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06 vascular tissue


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06 vascular tissue

  1. 1. Vascular tissue
  2. 2. PLANTS Vascular plants need to transport substances between the roots, stems, and leaves. Xylem – transports water and nutrients from soil (i.e. minerals) Phloem – transports sugar Vascular tissue
  3. 3. PLANTS Vascular tissue Review: Some key terms Diffusion Osmosis Passive Transport Active Transport
  4. 4. PLANTS Vascular tissue Diffusion: Substances move from areas of high concentration to areas of low concentration.
  5. 5. PLANTS Vascular tissue Osmosis: Diffusion of water Water can diffuse into and out of cells based on concentration of solute inside and outside a cell.
  6. 6. PLANTS Vascular tissue Passive transport: Movement of substance across a membrane without using energy Passive transport relies on diffusion and concentration gradients.
  7. 7. PLANTS Vascular tissue Active transport: Movement of substances across a membrane using energy against concentration gradient.
  8. 8. PLANTS Xylem -Transports water. -xylem is made up of long hollow tubes formed by non-living cell walls, called tracheids or vessel elements. -This non-living matter was once living. (cells die, leaving cell walls as tubes) Vascular tissue
  9. 9. PLANTS Xylem Tracheids Vascular tissue
  10. 10. PLANTS Xylem Vessel elements Vascular tissue
  11. 11. PLANTS Xylem Tracheids vs. vessel elements Vascular tissue
  12. 12. PLANTS Into the roots… In the roots, water crosses* through the cortex. Then it must pass through the endodermis. The Casparian strip of the endodermis blocks substances from passing between endodermis cells. Vascular tissue
  13. 13. Vascular tissue PLANTS Into the roots… *Water either enters the cortex cells by 1) osmosis from cell to cell 2) flows between cells. Minerals are actively pumped across cell membranes into the xylem. H2O
  14. 14. PLANTS Into the roots… Root pressure – nutrients pumped into the xylem cause water to follow by osmosis Vascular tissue
  15. 15. PLANTS Into the stem… Water has to move against gravity in the stems. Accomplished by root pressure and capillary action. Vascular tissue
  16. 16. PLANTS Into the stem… Capillary action – water molecules stick to each other and can rise up narrow tubes (like the xylem) Capillary action increases as the diameter of the tube decreases. Vascular tissue
  17. 17. PLANTS Into the stem… Cohesion-adhesion– Cohesion – force that holds water molecules together Adhesion – water molecules stick to certain surfaces Vascular tissue
  18. 18. PLANTS Into the leaves… Water moves to the leaves due to transpiration. Transpiration – Evaporation of water through stomata of leaves Vascular tissue
  19. 19. PLANTS Vascular tissue Plants need water to maintain turgor pressure. Turgor pressure – pressure caused by fluid pushing against the cell wall Without turgor pressure, plants will wilt
  20. 20. PLANTS Phloem -Transports dissolved nutrients (food) -Phloem tissue is made up of living tissue -Made of -companion cells -sieve tube element -sieve plate Vascular tissue
  21. 21. PLANTS Vascular tissue Phloem Companion cell Assists the survival of sieve tube cells Sieve tube (cells without a nucleus forming a hollow tube) Sieve plate (perforated end of sieve tube cells)
  22. 22. PLANTS How does sugar move through the phloem? Both active and passive transport from source cells to sink cells. Source cells: Cells with high concentration of sugar (i.e. leaf cell) Sink cells: Cells with low concentration of sugar (i.e. root cell) Vascular tissue
  23. 23. PLANTS Phloem & tree sap -In plants, roots store STARCH, a polysaccharide which is NOT soluble in water. -Starch is broken down into SUCROSE, a disaccharide which IS soluble in water. -In the spring, the SUCROSE is then transported from the roots (where it is stored during the winter) to the developing leaves through phloem. -The leaves convert the SUCROSE into glucose, a monosaccharide. Vascular tissue
  24. 24. PLANTS Phloem & tree sap -The glucose provides energy for the GROWTH OF LEAVES. -Once leaves have grown, they can perform PHOTOSYNTHESIS to produce their own glucose. -Excess glucose is converted into STARCH in the chloroplasts (an organelle). -The STARCH is then converted into sucrose, which is transported to the ROOTS through the phloem. Vascular tissue
  25. 25. PLANTS Phloem & tree sap -The carbohydrate that plants transport in the phloem is SUCROSE, a disaccharide. -Sucrose is converted into the polysaccharide STARCH in the roots -Sucrose is converted into the monosaccharide GLUCOSE in the leaves in early spring. Vascular tissue
  26. 26. PLANTS Phloem & tree sap Glucose (leaves) Spring Summer and Fall Sucrose (stem) Spring Summer and Fall Starch (roots) -winter storage Vascular tissue