Translocation

• Distribution of sugars and other organic compounds manufactured in leaves (sources: where they are made/stored) to the rest of the plant (sinks: where they are transported)
• Main sources are leaves, organic molecules are synthesised in photosynthesis, also storage organs (e.g. roots) and the main sinks are roots (stores starch), flowers (nectar), fruits or any growing region of the plant
• Leaves produce large amounts of glucose; converted to sucrose (because it is not used in metabolism) for transport, when it reaches the cells, it’s converted back for respiration, to starch for storage or used to produce other compounds
• Products transported are called assimilates and go sources to sinks; phloem loading substances move around the plant at ~0.15-7 metres per hour in mass flow (bulk transport from high hydrostatic pressure to a low hydrostatic pressure)
• Phloem diagram (Label H should be touching the inside of the white structure)

  A) Cellulose cell wall

  B) companion

  C) nuclear envelope

  D) nucleolus

  E) nuclear pore

  F) Ribosomes

  G) mitochondrion

  H) cytoplasm

  I) Tonoplast

  J) Vacuole

  K) Rough Endoplasmic Reticulum

  L) plasmodesmata

  M) Cellulose cell wall

  N) sieve tube

  O) phloem protein strand

  P) mitochondrion

  Q) endoplasmic reticulum

  R) thin

  S) cytoplasm

  T) lumen

  U) sieve pore

  V) sieve plate

  W) phloem protein

  X) pore