Transport Systems in Animals and Plants

Xylem

• Main carriageway for transporting water through the plant
• It is made of specialised xylem tissue
• Water enters the root system via osmosis

Phloem

• Phloem is the vessel that transports products of photosynthesis via active transport
• Phloem consists of two types of living cells:
  • Companion cells
    • Smaller cells found along the side of the sieve tube cells
    • Contain nucleus, mitochondria, vacuoles and other cell organelles
    • Control the activities of sieve tube cells
  • Sieve tube cells
    • Long and thin with large pores through the cell wall at either end
    • No nuclei, mitochondria or vacuole
    • Arranged end to end in sieve tubes