Root hair cells and water transport

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Root hair cells and water transport

  1. 1. Transport in plants<br />
  2. 2. Evidence for movement of water through xylem<br />If the cut end of shoot is placed in a solution of eosin dye, the dye is carried into the transport system and through to the vascular tissue of the leaves.<br />
  3. 3. Lignified Xylem Vessels<br />Lignified xylem vessels are very strong and play a very important supportive role in the stems of plants, particularly larger plants.<br />
  4. 4. Why young plants wilt if water is lost from them?<br />In smaller, non-woody plants support comes mainly from the turgid cells in the centre.<br />This is why young plants wilt if too much water is lost.<br />
  5. 5. Cambium<br />Cambium is a layer of unspecialised cells which divide, giving rise to more specialised cells that form both the xylem and the phloem.<br />
  6. 6. Where on the leaf do you find stomata?<br />
  7. 7. Transpiration occurs on which side of the leaf?<br />
  8. 8. Root Hair Cells<br />
  9. 9. Root Hair Cells<br />
  10. 10. Root Hair Cells<br />
  11. 11. Root Hair Cells<br />The thin hair-like extension of each cell gives a large surface for water to enter into the root.<br />
  12. 12. Absorption of Water<br />
  13. 13.
  14. 14. Translocation<br />The movement of substances around plant is called translocation<br />
  15. 15. Transpiration<br />The movement of water in the xylem of plants depends on transpiration.<br />Once in the leaves, water moves by osmosis from the xylem in the veins of the leaves into the mesophyll cells.<br />Water then evaporates from the cellulose walls of the spongy mesophyll cells into the air spaces.<br />The water vapor moves through open stomata into the external air along a diffusion gradient.<br />
  16. 16. Measuring water loss from a plant<br />
  17. 17. Cohesion and Adhesion<br />Water molecules stick together one after due to cohesion.<br />Water molecules also adhere strongly to the walls of narrow xylem vessel. This attraction between unlike molecules is called adhesion.<br />
  18. 18.
  19. 19. Cohesion and Adhesion<br />The combination of adhesive and cohesive forces pulls the whole column of water in the xylem upwards.<br />More water is continuously moved into the roots by osmosis from the soil to replace that lost from the leaves by transpiration.<br />
  20. 20. Factors that affect transpiration<br />Temperature<br />Humidity<br />Light intensity<br />Wind<br />

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