Chapter 23

Section 3: Plants in Our Lives

Introduction to PlantsSection 1: Adaptations of Plants

Section 2: Kinds of Plants

Plant Structure & function

The Plant Cell- review• Are plants autotrophic or heterotrophic?

– Autotrophic (remember, plants are producers and they make their own food via photosynthesis)

• Are plants prokaryotic or eukaryotic?– Eukaryotic (remember, eukaryotes have nuclei just like

we do and YOU are EUkaryotes)

• Are plants multicellular or unicellular?– Multicellular!

• Plant cell walls are made of….– Cellulose

The Plant Cell:Label!

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 (vascular) and tracheophytes (nonvascular); 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

Section 1

Adaptations of PlantsEstablishment of Plants on Land

• Absorbing Nutrients • To survive on land, plants evolved

the ability to absorb mineral nutrients from the soil.

• Preventing Water Loss • To survive on land, plants evolved a

waxy outer covering called a cuticle, and stomata and guard cells for gas exchange, to prevent their bodies from drying out.

• Reproducing on Land • To survive on land, plants use pollen

to reproduce without water and transmit male gametes.

http://en.wikipedia.org/wiki/Image:Devils_Punchbowl_Waterfall%2C_New_Zealand.jpg

Section 1

• Advantages of Conducting Tissue • Vascular plants have a system of

well-developed tissues that transport water within a plant.

• Advantages of Seeds • Seeds protect and nourish a plant’s

embryo, disperse the offspring, and delay the growth of the embryo until conditions are favorable.

• Advantages of Flowers • Flowers make reproduction more

efficient by promoting pollination.

Adaptations of Plants Vascular Tissue, Seeds, and Flowers

http://upload.wikimedia.org/wikipedia/commons/4/46/Diversity_of_plants_image_version_3.png

Section 1

Adaptations of Plants Plant Life Cycles

• The Vascular-Plant Sporophyte – The sporophytes of vascular plants have a vascular

system. Their bodies consist of an aboveground shoot and an underground root.

http://en.wikipedia.org/wiki/Sporophyte

More Vocabulary Seed- adaptation to terrestrial life composed of a plant embryo, stores food and contains a protective coat

Cone- reproductive structure of gymnosperms; contains pollen in males and ovules in females

Ovulate cone- from a pinetree (female)

Staminate cone- from a pinetree (male)

Flower- reproductive structure of angisperms composed of 4 sets of modified leaves

Fruit- mature ovary of a flower that protects dormant seeds and aids in their dispersal

Cotyledons – nonphotosynthetic leaves of an immature plant; provide source of nutrients until plant can produce its own food

Kinds of PlantsNonvascular vs. Vascular

• Nonvascular plants do not have a system for transporting water and other nutrients within their body

• Vascular plants are plants that contain structures with vascular tissue (roots, stems and leaves)– Seedless plants– Seed plants

• Gymnosperms and Angiosperms

Section 2

Kinds of PlantsNonvascular Plants

• Key Features of Nonvascular Plants – Nonvascular plants are small and lack vascular tissue (roots,

stems and leaves).• Kinds of Nonvascular Plants.

– Mosses, liverworts, and hornworts are nonvascular plants.

http://en.wikipedia.org/wiki/Image:Anthoceros_levis.jpg

Bryophytes – nonvascular plants

Moss Hornwort

Liverworts

20 mm

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

Section 2Kinds of Plants

Seedless Vascular Plants

• Key Features of Seedless Vascular Plants– Seedless vascular plants produce

spores with thickened walls that prevent them from drying out.

• Kinds of Seedless Vascular Plants – Ferns, club mosses, horsetails,

and whisk ferns are seedless vascular plants.

http://en.wikipedia.org/wiki/Image:Lycopodium_plant.jpg

Whisk fern horsetail fern

Tracheophytes – vascular plants

• Seedless plants –whiskferns, horsetails, and ferns

Seedless vascular plants – ferns

- reproduce with spores

- diagram shows spores growing in clusters called sori on the back of the fern

Seedless vascular plants dominated during the Carboniferous period.

Section 2

Kinds of PlantsGymnosperms

• Key Features of Gymnosperms – Gymnosperms are seed plants that produce cones.

• Kinds of Gymnosperms – Conifers, cycads, ginkgoes, and gnetophytes are gymnosperms.

http://en.wikipedia.org/wiki/Image:Welwitchia.jpg

Ginkgo Cycad

Tracheophytes – vascular plants• Seed plants

• Gymnosperms – have seeds in cones; include: ginkgos, cycads, gnetophytes,

and conifers

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

Section 2

Kinds of PlantsAngiosperms

• Key Features of Angiosperms – Angiosperms are seed plants that produce flowers and fruits.

• Kinds of Angiosperms – The angiosperms are classified as either monocots or dicots.

http://upload.wikimedia.org/wikipedia/en/7/78/WIKI-Grass.jpg

Monocots vs. Dicots• Monocots:

– One cotyledon– Veins parallel– Vascular bundles in

complex arrangement– Fibrous root system– Floral parts in

multiples of three– Ex. Iridaceae (irises),

Liliaceae(lilies) and Poaceae (grass).

• Dicots:– Two cotyledon– Veins netlike– Vascular bundles

arranged in ring– Taproot usually

present– Floral parts in four or

five– Ex. Asteraceae

(composite), Brassicaceae (mustard), Fabaceae (legume), and Rosaceae (rose),

Subgroups of Angiosperms:Monocots & Dicots

Tracheophytes – vascular plants

* Seed plants

• Angiosperms – flowering plants - have flowers,

fruits, and seeds

Grass flowers

Grasses are flowering plants, too. So are trees.

Flowerpistil

Section 3

Plants in our LivesPlants as Food

• Fruits and Vegetables – All types of plant parts—roots, stems, leaves, flowers, fruits,

and seeds—provide food for humans.• Root Crops

– Root crops, such as potatoes, grow underground.• Legumes

– Legumes, such as peas, produce protein-rich seeds in long pods.

Section 3

Plants in our LivesCereals

• Wheat – For more than one-third of the world’s population, wheat

is the primary source of food.• Corn

– Corn is the most widely cultivated crop in the United States.

• Rice – For more than half of the people in the world, rice is the

main part of every meal.

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!

Section 3

Plants in our LivesNonfood Uses of Plants

• Wood – Wood is a source of wood pulp used for making

paper, lumber used for building materials, and fuel.• Medicines

– Many important medicines are currently made from plants or were originally derived from plants.

• Fibers – Plant fibers are used to make paper, cloth, and rope.

The most important sources of plant fibers are wood and cotton.

http://upload.wikimedia.org/wikipedia/commons/0/0b/Taxus_wood.jpg

We don’t just eat plants, we also wear them, build with them, and use them for medicines!

Plant Structure & Function

Chapter 25Pg. 551 - 564

More Review

Do you remember the equation for photosynthesis

6H2O + 6CO2 + sunlight 6O2 + C6H12O6

Do you remember what organelle photosynthesis takes place in?

The Chloroplast

Plant Structure

• Plants are composed of:– Tissue– Roots– Leaves– Stems

Each plant part – tissue, root, stem, leaf - has a specific role in keeping the plant alive through photosynthesis

Structure:Tissues- 3 typesVascular Plant Body

A vascular plant’s body contains three kinds of tissues—dermal tissue, ground tissue, and vascular tissue.

– 1.Dermal Tissue Dermal tissue covers a plant. A thin layer of epidermis covers nonwoody parts. Several layers of cork cover woody parts.

– 2.Ground Tissue Ground tissue is specialized for photosynthesis in leaves and for storage and support in stems and roots.

Review: Vascular Tissues

– 3.Vascular Tissues Vascular tissue conducts water, minerals, and organic compounds throughout the plant.• Xylem - contains vessels, which are made up of

cells that conduct water only after they lose their cytoplasm. Water flows between cells through pits and perforations in their cell walls.

– Carry reactants• Phloem -contains sieve tubes, which are made up of

cells that are still living. Substances pass between the cells through pores.

– Carry products

Plant Structure:Roots

• Function- absorption, storage and anchorage• Roots have a central core of vascular tissue that is

surrounded by ground tissue and epidermal tissue. • Root hairs on root tips increase the surface area which

increases absorption• Remember that Nitrogen Fixation happens in the roots!

(Nitrogen fixation is when nitrogen in theatmosphere is converted by bacteria into nitrogen compounds like ammonia, nitrates and nitrites)

Plant Structure:Leaves

• Site of photosynthesis• composed of blade, veins, petiole• There are different layers of leaves (next slide)• simple or compound

Leaves Cross Section

- epidermis – adaptation for terrestrial life- covering of leaf

- waxy cuticle - coats upper and lower epidermis

- stomata – site of transpiration

Movement of Water :

• Transpiration Transpiration, the loss of water from a plant’s leaves, creates a pull that draws water up through xylem from roots to leaves.

• Guard Cells and Transpiration Guard cells control water loss by closing a plant’s stomata when water is scarce. Thus, they also regulate the rate of transpiration.

Movement of Organic Compounds

• Translocation Organic compounds are pushed through the phloem from a source to a sink in a process called translocation.

See pg. 559 – Yes, you need to know the layers of leaves

• Function: support and transfer• Contain the Xylem and Phloem• Help define plant types (shrubs, vines, trees, etc)

Plant structure:Stems

Chapter 25

Plant Structure and Function

Leaves lose water by

transpiration.

Leaves produce sugars in

photosynthesis.

Sugars are transported

downward in the stem.

Sugars are transported into flowers and fruits.

Sugars are transported upward to leaf buds in the

spring.

Water enters the xylem of roots and moves upward into the xylem of the

stem.

Sugars are transported

downward into roots for use or storage.

Overview of plants and photosynthesis happenings