Investigating transport in plants

• Ringing experiments

  • outer layers of the stem including phloem are removed
  • area above start to swell with liquids rich in sugars and other organic materials
  • some tissues below start to die
• Tracer experiments

  • plant supplied with carbon dioxide made from a radioactive carbon
  • these sugars can be tracked as they move through the plants using radiography
  • X ray film darkens when exposed to the radioactive carbon