Active phloem loading uses the apoplast pathway and uses energy and membrane-bound co-transporter protein and a proton pump to move sucrose into the sieve tubes.Passive phloem loading transports sucrose freely through plasmodesma in the symplast pathway.Apoplast Pathway1. The apoplast is the spaces outside of plant cell membranes within the cell walls where water and dissolved material can flow and diffuse freely.2. Glucose is manufactured in the chloroplasts by photosynthesis.3. This is converted to sucrose in the cytoplasm.4. The sucrose diffuses out of the photosynthesising cells into the spaces within the cell walls by facilitated diffusion down its concentration gradient.5. Hydrogen ions are actively transported from the companion cells into the spaces within the cell walls using ATP.6. The hydrogen ions then diffuse back into the companion cells through co-transporter proteins down a concentration gradient.7. Sucrose is co-transported into the companion cells with the hydrogen ions and then diffuses into the sieve elements through the plasmodesmata.8. Water enters the sieve tubes from the xylem (and companion cells) by osmosis.