Plants

Did you know…

•Roughly 80% of US money contains traces of cocaine.

Did you know

• If you added up every blink in your lifetime and used them all at once your eyes would be closed for 1.2 years

What we already know…

• Multicellular

• Eukaryotes

• Autotrophs

• Cell walls contain cellulose

• Photosynthesis occurs in chloroplasts using the pigment chlorophyll

Plant Life Cycle: Alternation of Generations

• 2 alternating phases

1. diploid (2N) – called the

sporophyte, produces spores

2. haploid (N)- called the

gametophyte, produces gametes

Alternation of Generations

What plants need to survive

1. Sunlight

2. Water and Minerals

3. Gas exchange

4. Movement of water and nutrients

Early PlantsEvolved from green algae – member of the kingdom Protista, a small plantlike protist.

Early plants were still restricted to very wet areas due to the lack of true roots

5 Major Plant Groups in the Plantae Kingdom

NONVASCULAR VASCULAR

Mosses Seedless Seed(produce spores)

Ferns (produce spores)

Gymnosperm Angiosperm

(seeds in cones) (seeds in flowersand fruit)

Monocot Dicot

Remember this chart!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

• VASCULAR TISSUES – specialized cells that transport water and other materials. Found almost all land plants. Allows materials to be distributed more efficiently.

• NONVASCULAR – relatively small plants that have no vascular system.

How plants are grouped:

1. The presence or absence of vascular tissue.

2. Their method of reproduction.

BRYOPHYTES:

Mosses, Hornworts and Liverworts

Characteristics of Bryophytes

• Life cycle depends on water for reproduction

• No vascular tissue, draw up water through osmosis, lack roots – have RHIZOIDS: long, thin cells that anchor

them into the ground.• Low growing, small• Found in moist, shaded areas

Important tems

• Archegonia – female sex structure, where eggs are produced – much like the ovary

• Antheridia – male sex structure that produces sperm

• Sometimes both structures are found on the same plant, others are on separate plants.

Vascular Plants

Called Tracheophytes: ferns, gymnospermsand angiosperms• Evolution of vascular tissue, developed a

new cell that allowed them to conduct water

• TRACHEIDS: hollow cells with thick cell walls that withstand pressure. Allow water to move more efficiently than osmosis. Connected end to end like drinking straws

Vascular Tissues

• Allow plants to move substances against gravity.

• XYLEM: transports water upward from the roots to the rest of the plant

• PHLOEM: transports nutrients and carbohydrates produced by photosynthesis from the leaves downwards to the rest of the plant

Seedless vascular plants

• Club mosses (P:lycophyta)–small plants that live in moist woody areas, near streams

Seedless vascular plants cont.• Horsetails-(P:arthrophyta) commonly called

Equisetum or horsetails,

once used to scour pots

and pans in colonial times

because stems contain silica

Ferns: Phylum Pterophyta

• Seedless vascular plants

• Second largest phylum of the plant kingdom

• Over 20,000 species

• Creeping underground stems called rhizoids

Ferns

• Do not have seeds, have spores, found on the underside of the leaf.

• Leaves are called fronds.

• 1ST appeared 400 million years ago.

Clusters are called sori (sorus) – individual clusters are called sporangia

1. What are the two types of vascular tissue?

2. What are the three phyla of seedless vascular plants?

3. What is the dominant stage of the fern life cycle?

4. What process is going on inside clusters of sori?

5. How is water essential to the life cycle of bryophytes?

6. What is the female reproductive structure located in the gametophyte called? Male?

7. What characteristic of bryophytes is responsible for their small size?

Seed Plants

• Divided into 2 groups, Gymnosperms and Angiosperms

• Success is due to three things

1. water is not needed to reproduce

2. transfer of sperm is done by pollination

3. embryos are protected in seeds.

Types of Vascular Plants: Seed = Gymnosperm

• Plants whose seeds do not develop within a sealed container (fruit).

• Means “naked seed”• Sperm is carried by the

wind.• Ex. Pine trees, cycads,

conifers, palm trees.

.

GYMNOSPERMS

TVhe Svalbard Global Seed ault is seen Monday Feb. 25, 2008 in Longyearbyen, Norway. A 'doomsday'

vault built to withstand an earthquake or nuclear strike is ready to open deep in the permafrost of an Arctic mountain, where it will protect millions of agriculture

seeds from man-made and natural disasters. The vault is to be officially inaugurated on Tuesday, less than

year after crews started drilling in Norway's Svalbard archipelago, about 1,000 kilometers (620 miles) from the North Pole. The vault has the capacity to store 4.5 million seed samples from around the globe, shielding them from climate change, wars, natural disasters and

other threats.(AP Photo/John McConnico)

• Place everything against the wall except your notes book and something to write with.

FLOWERS:

Advantages of flowers

1. Allows plants to reproduce without water.

2. Aid in attracting pollinators.

3. Aid in dispersal of seeds (fruit)

4. Holds reproductive structures.

FLOWERS

Flowers

Consist of 4 specialized leaves Petal – attracts insects and other

pollinators to the plant. Sepal – outermost leaf that

encloses the bud before it opens, protects developing seeds

Flowers: FEMALE Reproductive Structures

Called the 3. PISTIL or CARPEL. Contains the ovary. Female gametophyte

PARTS OF THE PISTIL1. Stigma – sticky top that grabs the pollen2. Style – the stalk of the ovary3. Ovary – swollen lower portion where ovules develop. Where fertilization occurs.4. Ovules – eggs- become the seeds after fertilization

Flowers: MALE Reproductive Structures

4. STAMEN. Male gametophyte

Parts of the stamen:

Anther – produces pollen, site of meiosis

Filament – supports the anther

How Reproduction Occurs in Flowers

1st – POLLINATION - pollen (male) is transferred from the anther to the stigma.

2nd – Male pollen sprouts a pollen tube that connects to the ovule and allows the sperm to go directly to the egg.

3rd – FERTILIZATION- The sperm and egg join

Fruit Formation

Following fertilization:

Ovary walls thicken to form a fruit to enclose the developing seeds.

SEEDS• Structure that contains the embryo of the plant.• All seeds have four main characteristics:

1. Protection – seed coat keeps the seed from drying out and protects from injury/disease.

2. Nourishment – nutrients are stored within the seed.

3. Plant dispersal – spread by wind, water, or animals. Prevents competition between the parent and the offspring.

4. Delayed growth – most seeds will not sprout until the conditions are favorable. Allows plants to survive drought or cold winters.

PARTS OF A SEED

endosperm

Dicot seed

PARTS OF A SEED

1. Hypocotyl – connects cotyledon and radicle

2. Epicotyl - will become the shoot (contains stems and leaves

3. Cotyledon – leaf-like structures4. Seed coat – outermost layer, serves as

protection5. Radicle – embryonic root6. Embryo – developing offspring that the

seed protects.7. Endosperm – provides nutrients to the

embryo

How seeds grow: Seed Germination

• Germination occurs when the seed has good growing conditions.

• Water enters the seed causing the tissues to swell and the seed coat to break.

• If enough water is present it causes the seed to grow.

• The first root and stem emerge.

Why Fruit?

Main goal is seed dispersal.

Animals eat the fruit and then eliminate far away from the parent plant.

This decreases competition of the parent and offspring.

Fruits vs. Vegetables

•FRUITS HAVE SEEDS•VEGETABLES DO NOT HAVE

SEEDS, THEY ARE EITHER FLOWERS OR MODIFIED ROOTS, STEMS OR LEAVES.

Roots, Stems and Leaves

• Plants are made up of 3 principal organs: roots, stems and leaves

Plant Tissue Systems

• 3 types:1. Dermal tissue – outer covering of

plant consists of a single layer of epidermal cells. Usually covered by a thick waxy coating called the cuticle

Trichomes – cells with tiny projections making the leaf appear hairy

Guard cells- in epidermal layer on underside of a leaf, regulate water loss

Vascular Tissue

• Moves water and nutrients through the plant

• Several types of specialized cellsXYLEM – cells are called tracheids

(found in angiosperms and gymnosperms)Vessel elements – found only in

angiosperms, wider than trachieds. Look like stacked tin cans. Allows for continous flow

Functions of ROOTS

• Anchor the plant

• Hold soil in place and prevent erosion

• Transport water and nutrients

• Holds plants upright

3 Main organs of a Plant

1. ROOTS

2. STEMS

3. LEAVES

1. Roots: Major Functions

1. Anchor plant.

2. Absorb water and mineral nutrients.

3. Function as storage in some plants.

1. Roots: 2 Types

1. Taproot system– large central root, with smaller roots branching off. Serves as storage .Ex. Carrots and radishes

2. Fibrous root system – highly branched root system.

How water and nutrients enter the root:

1. Osmosis – roots take in water from the soil by osmosis.

2. Active transport – movement of nutrients through the plant, requires energy.

Roots

2. Stems: Major Functions

1. Support the leaves and house the vascular tissue.

2. Serves as a highway that transports materials to the leaves and roots.

Adaptations of Stems These functions include nutrient storage,

reproduction and protection. 6 Main types:

1. Runner – Airplane plant

2. Bulb – onion, daffodil

3. Corm - gladiolus

4. Rhizome – Ferns, strawberries

5. Tuber – potatoes, caladiums

6. Thorns

Adaptations of Stems

Stems

3. Leaves: Major Functions

1. Photosynthetic organ of the plant – collects energy from the sun.

2. Manufactures food.

3. Leaves: Parts1. Cuticle – waxy covering on the outside of the

leaf that decreases the rate of water evaporation.

2. Epidermis – layer of cells found below the cuticle that also prevent water loss.

3. Stomata- tiny holes in the epidermis that allow for air exchange.

4. Guard cells – specialized cells that “guard” the opening and closing of the stomata based on the climate.

5. Mesophyll – cells found in the leaf – 2 distinct layers.

6. Veins – made up of xylem and phloem, vascular bundles.

3. Leaves: Mesophyll

1. Spongy mesophyll – inner layer of loosely packed irregular shaped cells, contain the vascular bundles.

2. Palisade mesophyll – where photosynthesis actually occurs. Large column shaped cells that contain many chloroplasts.

Leaf structures

                                                                                                                                                                                              

  

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Adaptations of Leaves