What is a phloem?

• • Sieve cells/plates
  • Sieve tube element
  • Cytoplasm
  • Sugars (mainly sucrose)
  • Companion cells (with nucleus)
• Made of living cells
• Flow of substances in both directions
• Translocation - transport of sucrose
• Contains no lignin - not used for strength and support
• Seive element:

  Regulates movement of suagrs and other substances
• Companion cells:

  Carry out cellular reactions + Provides ATP (sometimes solutes need to go against the concentration gradient)

  • Can do this because they have a nucleus