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Importance of Plants

Importance of Plants . Plants define biomes Forest Prairie Desert Plants adapted to land before animals. Plants sustain animal life. Evolution of Plant Adaptation to Land. 500M+ years: Moss: nourish embryo 430M years: Ferns: water & nutrient transport

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Importance of Plants

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  1. Importance of Plants Plants define biomes • Forest • Prairie • Desert Plants adapted to land before animals. Plants sustain animal life

  2. Evolution of Plant Adaptation to Land 500M+ years: Moss: nourish embryo 430M years: Ferns: water & nutrient transport 400M years: Gymnosperms (pine): seeds in cones 200M years: Angiosperms(flowers) attract pollinators fruit contain seed

  3. Importance to Humans Food Wheat, rice, corn Fiber Cotton Feed Livestock Construction Lumber Energy Ethanol, E85, Biodiesel Health Aspirin (White Willow bark) Pyrethrum (chrysanthemum) Antibiotics

  4. Asexual Reproduction in Plants Meristem Tissue: All mitosis! Stolons: aboveground stem strawberry Rhizomes: underground stem, iris Tubers: portion of rhizome, potato Corm: underground stem, gladiolus Bulb: modified leaf, onion Plantlets: maternity plant Cuttings: pineapple, sugarcane Grafting:fruit trees, grapes

  5. Cut Flower Market in U.S. $$$$$ Per Capita Consumption Switzerland 101.4 vs U.S. 25.9 Top Cut Flower Rose U.S. Imports Columbia and Ecuador Cut Flower Purchases Florists = 21.9% Supermarkets = 49.0%

  6. Death of a Cut Flower Flowers Strive to Reproduce Respiration increases  heal wound Water uptake stops  air blocks uptake Hydrating solution (Sprite?) for shipping Citric acid lowers pH  faster water uptake Disinfectant  protects flower Sugar (20%)  food source Cold storage  slows respiration After 1 week: Lower leaves lost first Scent production decreases Petals begin to shed

  7. Types of Flowering Plants Monoecious: male and female flowers on same plant Corn, oak, cucumber, watermelon Dioecious: male and female flowers on separate plants honey locust, willow, holly, cannabis

  8. Types of Flowering Plants • Monocotyledon (Monocot) • 1 cotyledon (seed leaf) • Flower parts in 3’s • Parallel leaf veins • Eudicotyledon (Eudicot) • 2 cotyledons • Flower parts in 4’s or 5’s • Net leaf veins

  9. Anatomy of a Flower Flower have 4 whorls of modified leaves.

  10. Anatomy of a Flower • Simple Fruits: • Single carpels • Peas, beans, corn • Compound Fruits: • Fused carpels • Raspberry, strawberry • F Day Lilly

  11. Alternation of Generation in Flowering Plants Diploid (2n) Sporophyte = plant you can see Megasporocyte Microsporocyte Meiosis Megaspores Microspores Mitosis Female Gametophyte Male Gametophyte Embryo Sac Pollen Grain (egg) (sperm) Haploid (1n) Gametophyte = multicelled gamete

  12. Pollen Production Anther 4 Pollen Sacs (2N) Meiosis  Microspores (1N) Mitosis  tube cell generative cell Mitosis2 sperm Pollen = 3 celled Male Gametophyte

  13. Egg Production Ovary & Ovule (2N sporophyte) meiosis  4 spores Megaspores (1N) 1 of 4 survive mitosis  8 nuclei cytokinesis  7 cells embryo sac = female gametophyte • 3 antipodals • 1 central cell with 2 polar nuclei • 2 synergids • 1 egg

  14. Pollination Pollen  stigma • Artificial: • Cross-pollination: pollen from different plant Self-pollination: pollen from same plant

  15. Fertilization Pollen Grain: • lands on stigma • germinates • forms pollen tube • grows between cells to the ovule. Double fertilization occurs. • 1 sperm + egg = zygote (2N) • 1 sperm + 2 polar nuclei = 3N endosperm cell.

  16. Embryo Development • Cell Division: Zygote divides: small cells  embryo larger cells  suspensor • Cell elongation: growth • Differentiation: tissue and organs Meristem: Embryonic tissue Active cell division Root Tip: Shoot Tip: Lateral:

  17. Seed Germination Seed: respiration and metabolism low Germination: • Embryo resumes normal growth and metabolism • Dormant period • Growing conditions: • Oxygen: metabolism • Adequate Temperature: enzymes • Adequate Moisture: hydration • Light: stimuli

  18. Monocot and Eudicot Seed Corn Bean • Endosperm (3n): provides nutrients to embryo. • Mainly starch. Cotyledons (2n) feed embryo. Mainly oils and protein • Liquid starch (coconut, sweetcorn) has cell wall formation delayed.

  19. Seed Dispersal Dispersal: • Wind • Maple tree, dandelion • Animal food • cherries, tomatoes, apple • Trapped on animals • Cocklebur, clover Plant Domestication: Goes against natural selection for survival of the fittest.

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