1 / 23

Experiments that show the movement of substances in xylem and phloem

Experiments that show the movement of substances in xylem and phloem. How can we show that water is being transported in the xylem?. Using these materials…. Red ink A plant (eg celery) Microscope Knife. Examine the section under microscope. Transverse sectioning of stem.

sigourney-wiley
Download Presentation

Experiments that show the movement of substances in xylem and phloem

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Experiments that show the movement of substances in xylem and phloem

  2. How can we show that water is being transported in the xylem?

  3. Using these materials… • Red ink • A plant (eg celery) • Microscope • Knife

  4. Examine the section under microscope Transverse sectioning of stem

  5. Under the microscope……

  6. Evidence • Xylem stained red. • Water is being transported in the xylem.

  7. How can we show that food is being transported in the phloem?

  8. Translocation • Transportation of manufactured food products (sugars and amino acids) in the phloem is known as translocation.

  9. Leaves • Source • Location where food is manufactured • Fruits/roots • Sink • Location where food is being transported to.

  10. Movement of sugars in the phloem • Using aphids • Using carbon-14 isotopes. • Using the ’ringing experiment’

  11. Using aphids Feed on the stems

  12. How can we use aphids to show that sugar transport occurs in the phloem?

  13. Carbon dioxide Sieve tubes

  14. Evidences • Liquid the exude out of the cut end of the proboscis contain sugar and amino acid. • Viewed under microscope, proboscis found embedded in the sieve tube.

  15. Think about it! • Why do plantations infested with aphids have reduced fruit yield?

  16. Using the ringing experiment • Remove the bark of the tree would remove the phloem and the cambium. • Predict what would happen at the cut region?

  17. Using the ringing experiment • The region above the cut end swells due to the accumulation of sugar.

  18. Evidences from ‘ringing’ expt • Removing of bark remove phloem. • Swelling above the cut region shows that sugar is being accumulated in that region as phloem transport is being disrupted.

  19. Use of radioactive Carbon-14 isotopes 12CO2 14CO2 Radioactive

  20. Use of radioactive Carbon-14 isotopes 14CO2 + H20  14C6H1206 + C02 + H20 Sugar transported in the phloem also show radioactivity.

  21. Put an x ray film on top Cross section of stem

  22. Evidences • Plants exposed to radioactive 14CO2 would contain radioactive sugar in the phloem. • The presence of radioactive sugars is detected by an x-ray film.

  23. Think about it! Young leaf exposed to carbon dioxide. No radioactivity detected . Why?

More Related