A. TRANSLOCATION IN THE PHLOEM
Translocation:
The MOVEMENT of SUCROSE and AMINO ACIDS from the LEAVES (the SOURCE) to
GROWING REGIONS that are RESPIRING (the SINKS)
• The leaves are the source as sugars are made there, in photosynthesis.
• The growing regions are the sinks as sugars are transported there, and used in
respiration for growth
B. HOW SUCROSE IS TRANSPORTED IN THE PHLOEM
General principle
• Hydrostatic pressure is the pressure of a liquid – in this case, water.
• This is all about creating a hydrostatic (liquid) pressure gradient between the source
(leaves) and the sinks (growing regions = roots) from top to bottom.
• This is what makes the liquid containing dissolved sucrose move down.
SOURCE HIGH
HYDROSTATIC
(leaves) PRESSURE
SINKS LOW
HYDROSTATIC
(roots) PRESSURE
Translocation:
The MOVEMENT of SUCROSE and AMINO ACIDS from the LEAVES (the SOURCE) to
GROWING REGIONS that are RESPIRING (the SINKS)
• The leaves are the source as sugars are made there, in photosynthesis.
• The growing regions are the sinks as sugars are transported there, and used in
respiration for growth
B. HOW SUCROSE IS TRANSPORTED IN THE PHLOEM
General principle
• Hydrostatic pressure is the pressure of a liquid – in this case, water.
• This is all about creating a hydrostatic (liquid) pressure gradient between the source
(leaves) and the sinks (growing regions = roots) from top to bottom.
• This is what makes the liquid containing dissolved sucrose move down.
SOURCE HIGH
HYDROSTATIC
(leaves) PRESSURE
SINKS LOW
HYDROSTATIC
(roots) PRESSURE
