PLANTS

Rhizoids are thin, root-like structures. They anchor the plant. They aren't considered true roots, though, because they lack vascular tissue.

1. Contain a vascular system.

2. They grow in moist, shady habitats.

3. Has underground stems, roots, & large leaves called fronds.

4. Reproduce using spores, not seeds.

The Fern - a seedless vascular plant

There are 11,000

species of ferns.

fiddlehead

frond

• A structure that contains a plant embryo and a supply of food inside a protective covering

Seed

Gymnosperms

• Group of vascular plants • Do not produce flowers• Their seeds are not enclosed by a fruit

1. Most common gymnosperms are Conifers

2. Conifers have leaves called needles or scales have a reduced surface area and thick waxy coat on the needle to reduce water loss and prevents freezing.

Gymnosperms-Conifers

Sequoia

JuniperPine

Conifer Reproduction1. Male cones produce

pollen and the female cone produces eggs and seeds.

2. Pollen is inefficiently transferred by the wind.

3. Once mature, the scales on the female cone dry out and open scattering the seeds by the wind.

Pollen

Pollen Cone

Seed Cone

Angiosperms• Known as flowering plants• Produce seeds within a fruit• Include fruit trees, roses, corn, grass and

oak trees• Are divided into two groups: monocots and

dicots (based on number of cotyledons)– Cotyledon: an embryonic leaf inside the

seed

Monocot characteristics

Dicot characteristics

Parts of The Plant

Functions of the Stem

• Transport water and nutrients from roots to leaves

• Supports leaves, fruit, and flowers• Food storage

Leaves

Important Functions of Leaves

• Photosynthesis– Process that plants use to produce their

food– 6CO2 + 6H2O C6H12O6 + 6O2

• Transpiration– Loss of water and exchange of carbon

dioxide

Leaf Parts

• Blade– Main body of leaf

• Petiole– Attaches blade to

stem• Midrib

– Large central vein

• Apex–Tip of leaf

• Base–Attaches to petiole – if petiole is

absent, attaches directly to stem• Margin

–Edge of leaf

• Epidermis–“Skin” of leaf - responsible for

gas exchange• Stomata

–Outside layer of leaf opening in epidermis where gas and water exchange

• Mesophyll–Middle layer of leaf where

photosynthesis occurs

StructureWide

Helps to catch more light energy

Thin

Help get carbon dioxide from bottom to top of leaf for photosynthesis

Leaf structure

Greener on top

CO2 gets in here

Leaf diagram – palisade layer

CO2

Most chlorophyll

Leaf cell - palisade

Position?Upper surface of

leafFeatures?Box shape

ChloroplastsFunction?

Photosynthesis

Gas exchange

• Leaves are designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf

• They have small holes called stomata on the under surface

• Each hole is open & closed by 2 guard cells

Stoma position

Stoma is a small holeIts size is controlled by 2 guard cells

closed open

Stoma function is for gas exchange in the leaf

Carbon dioxide

oxygenGuard cell

Provided plant is photosynthesising

Stomata open and close at different times of the day

When it is light the plant needs CO2 for photosynthesis so the stoma open

At night (darkness) they close

Gas exchange

Root Functions

• Absorption of water and nutrients– performed by root hairs

• Transportation of water and nutrients to stem

• Anchor plant to maintain stability• Store food and water

Roots have 4 primary functions

Parts of the Root

• Epidermis– Outermost layer of cells, like the skin of

the root

• Cortex– Tissue inside epidermis that stores starch

and other substances for the growth of the root

Root Types

2. Tap Roots –larger central root reaches deep water sources underground

Ex. Trees, Carrots, & Dandelions

1. Fibrous Roots: branching roots hold soil in place to prevent soil erosion

Ex. Grasses

Tap Root

Can you identify these root types?

Parts of a flower

Flower Function

• Flowers are pollinated by:–Wind– Insects–Birds

Sexual Reproduction!!!!

Flower Parts• 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

Flower Parts• Stamen: male reproductive structure

a.Filament: thin stalk; supports antherb.Anther: knob-like structure;

produces pollen c.Pollen: contains microscopic cells

that become sperm cells

Reproductive Organs

Close up of stigma, style and anthers in a tulip

Flower Parts• Petals

– Highly colored part of the flower, may contain perfume and/or nectar glands

• Sepals– Small green

structures on the base of a flower that protect the flower bud

Parts of the flower

Fruit

• A ripened ovary that contains angiosperm seeds

• Function: to hold and protect the seeds• Ex) corn, peach, tomato, pea, apple

Fruit can aid in dispersal of seed to reduce competition with parent plant.

1. Winged fruit – glides to new location (maple fruit)

2. Floating fruit – can float to new locations (coconut)

3. Fleshy fruit - sweet bright colored fruit have seeds that survive the digestive system of animals that eat the fruit (apple)

4. Spiny fruit- Velcro like projections attach to the fur of animals (cockleburs)

Maple seeds: Winged fruit

Burdock: Spiny fruit

Bill Nye flowers video

• http://www.youtube.com/watch?v=OpzvKdmAoI0

http://www.youtube.com/watch?v=HD8L83LOy4k

• Bill Nye video on plants

Plant Tropisms

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: 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

http://www.youtube.com/watch?v=zmxY6aD7ltM&playnext=1&list=PL94468D2FF60A9CD3&feature=results_main

Geotropism

What type of tropism is shown in these pictures?

Thigmotrophism

Thigmotrophism

Geotropism

Phototropism

Phototropism