Transport in the phloem of plants
Understandings:
• Plants transport organic compounds from sources to sinks.
• Incompressibility of water allows transport along hydrostatic pressure gradients.
• Active transport is used to load organic compounds into phloem sieve tubes at the source.
• High concentrations of solutes in the phloem at the source lead to water uptake by osmosis.
• Raised hydrostatic pressure causes the contents of the phloem to flow towards sinks.
• Plants transport organic compounds from sources to sinks.
• Incompressibility of water allows transport along hydrostatic pressure gradients.
• Active transport is used to load organic compounds into phloem sieve tubes at the source.
• High concentrations of solutes in the phloem at the source lead to water uptake by osmosis.
• Raised hydrostatic pressure causes the contents of the phloem to flow towards sinks.
Skill: Analysis of data from experiments measuring phloem transport rates using aphid stylets and radioactively-labelled carbon dioxide.