Technical details for germination investigations:
These are a modified version of an original experiment in the SAPS in
house publication Osmosis 3 (September 1995) which can be seen at
http://www-saps.plantsci.cam.ac.uk/worksheets/ssheets/ssheet5.htm
This used a plastic lemonade bottle cut to form a germinating chamber.
The seeds were placed on filter paper in a Petri dish and these inserted
into the bottle as shown. Conditions affecting germination could then be
investigated
This, or the new chamber made from a plastic food takeaway container,
can be used to investigate the effect of a heavy metal, such as copper, on
germination and growth.
The seeds used are white mustard, Sinapsis alba, as they are cheap, large
enough to enable pupils to handle them and have a short and consistent
germination time.
The solution containing copper is made using either anhydrous copper(11)
sulphate (molecular mass 159.68) or copper(11) sulphate 5-water
(molecular mass 249.68). A stock solution of 1000ppm w/v is prepared
using either by dissolving 2.51g (anhydrous form) or 3.92g (5-water form)
in 1dm3 of distilled water. This can then be serially diluted to give
solutions from 10-200ppm.
100cm3 of each solution was placed in each germinating chamber. The
seeds were placed on the dampened filter paper over the grids on the
appropriate spaces. The dishes were kept in a flat position for at least 30
minutes to allow seeds to absorb solution and “stick” to the paper.
Prepared Petri dishes with 5 or 10 seeds stuck on were then placed in
each germinating chamber. (see section of ASE Talk ‘07 powerpoint)
Once prepared the germinating chambers were placed under a light bank
for 5 days before measuring and recording results.
As the grid used is of 2mm squares it is possible just to count the number
of squares to calculate the length of root and shoot.