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What is a plant?

What is a plant?. Multicellular Eukaryotic cell With cell wall of cellulose Waxy, protective coating called cuticle Usually contains chlorophyll for its role as an autotroph (photosynthesis). Plant Structures.

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What is a plant?

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  1. What is a plant? • Multicellular • Eukaryotic cell • With cell wall of cellulose • Waxy, protective coating called cuticle • Usually contains chlorophyll for its role as an autotroph (photosynthesis)

  2. Plant Structures External plant structures such as leaves, stems, roots, flowers, fruits, and seeds are known as plant organs. Each organ is an organized group of tissues that works together to perform a specific function. These structures can be divided into two groups: sexual reproductive and vegetative.Sexual reproductive parts produce seed; they include flower buds, flowers, fruit, and seeds. Vegetative parts include roots, stems, shoot buds, and leaves; they are not directly involved in sexual reproduction. Vegetative parts often are used in asexual forms of reproduction such as cuttings, budding, or grafting.

  3. Alternation of Generations Reproduction in Plants

  4. For growth Forms a Zygote e.g., Eggs/Sperm Archegonia/Antheridia For growth

  5. Sporophyte • “spore plant” • Diploid state • Many common plants have this as their dominant form

  6. Sporangium • Specialized organ • Diploid cells • Produces hapliod spores to release to the environment

  7. Meiosis in Sporangium • Reduction division • Starts with diploid number, finishes with haploid number in the new cells (spores)

  8. Spore • Haploid asexual reproductive cell • Released into the environment

  9. Mitosis • Growth of cell by replication of heredity and cell division into a multi-cellular organism

  10. Gametophyte • “gamete plant” • Produces gametes (sex cells) for sexual reproduction • Eggs from archegonia • Sperm from the antheridia

  11. Fertilization • Sperm nucleus unites with egg nucleus deep in the ovary of the plant

  12. Mitosis • Growth of cell by replication of heredity and cell division into a multi-cellular organism

  13. This multicellular organism is the next generation of sporophyte…..you are back to square one!

  14. For growth Forms a Zygote e.g., Eggs/Sperm Archegonia/Antheridia For growth

  15. Plant Phylogeny • Bryophyta – nonvascular, non-seed plants like mosses and liverworts • Psilophyta – non-seed vascular plants like tropical/subtropical whisk ferns • Lycophyta – non-seed vascular plants like club mosses • Sphenophyta – non-seed vascular plants like horsetails

  16. Plant Phylogeny (cont.) • Pterophyta – non-seed vascular plants like the ferns • Cycadophyta – vascular seed plants like the palm-like cycads • Gnetophyta – unusual, distinctive vascular seed plants like Welwitschia • Ginkgophyta – very rare vascular seed tree with fan-shaped leaves (1 species)

  17. Plant Phylogeny (cont.) • Coniferophyta – cone-bearing vascular seed plants like pine trees • Anthophyta – flowering vascular seed plants like roses (dicots) and lilies (monocots)

  18. Bryophyta • Non-vascular, so……. • Live in moist sheltered places • Non-seed • Mosses, hornworts, and liverworts • Plant life cycle needs water for sperm • Vegetative reproduction also

  19. 1 = sporophyte • 2 = gametophyte • 3 = sporangium case • 4 = stalk

  20. Ferns and their allies • Vascular plants (major advancement) • need water for reproduction • Seedless • Alternation of Generations • Ferns, club moss, horsetails • The beginnings of true organs

  21. Roots to anchor, absorb water and minerals, and store foodLeaves for photosynthesis and storage of foodStems for support, storage, and transport of water up and food down(Flowers for reproduction, yielding the fruit in seed plants)

  22. Gametophyte with young sporophyte Sporophyte

  23. Seed Plants • Vascular • Produce seeds (major advancement) • Gymnosperms (bear seeds naked on bracts of cones) and Angiosperms (flowering plants with seeds in tissues) • Free of water because male gametophyte is in pollen grain carried by wind, water, insects, or small animals

  24. Gymnosperms • Cone bearers • Gnetophytes, cycads, gingkoes, conifers • Alternation of Generations

  25. “Naked Seeds” Seeds lying uncovered on the bract

  26. Alternation of Generations

  27. Angiosperms (Phylum Anthophyta) • Flowering plants • Vascular seed plants • Fruits with seeds • Dry fruits • Fleshy fruits • Most of the commons plants we know • Alternation of Generations

  28. Alternation of Generations

  29. The Typical Flower (reproductive organ)

  30. A comparison of Classes Dicotyledonae vs Monocotyledonae

  31. XYLEM AND PHLOEM • XYLEM = “water UP” • PHLOEM = “food DOWN” VASCULAR BUNDLES HERBACEOUS STEM - GREEN WOODY TREE

  32. Plant Life Spans • Annual – germinate, grow, flower, seed, and die in one growing season • Biennial – germinate, grow, develop first season; flower, seed, and die second season • Perennial – live and flower (seed) for many seasons

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