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Plant Systems

Plant Systems. REVISE. TO DO Label the cross section of the leaf on your worksheet Chloroplast Stoma Lower epidermis Air Spaces Upper epidermis Spongy Mesophyll Cuticle Palisade Mesophyll Guard cells Oxygen Carbon Dioxide . AUTOTROPHS. What does this mean?

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Plant Systems

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  1. Plant Systems

  2. REVISE TO DO Label the cross section of the leaf on your worksheet Chloroplast Stoma Lower epidermis Air Spaces Upper epidermis Spongy Mesophyll Cuticle Palisade Mesophyll Guard cells Oxygen Carbon Dioxide

  3. AUTOTROPHS • What does this mean? • That they can produce there own energy • Two types of plants • Produce seeds eg. Flowering plants • Don’t produce seeds eg mosses and ferns • Land plants require??? • Water • Carbon dioxide • Oxygen • Sunlight

  4. Systems in plants Shoot system • organs above ground: leaves, stems and reproductive organs (flowers and seeds) Root system • organs below ground: roots and root hairs

  5. Plant tissues • Plants have specialised cells and tissues for particular roles such as: • storage, structure, transport, photosynthesis, respiration, growth and reproduction. • Important tissues include 1. Meristematic tissue 2. Dermal tissue including root hairs 3. Ground tissue includes all internal cells except vascular tissue 4. Vascular tissue

  6. 1. Meristematic tissue Cells division by mitosis for growth Found at the root, shoot tips and ring around the inside of stem and branches Cells differentiate into whatever type of cell/tissue is required. Allowing Growth in length and width

  7. 2. Dermal tissues • is the outer most layer of cells in plant tissues, eg. eipdermis layer • Protects the plant body from cuts, invasion by microorganisms and water loss. • Epidermal tissues include: • Waxy cuticle on leaves for protection • Fine hairs on roots for water absorption

  8. 3. Ground tissues • Internal plant cells (under the epidermal cells) other than the vascular tissue • Storage – starch • Support • Photosynthetic

  9. 4. Vascular tissues Transport of substances throughout plant Two main types: xylem and phloem

  10. Xylem cells transports water and nutrients from roots to the rest of the plant in one direction only (roots to leaves) mature cells are dead and have open ends to conduct water ‘tubular skeletons’

  11. Phloem cells • Transports sugars (sucrose) and other materials from leaves to other parts of the plant • Phloem cells are living • Two types of phloem cells: sieve cells and companion cells • Sieve cells • no nucleus • share cytoplasm • pass materials between sieve cells through sieve plates • Companion cells • have a nucleus and cell organelles to control each sieve cell

  12. Sucrose enters phloem through companion cell sieve cell diffusion. Water enters phloem from xylem through osmosis

  13. TO DO: What are the four different types of tissues found in plants? What do each do? Create a table to compare xylem and phloem.

  14. Transporting Systems Root system Anchoring Uptake of water and nutrients Fine root hairs increase surface area for more effective uptake

  15. Water Movement Root pressure water enters roots by osmosis, dissolved minerals (ions) enter roots by diffusion and active transport the pressure of osmosis, diffusion and active transport forces water and mineral ions into and up the xylem cells Shoot system Water moves up through xylem cells, sugars move down through phloem cells Xylem and phloem cells are found together in vascular bundles Vascular bundles are arranged differently in each section of the plant

  16. Transpiration • Continuous upwards movement of water is driven by the evaporation of water from the leaves • The constant loss of water by plants through leaves is called transpiration • The upward movement of water is aided by: • Adhesion; attraction between water molecules and the inside walls of xylem vessels • Cohesion; forces of attraction between individual water molecules

  17. Translocation The movement of glucose from where it is synthesised (photosynthesis in leaves) to other parts of the plant

  18. TO DO Explain the forces that enable water in a xylem vessel to reach the top of a tree?

  19. Gaseous Exchange Stomata control the movement of carbon dioxide in and water and oxygen out of leaves. Stomata are tiny pores found mostly in the lower epidermis of leaves Stoma open when guard cells absorb water and close when they lose water Stomata open in moist conditions and close in dry conditions, controlling the amount of evaporation

  20. TO DO Through what structure does gas exchange occur in plants? What is the function of the stomata? Draw a diagram to show how the stomata open and close Under what environmental conditions are stomata most likely to be open? How do stems and roots exchange gases with the environment?

  21. Removing wastes Deciduous plants: leaves before autumn Into bark that will peel or drop off Dead cells to form lignin (woody centre) Exude resins, fats, waxes or latex

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