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Plants & Photosynthesis A Dr. Production. Why Study Plants?. Oxygen can you breathe? Ozone do 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?
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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
Alternation of Generations • Plants (as all sexually reproducing organisms) spend part of their life haploid (gametophyte) and part of their life diploid (sporophyte).
Seedless Vascular Plants : Ferns, Club mosses, Horsetailsand Whisk ferns Ferns are seedless plants whose flagellated sperm require moisture to reach the egg
Figure 29.11xa Life cycle of a fern: mature fern (diploid sporophyte)
Seedless plants formed vast “coal forests” • Ferns and other seedless plants once dominated ancient forests • Their remains formed coal
Female gametophyte (n) 4 Haploid spore cells inovule develop intofemale gametophyte,which makes egg. 5 Male gametophyte (pollen)grows tube to egg andmakes and releases sperm. Egg (n) Sperm (n) Male gametophyte(pollen grain) HAPLOID MEIOSIS Fertilization DIPLOID Scale Sporangium(2n) Ovule Seedcoat Zygote(2n) 3 Pollination Embryo(2n) HAPLOIDPollen grains(malegametophytes)(n) Integument 1 Female conebears ovules. 6 Zygote developsinto embryo, andovule becomesseed. MEIOSIS Seed 2 Male cone producesspores by meiosis;spores develop intopollen grains 7 Seed falls toground and germinates,and embryo grows into tree. Sporophyte Life Cycle of a Gymnosperm
Stigma 2 Egg (n) Haploid spore in eachovule develops intofemale gametophyte,which produces egg. 3 Pollinationandgrowthof pollentube Pollengrain Pollentube Ovule 1 Haploid sporesin anthers developinto pollen grains: male gametophytes. Sperm Pollen (n) HAPLOID Meiosis Fertilization DIPLOID 4 Zygote(2n) Seedcoat Food supply Seeds 7 Ovary Seed germinates,and embryo grows into plant. Ovule Embryo(2n) 5 Seed Sporophyte 6 Fruit Life Cycle of an Angiosperm
Bryophytes Tracheophytes Seedless PlantsGymnospermsAngiosperms
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
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
They use energy to store it in the form of a sugar for later use
CAM.qt Special plants called C4 plants, or CAM plants have specialized systems of photosynthesis
Leaf Anatomy LeafWeb qt Anatomy derm
Transport through Vascular Tissue • Xylem Wxyz Water • Phloem phood by photosynthesis FoodWeb qt Source & Sink Water&PlantsWebqt Water movement
Pollen grains Anther Stigma CARPEL Ovary STAMEN PETAL Ovule SEPAL Flowers • The flower is the centerpiece of angiosperm reproduction • Double Fertilization
Fruit ripening.qt Tomatoes • 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 seed.qt
The structure of a fruit reflects its function in seed dispersal • Fruits are adaptations that disperse seeds
Seeds Germin.qt With 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 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 Gravity Phototropism light Plants in Motion Tropisms Mimosa, Sundew
Plants Can Tell Time • Circadian Rhythms Sleep Movements in Legume Silk Tree
Plant Defenses • Physical thorns, spines, hairs • Chemical poisons, irritants, medicines • Ingestibilitycellulose • Mechanical thigmotropism • Systemic Defense Against Herbivores
Plant Hormones Hormone: 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 Acidabsecare plant maturation, leaf abscission (what time of year?) • Ethylene leaf abscission, one bad apple… Cucumber Cytokinins Strawberry Ripening
Agriculture is based almost entirely on angiosperms • 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
Interactions with animals profoundly influenced angiosperm evolution (Coevolution) • Angiosperms are a major source of food for animals • Animals also aid plants in pollination and seed dispersal
Connection: Plant diversity is a nonrenewable resource • 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
More than 25% of prescription drugs are extracted from plants • Some plants in these forests can be used in medicinal ways
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