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

• Identify phloem within the vascular bundle of a stem and root. 

9.2.A1:  Structure-function relationships of phloem sieve tubes

• State that the function of phloem includes loading of carbohydrates at a source, transport of carbohydrates through the plant, and unloading of carbohydrates at a sink.

• Outline the structure and function of sieve tube cells, with specific mention of the rigid cell wall and sieve plates. 

• Outline the structure and function of companion cells, with specific mention of mitochondria and cell membrane infolding

Review of vascular plants

Xylem vs phloem 

Xylem vs Phloem CFU

Phloem structure presentation notes

Phloem histology handwritten notes

Phloem structure handwritten notes  

Phloem structure CFU

Virtual phloem histology lab

9.2.U1:  Plants transport organic compounds from sources to sinks

• Define translocation, phloem sap, source and sink.

• List example source and sink tissues.

• State that phloem transport is bidirectional.

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

• State that sucrose is the most prevalent solute in phloem sap.

• Outline why sucrose is used for phloem transport, as opposed to glucose.

• Describe the active transport of sucrose into the phloem via a co-transport protein.

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

• State that the phloem becomes hypertonic to xylem due to the active transport of sucrose into the phloem.

• State that water moves into the phloem by osmosis.

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

• Outline why pressure in the phloem increases due to the movement of water into the phloem.

9.2.U5:  Raised by hydrostatic pressure causes the contents of the phloem to flow toward sinks

• State that water moves from area of higher pressure to area of lower pressure and that the movement of water also moves the solutes dissolved in it.

Intro to translocation notes

Phloem function presentation notes

Modeling phloem loading video

Diagram for pressure flow model

Phloem function video

Create a model of pressure flow

Phloem loading model

Source vs sink CFU

Pressure flow model CFU

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

• State that aphids consume phloem sap as the main component of their diet.

• Outline how aphids have been used to measure the rate of flow and composition of phloem sap.

9.2.NOS:  Developments in scientific research follow improvements in apparatus-experimental methods for measuring phloem transport rates using aphid stylets and radioactively-labeled carbon dioxide were only possible when radioisotopes became available

• Outline how radioactive carbon isotopes are used to study translocation.

Aphids and Phloem

Aphids and Phloem CFU

Aphids and Phloem original paper

George Zaidan: The bug that poops candy | TED Talk

Final knowledge audit

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Kahoot review

Quizizz review