Plants & Photosynthesis

A Dr. Production

Why Study Plants?• Oxygen can you breathe?

• Ozonedo you tan, burn or melanoma?

• Carbohydrates do you have food to eat?

• Fiber are you regular?

• Wood where do you live

• Fossil fuels do you drive or stay warm in the winter?

• Latex ever use plastic?

• Medicinesever get sick?

• Pitch do you like your furniture varnished & painted?

• Resins ever float a boat?

• Flavors & fragrancesdo you like tasteful aromatic food?

• Jobs…

Careers in Horticulture:

• Pomology-fruits• Viticulture-grapes• Enology-wine• Olericulture-vegetables• Ornamental Horticulture-

landscape plants• Landscape Architecture-

design

1. Vascular tissue?No…………Bryophyte

Yes………..Tracheophyte, go to 2

2. Seeds? No…………Seedless plant

Yes………..Seed plant, go to 3

3. Covered Seeds? No…………Gymnosperm

Yes………..Angiosperm, go to 4

4a. One cotyledon, parallel veins, 3X flowers, 1 pore pollen, scattered vascular bundles, fibrous roots

Yes……….……monocot

4b. Two cotyledons, netted veins, 4X/5X flowers, >3 pored pollen, ringed vascular bundles, taproots

Yes………..…..dicot

What types of plants are there?

Alternation of Generations

• Plants (as all sexually reproducing organisms) spend part of their life haploid (gametophyte) and part of their life diploid (sporophyte).

Avascular Plants : Avascular Plants : Mosses, Hornworts & , Hornworts & LiverwortsLiverworts

Life Cycle of a Moss

Seedless Vascular Plants : Seedless Vascular Plants : Ferns, Club mosses, , Club mosses, HorsetailsHorsetails and Whisk ferns and Whisk ferns

Ferns are seedless plants whose flagellated sperm require moisture to reach the egg

The life cycle of a fern

Figure 29.11xa Life cycle of a fern: mature fern (diploid sporophyte)

Life cycle of a fern: gametophyte

• Ferns and other seedless plants once dominated ancient forests– Their remains formed coal

Seedless plants formed vast “coal forests”

Egg (n)

1

HAPLOIDDIPLOID

Sperm (n)

Male gametophyte(pollen grain)

Female gametophyte (n)

Zygote(2n)

Seedcoat

Embryo(2n)

Seed

Sporophyte

Scale

Sporangium(2n)

Ovule

Integument

MEIOSIS

HAPLOIDPollen grains(malegametophytes)(n)

MEIOSIS Fertilization

Female conebears ovules.

2 Male cone producesspores by meiosis;spores develop intopollen grains

3 Pollination

4 Haploid spore cells inovule develop intofemale gametophyte,which makes egg. 5 Male gametophyte (pollen)

grows tube to egg andmakes and releases sperm.

6 Zygote developsinto embryo, andovule becomesseed.

7 Seed falls toground and germinates,and embryo grows into tree.

Life Cycle of a Gymnosperm

HAPLOID

DIPLOID

Egg (n)

Ovule

Stigma

Pollengrain

Pollentube

Sperm

Fertilization

Seedcoat

Embryo(2n)

Seeds

Sporophyte

Ovary

Ovule

Pollen (n)

Meiosis

1 Haploid sporesin anthers develop

into pollen grains: male gametophytes.

2 Haploid spore in eachovule develops intofemale gametophyte,which produces egg.

3 Pollinationandgrowthof pollentube

4 Zygote(2n)

5 Seed

6 Fruit

7 Seed germinates,

and embryo grows into plant.

Food supply

Life Cycle of an Angiosperm

Bryophytes

Tracheophytes

Seedless Plants GymnospermsAngiosperms

What is it?

1. 6.

2. 7.

3. 8.

4. 9.

5. 10.

What is Photosynthesis?

Photosynthesis is using light energy from the sun to make sugar

Light E + CO2 + H2O C6H12O6 + O2

Photosynthesis occurs in the chloroplasts of autotrophs

Light Reactions occur in the thylakoid membrane of the chloroplast

Light reactions use light energy and water to produce: ATP

Hydrogen (NADPH)

Oxygen (as waste)

The dark reactions are also called the Calvin Cycle or Carbon Fixation

Dark reactions occur in the stroma of the chloroplasts

They use energy to store it in the form of a sugar for later use

Special plants called C4 plants, or CAM plants have specialized systems of photosynthesis

CAM.qt

Leaf Anatomy LeafWeb qt Anatomy

derm

Opening & Closing of Stomata

Stem Anatomy

Transport through Vascular Tissue• Xylem Wxyz Water

• Phloem phood by photosynthesis

FoodWeb qt Source & Sink

Water&PlantsWebqt Water movement

Root Anatomy

Root Anatomy

Flowers

• The flower is the centerpiece of angiosperm reproduction

• Double Fertilization

STAMEN

Anther

Pollen grains

Stigma

Ovary

CARPEL

PETAL

SEPALOvule

Fruit• After fertilization the ovary matures into a

fruit. In general fruits may be classified as simple, aggregate or multiple ).

• Angiosperm fruit has 2 functions:

1. Protect the seeds during their maturation2. Effectively disperse the mature seeds

ripening.qt Tomatoes

seed.qt

• Fruits are adaptations that disperse seeds

The structure of a fruit reflects its function in seed dispersal

SeedsWith double fertilization the following occurs:

1. The zygote develops into an embryo2. The integuments develop into a seed coat 3. The ovary develops into a fruit4. The primary endosperm nucleus divides to form endosperm

Germin.qt

Maizegr.qt Geotropism

Maizepho.qt Geotropism

Plant Responses (Tropisms)Tropisms vs Taxisms

Thigmotropism Physical Contact. Chemotropism Chemicals Thermotropism Temperature Traumotropism Wounding Electrotropism Electricity Skototropism Dark Aerotropism Oxygen Gravitropism GravityPhototropisml t igh

Plants in MotionTropisms

Mimosa, Sundew

Plants Can Tell Time

• Circadian Rhythms

Silk Tree

Sleep Movements in Legume

Plant Defenses

• Physical thorns, spines, hairs

• Chemical poisons, irritants, medicines

• Ingestibilitycellulose

• Mechanical thigmotropism

• Systemic Defense Against Herbivores

Plant HormonesHormone: a chemical substance effective in small

quantities, that is produced one place and has its effects elsewhere

• Auxinsroot formation, apical dominance

• Giberellins seed germination, stem elongation

• Cytokinins cell division, differentiation

• Abscisic Acid ab secare plant maturation, leaf abscission (what time of year?)

• Ethylene leaf abscission, one bad apple…

Cucumber Cytokinins

Strawberry Ripening

• Gymnosperms supply most of our lumber and paper

• Angiosperms provide most of our food – Fruits, vegetables, and grains

• Angiosperms also provide other important products– Medications, fiber, perfumes

Agriculture is based almost entirely on angiosperms

• Angiosperms are a major source of food for animals– Animals also aid plants in pollination and seed

dispersal

Interactions with animals profoundly influenced angiosperm evolution (Coevolution)

• 20% of the tropical forests worldwide were destroyed in the last third of the 20th century

• The forests of North America have shrunk by almost 40% in the last 200 years

Connection: Plant diversity is a nonrenewable resource

• Some plants in these forests can be used in medicinal ways

– More than 25% of prescription drugs are extracted from plants

References• Plant Anatomy: BIO 102

• http://generalhorticulture.tamu.edu/HORT604/LectureSuppl/AnatomyOrgans/AnatomyOrgans05.htm

• Plants in Motion Movies:

• The Life Wire Textbook Animations

• Biology I Tutor Vista Animations

• Plant Curriculum Links

• 4 Types of Plants Video

• The World of Plants: Plants & People Video

• Science of Life; The World of Plants

• Tour of a Plant Cell Study Guide