Translocation (OCR A-Level Biology A): Flashcards
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Translocation definition
Translocation definition
Movement of dissolved photosynthetic assimilates through plant
Main substance transported in translocation
Main substance transported in translocation
Sucrose
Why sucrose ideal for transport (3 properties)
Why sucrose ideal for transport (3 properties)
Soluble, chemically unreactive, less effect on water potential
Source in translocation
Source in translocation
Region with high sucrose concentration
Sink in translocation
Sink in translocation
Area requiring sugar, with low sucrose concentration
Ringing experiment result
Ringing experiment result
Sucrose accumulates above ring, can't pass - proves phloem needed
Mass flow hypothesis
Mass flow hypothesis
Pressure-driven bulk flow of solution through sieve tube elements
Role of companion cells in translocation
Role of companion cells in translocation
Provide ATP for active transport of sucrose into sieve tubes
How pressure created at source
How pressure created at source
Sucrose loaded, lowers water potential, water enters by osmosis
Pressure gradient in phloem
Pressure gradient in phloem
High pressure at source, lower pressure at sink drives mass flow