02 plant structures

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02 plant structures

  1. 1. Plant structures
  2. 2. PLANTS Angiosperms -Divided into two groups: monocots and dicots The names come from parts of the embryo in the seed Radicle = embryonic root Hypocotyl = embryonic stem Cotyledon = seed leaf (may have one or two) Classifying plants
  3. 3. PLANTS Angiosperms: Monocots Monocots – contain one cotyledon (ex. corn) →Two types: “Woody” stems (tough and rigid) About 10% of all monocots i.e. Bamboo, palm trees Herbaceous stems (soft and fleshy) i.e. Orchids, tulips, grasses, wheat Classifying plants
  4. 4. PLANTS Angiosperms: Dicots Dicots – contain two cotyledons (ex. Beans) Ex. Most of Canada’s native trees, many wildflowers, tomatoes, lettuce, yams, beans, etc. Classifying plants
  5. 5. PLANTS Monocots vs. dicots
  6. 6. PLANTS Monocots vs. dicots
  7. 7. PLANTS Monocots vs. dicots Monocot leaves Dicot leaves Parallel-veined leaves Net-veined leaves
  8. 8. PLANTS Monocots vs. dicots Monocot stem Dicot stem Primary vascular bundles scattered Primary vascular bundles in a ring
  9. 9. PLANTS Monocots vs. dicots Monocot flower Dicot flower Petals: multiples of 3 multiples of 4 or 5
  10. 10. PLANTS Monocots vs. dicots
  11. 11. PLANTS Angiosperms: Reproduction -Flowers are used for reproduction -Usually colourful and attractive to attract animals -Animals visiting flowers to collect nectar or pollen assist with pollination -pollination = transferring of pollen from male to female plant - Flowers adapt to pollinators (i.e. shape, scent) Classifying plants
  12. 12. PLANTS Angiosperms: Reproduction Stamen – “male” reproductive organ (produce pollen) Carpel – “female” reproductive organ (produce ovum) Classifying plants
  13. 13. PLANTS Angiosperms: Reproduction Seeds and Fruits -Flowering plants are sporophytes (2n) -The pollen and ovum that they produce are gametophytes (1n) -The seed is the result of fertilization. -After fertilization, the ovary walls in the flower swell, become fleshy, and form either the fruit or seed pod Classifying plants
  14. 14. PLANTS Gymnosperm vs. angiosperm Classifying plants
  15. 15. PLANTS The Leaf: The main role of the leaf is to convert solar energy into chemical energy through photosynthesis. Parts of the Leaf: Epidermis Stoma Spongy Layer Vascular Tissue Palisade cells Structures
  16. 16. PLANTS The Leaf: Epidermis Cuticle -waxy non-living exterior that allows for water proofing -to protect their interior tissues -composed of cells tightly packed together. The cuticle is so effective, it can also block the passage of gases through the cells of the epidermis. Structures
  17. 17. PLANTS The Leaf: Epidermis Cuticle So how does CO2 and water molecules needed for photosynthesis enter the leaf? Through the stoma Structures
  18. 18. PLANTS The Leaf: Epidermis Stoma (Greek for “mouth”) -pore-like openings in the plant’s epidermis -function – to permit gas exchange between the leaf’s interior and external environment. -The larger the opening, the faster the gas exchange -The size of the opening is controlled by two guard cells. Structures
  19. 19. PLANTS The Leaf: Epidermis Stoma and Guard Cells Structures
  20. 20. PLANTS The Leaf: Spongy Layer -Where water is stored. -Water vapour will be released through the stomata in a process called transpiration. Structures
  21. 21. PLANTS The Leaf: Vascular Tissue The VEINS – made up of xylem and phloem which are bundled together in thin strands. They allow the movement of water and nutrients Think back to the veins in a dicot and monocot flower. Which veins are parallel and which are net-like? Structures
  22. 22. PLANTS The Leaf: Palisade Cells -Palisade cells act like a solar panel. -In dicot leaves, the palisade cells stand tall and upright. -The top end of the palisade cell’s surface is exposed to light. -The bottom end is exposed to the gases in the spongy layer. -This allows photosynthesis to take place by chloroplasts Structures
  23. 23. PLANTS The Leaf: Outer characteristics -the stalk that attaches the leaf to blade to the plant stem is the petiole Structures
  24. 24. PLANTS The Stem: Epidermis -Outermost layer of the stem -Contains chloroplasts, cuticle, stomata -Allows for photosynthesis to take place -Also protects the inner tissues of the stem Structures
  25. 25. PLANTS The Stem: Vascular Tissue -Contain both xylem and phloem -In dicots, the tissue is arranged in a ring -In monocot, the tissue is scattered everywhere. Structures
  26. 26. PLANTS The Stem: Pith -Found in the center of the stem -Contains air spaces (spongy tissue) -Stores water and some nutrients. Structures
  27. 27. PLANTS The Stem: Cortex -Layer of tissue surrounding the pith. -Rigid tissue -Structural support -Also stores water and some nutrients Structures
  28. 28. PLANTS The Roots: -Anchors the plant in the soil and holds the stem in place -Prevents erosion -Roots absorb water required for photosynthesis and replace water loss during transpiration. -Absorb dissolved minerals -Store starch that is made by the leaves Structures
  29. 29. PLANTS The Roots: 2 types Fibrous Roots – large number of slender roots Taproot – one large root. Ex: Beets, carrots, turnips and radishes. Which type of root is more effective in preventing erosion? Structures
  30. 30. PLANTS The Roots: 4 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. Structures
  31. 31. PLANTS The Roots: Epidermis -Contain root hairs on the surface. -Protects the interior root structures. -Absorbs water and dissolved minerals from the soil. Structures
  32. 32. PLANTS The Roots: Epidermis -Roots epidermal cells have no chloroplasts therefore they cannot make food. -The root cells must perform cellular respiration (what humans use) in order to stay alive. -The GLUCOSE comes from the starch in the cortex of the root. Structures C6H12O6 + 6O2  6CO2 + 6H2O + energy
  33. 33. PLANTS The Roots: Cortex Lies inside the root’s epidermis Contain vacuoles for food storage The purple colour observed in photographs is the starch that is stored in the vacuoles. (purple is the dye that was used) Structures
  34. 34. PLANTS The Roots: Endodermis -Inside the cortex -Carefully filter materials travelling into the center of the root. - Filtering stops harmful substances from entering the plant. -It has a selectively permeable membrane. It only allows certain molecules to pass through. -Therefore the root endodermis, determines what enters the entire vascular system for transport to the rest of the plant. Structures

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