Aphid experiments

• What do aphids feed on?

  Phloem sap
• How do aphids study phloem sap?

  By inserting their stylets into sieve tubes
• What does the flow of sap after aphid removal indicate?

  Sap is under positive pressure
• What hypothesis is supported by aphid experiments?

  The pressure-flow hypothesis
• What does the pressure-flow hypothesis explain?

  How sucrose moves from source to sink
• How can the rate of translocation be measured using aphids?

  By analyzing sap emergence from stylets
• What does the position of aphids along a stem indicate?

  How quickly sugars move in the phloem
• What does the bidirectional flow in phloem indicate?

  Sugars move from sources to sinks
• What is the role of radioactive tracers in aphid experiments?

  To track movement of labeled sugars
• What happens when plants are exposed to radioactive CO₂?

  It is incorporated into glucose via photosynthesis
• What do aphid experiments provide evidence for?

  Translocation in the phloem
• What are the key findings from aphid experiments regarding phloem transport?

  • The phloem is under pressure
  • Sugar moves at a measurable rate
  • Transport occurs in both directions
  • The process can be tracked using radioactive tracers