Transport in the phloem of plants

Topic 9.2

Essential idea: Structure and function are correlated in the phloem of plants.


9.2.U1 Plants transport organic compounds from sources to sinks

Diagram transport source to sink

9.2.U2 Incompressibility of water allows transport along hydrostatic pressure gradients

Incompressibility and hydrostatic pressure

9.2.U3 Active transport is used to load organic compounds into phloem sieve tubes at the source

Loading organic compounds using active transport

9.2.U4 High concentration of solutes in the phloem at the source lead to water uptake by osmosis

Movement of water from xylem to phloem

9.2.U5 Raised hydrostatic pressure causes the content of the phloem to flow towards the sink

Flow in phloem due to hydrostatic pressure


9.2.A1 Structure-function relationships of phloem sieve tubes

Explanation of structure-function relationship


9.2.S1 Identification of xylem and phloem in microscope images of stem and root

Place your mouse on the figure to view the cell types

xylem cells

Place your mouse on the figure to view the cell types

phloem cells

9.2.S2 Analysis of data from experiments measuring phloem transport rates using aphid stylets and                      radioactively-labelled carbon dioxide

Research paper phloem transport link Research paper on phloem transport
Aphids used in measuring phloem rate of flow
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