translocation

• 1. solutes are actively transported (co-transport) from source cells -> companion cells -> sieve tubes
• 2. This lowers the water potential so water also moves by osmosis into the sieve tubes
• 3. This creates a high pressure in the sieve tubes near the source cells
• 4. Since solutes are used up or stored in sink cells the opposite happens in sink cells
• 5. This creates a pressure gradient between the two sites
• 6. Water and solutes move down the pressure gradient