Onion cell walls

Class: 6, 5.

Lesson: Cellules

Rationale: Show the membrane and cell wall of a plant cell by separating the two by osmosis.

Materials:

See "Onion cells" above.
salt solution (1 tsp of salt in 100 ml of water)

Procedure:

1. Do preparation as in "Onion cells" but before adding the iodine add two drops of salt solution and wait two minutes.

2. The membrane will separate from the cell wall except for at the ends of the cell where it remains attached.

Source: Johnson Hunting with the Microscope.