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Plant Biology

Plant Biology. 2 Systems 3 Tissues 2 Meristems Photosynthesis Growth Reproduction. Plant Body Systems. Two types of systems: Root System Shoot System: stem, leaf, flower Plant organs: root, stem, leaf, flower referred to as plant parts. Root System Function. Anchorage

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Plant Biology

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  1. Plant Biology 2 Systems 3 Tissues 2 Meristems Photosynthesis Growth Reproduction

  2. Plant Body Systems Two types of systems: • Root System • Shoot System: stem, leaf, flower Plant organs: • root, stem, leaf, flower • referred to as plant parts

  3. Root System Function • Anchorage • Keeps plant in the soil • Prevents soil erosion • Holds stem in place • Absorption • water • dissolved minerals • Storage • Starch • Other nutrients

  4. Types of Roots http://www.bio.miami.edu/dana/pix/taproot_fibrousroot.jpg http://kentsimmons.uwinnipeg.ca/2153/rootsystems1.jpg http://tchefty.wikispaces.com/file/view/rootsystems1.jpg/260637884/rootsystems1.jpg

  5. Taproot • Large long primary root • Penetrate deep into the ground • Small thin roots grow laterally off main root • Strong anchoring system • Examples: evergreen trees

  6. Taproot • Specialized to store water, food, nutrients • Better chance at drought survival • Examples: carrot, beet, turnip, radish http://www.ontarioweeds.com/media/jpg/tropr_root.jpg

  7. Fibrous Root • Many small roots that branch • Increases surface area • Better absorption of water and minerals • Less structural support • Examples: peas, beans, lettuce

  8. Root Hairs • Small fibrous objects that branch off roots • Absorbs water and minerals

  9. Root Zones • Zone of maturation: cells differentiate into different types of cells • Zone of elongation: allows the root to get deeper within the soil • Meristematic region: rapid mitosis of undifferentiated meristematic cells • Root cap: protects the meristematic region

  10. Shoot System • Stem • Leaf • Flower

  11. Stem • Raises and supports branches, leaves and flowers • Transport of water and nutrients • In trees the main stem is the tree trunk http://www.pxleyes.com/images/contests/bw%20tree%20trunks/fullsize/bw%20tree%20trunks_4b6283790291c.jpg

  12. Stem • Young green stems can perform photosynthesis because they have chloroplast in their epidermal cells

  13. Stem • Some are specialized for food storage • Examples: sugar cane, potatoes http://upload.wikimedia.org/wikipedia/commons/9/96/Sugar_Cane.jpg

  14. Leaf • Main function: Photosynthesis • Parts of the Leaf: • Cuticle • Epidermis • Guard Cells & Stoma • Palisade cells • Spongy Layer • Vascular Tissue

  15. Epidermis • Outer layer of cells • Leaf epidermis produces cuticle http://www.goldiesroom.org/Multimedia/Bio_Images/05%20Nutrition/15a%20Cross%20Section%20of%20a%20Leaf.jpg

  16. Cuticle • Waxy substance that coats the exterior • Water proofing • Protect interior tissues • Blocks passage of gases http://www.goldiesroom.org/Multimedia/Bio_Images/05%20Nutrition/15a%20Cross%20Section%20of%20a%20Leaf.jpg

  17. Guard Cells & Stoma • Stoma (Greek for “mouth”) • Pore-like openings in the plant’s epidermis • Opening size controlled by two guard cells • permits gas exchange between the leaf’s interior and external environment. • larger opening, faster gas exchange

  18. Guard Cells & Stoma

  19. Spongy Layer • Where water is stored • Where the vascular tissues reside

  20. Palisade Cells • Contains many chloroplast for photosynthesis • Cells stand tall and upright • Top end exposed to light • Bottom end exposed to the gases in the spongy layer

  21. Chloroplast Structure • Thylakoids are flat disc-like structures where chlorophyll is embedded • Grana are thylakoids arranged in a stack • Chlorophyll is a pigment that captures light energy

  22. Chloroplast Function • Site for starch (a type of sugar) storage • Site for photosynthesis • Reaction involves trapping light energy to create food in the form of sugars • Starting substances are carbon dioxide and water CO2 + H2O + energy  O2 + glucose

  23. Leaf Cross Section • Scanning electron microscope image of a leaf from a Black Walnut tree. (Dartmouth Electron Microscope Facility/Dartmouth College) http://cache.boston.com/universal/site_graphics/blogs/bigpicture/micro_11_14/m04_walnut_leaf.jpg

  24. Modified Leaf: Cactus

  25. Poinsettia Leaves

  26. Flower • Specialized structures developed for sexual reproduction known as pollination • Can contain both male and female reproductive structures in the same flower

  27. Flower Parts • Male reproductive organ: stamen • Female reproductive organ: pistil http://www.exploringnature.org/graphics/teaching_aids/flower_parts_color72.jpg

  28. Flower Parts • Male gametes: pollen grains found on anther • Female gametes: ovule housed in ovary

  29. Pollination • Act of sexual reproduction in plants • Pollen reach stigma, travel down the style into the ovary to fertilize the ovule

  30. Methods of Pollination: Wind • Pollen grains blown by wind • Plants are often small and drab but produce a large amount of pollen • Example: grass http://www.vcbio.science.ru.nl/images/pollen/pollen-grass-stigma.jpg

  31. Methods of Pollination: Animals • Pollinators: • Animals: birds, bats, and on fur of land animals • Insects: bees • Plants attract pollinators with: • Large, colourful fragrant flowers • nectar http://4.bp.blogspot.com/_Xla0E3fwLto/S4CL_NstZuI/AAAAAAAABP4/PgoWyz-Mk2w/s400/4342259001_e10572466d_b.jpg

  32. Methods of Pollination: Animals • Example: Dandelion plant attracting bees http://guelph.ca/uploads/Healthy%20Landscapes/Pollination_Bee_Dandelion_Zoom.jpg

  33. After Pollination • Zygote (fertilized egg) becomes the seed • Ovary becomes the fruit

  34. After Pollination • Zygote (fertilized egg) becomes the seed • Ovary becomes the fruit http://www.biosci.ohio-state.edu/~plantbio/osu_pcmb/pcmb_lab_resources/images/pcmb101/flwrs_sds_frts/where_fruit.jpg

  35. After Pollination http://greatneck.k12.ny.us/gnps/shs/dept/science/krauz/bio_h/images/38_09FruitDevelopment_L.jpg

  36. Plant Tissue • Dermal Tissue • Vascular Tissue • Ground Tissue

  37. Dermal Tissue • Outermost layer of a plant • Epidermis: thin layer of cells that covers the surface of leaf, stem and root • Periderm tissue: bark on stem and large roots of woody plants (replaces the epidermis)

  38. Dermal Tissue • Some dermal tissues have unique functions • Root cells: root hairs (long extensions) • Leaf cells: produce cuticle

  39. Vascular Tissue • Plant circulatory system • Vessels that connect roots to leaves • Transports water, dissolved minerals, and sugars throughout plant, providing cells with materials to carry out life functions • Two types: • Xylem • Phloem

  40. Vascular Tissue: Xylem • made up of long hollow tubes formed by non-living cell walls (left over from plant cells that have died) • transports water and dissolved minerals upwards from roots

  41. Vascular Tissue: Phloem • Made up of elongated cells that are living • Transports: • solutions of sugars (food) • Dissolved nutrients • Hormones • Bi-directional movement of materials • downward to roots • upward to leaves

  42. Vascular Bundle

  43. Plant Sugars • Starch is NOT soluble in water • Starch can be broken down into sucrose • Sucrose IS soluble in water • Sucrose is transported through the phloem to the plant parts that require it • Sucrose can be broken down into glucose • Glucose is used in cellular respiration to make cellular energy Starch  sucrose  glucose

  44. Spring • Trees need energy to grow leaves • Energy comes from cellular respiration of glucose: Glucose + oxygen  carbon dioxide + water + energy • Glucose can be obtained by: • Photosynthesis - but spring trees don’t have any leaves to do photosynthesis • Converting it from starch

  45. Spring • Starch • Stored in the roots • Insoluble in water so it cannot be transported through phloem • Convert to sucrose • Sucrose • Soluble in water • Transport from root to tree bud through phloem • Convert to glucose in tree bud • Glucose • Use in cellular respiration • Converted to cellular energy needed to grow leaves

  46. Tree Sap

  47. Plant Sugars

  48. Summer • Once leaves have grown, they can perform photosynthesis to produce their own glucose • Glucose is converted to sucrose and transported through the phloem to the roots • Sucrose is converted to starch in the roots for storage

  49. Sugar Movement through Phloem Glucose (leaves) Sucrose (stem) Starch (roots) Winter storage Spring Summer and Fall Summer and Fall Spring http://www.nuscentscandle.com/blog/wp-content/uploads/tree-sap.jpg

  50. Cells in the Root • Cells in the root have no chloroplasts and are not exposed to sunlight so they can not undergo photosynthesis to make their own food • Root cells must perform cellular respiration to obtain cellular energy Glucose + oxygen  carbon dioxide + water + energy • Glucose comes from the starch stored in the root • Oxygen is absorbed through the soil

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